Another FT 3126 is having the same issues with oil loss I had, and it seems to be #6. Number 6 in my terms is, the cylinder above the bell housing. It is actually # 6 in firing order
The other 3126 that Chris mentions as having an issue would be mine, and Chris has been a huge help in diagnosing mine, but it seems a little different than the OP's mixing of oil & coolant. Mine is losing roughly a quart of oil every 1k miles and blowing smoke out of the vent tube, covering the bumper of my tow car. I can't be sure yet if it's being burned, blown out the vent tube, or leaked out of a gasket. No smoke from the tail pipe. Starts and runs fine. No coolant in the oil, or oil in the coolant...that I can tell. And, yes, I am sure that the oil is not overfilled. I've added a gallon over the last 4k miles and it keeps dropping well below the fill line. This is a very recent development that has not happened in the prior 13 years that I've owned the coach. I've checked for oil in the fuel at both the tank and the filter....none. I've checked for oil getting past the turbo....none. My only real clue at this point that leads to suspecting blowby at cylinder #6 is that it is measurably cooler than the others. Infra-red photos show the exhaust manifold to be about 40deg cooler than the others.
I'm waiting on an oil analysis to be returned by Blackstone, which may or may not help. After that, it's probably going to Cat for diagnosis. So, I'll be curious to see how BillO's works out. I don't want this to Hijack his thread so I'll probably start a new one when I know more about mine.
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: Pierce & Gaylie Stewart on November 30, 2018, 10:43:48 am
Could be a stuck top ring. That would account for the blowby but since the oil ring is OK, not using any oil. You need to figure out if it's got a leak or if it's all coming out of the crankcase vent. They do make gauges so you can block the crankcase vent and then check the oil fill for the amount of pressure. But, if you have a cool cylinder, that may indicate a stuck compression ring, usually the top one.
Do you let your engine idle for long periods? Carbon buildup in the ring lands can cause a ring to stick. If a ring sticks, sometimes it may be cured by pulling the injector and chemically treating the deposits. You then should either turn the engine over with the injector out or by a breaker bar so you don't get a hydraulic lock and possibly bend a rod with the starter motor. I witnessed that happening once.
I can't think of another reason for one cylinder to be cool with blow by at the same time. A cracked cylinder wall would introduce products of combustion into the cooling system where it could be detected but you have not had any overheating problems, correct?
When did you measure the manifold temperature, under load or idle.? Tight valve could drop the temp at idle.
Here is a site for testing Cummins B engines. The hole you drill would have to be larger for your increased displacement.Measuring Blow by, The Real Test For Internal Engine Condition - Seaboard Marine (https://www.sbmar.com/articles/measuring-blow-by-the-real-test-for-internal-engine-condition/)
Easiest thing to try first would be a fuel and crankcase additive. See below quote:
Problem: This is a CAT excessive blow-by issue caused by: diagnoseCause: Fuel, air, and moisture forced past the rings into the crankcase, or contaminated and diluted oil in the crankcase infoSSolution: Use Stiction Eliminator and Diesel Extreme Fuel Additive to free up both sides of piston rings. If the piston rings are worn out, they will need to be replaced.
Pierce
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: John and Stacey on November 30, 2018, 10:56:00 am
On my 3126, had a bad injector. The bad injector cylinder did show to be cooler, because it was not firing. I was also using oil at the time. Changed out injector and oil consumption ended. Went to Colorado twice this year and only added 2 quarts of oil. 150,xxx miles and so far so good. If this engine fails I want to be in Chris's neighborhood. The dipstick has been checked to be accurate. Still love my CAT.
John
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: craneman on November 30, 2018, 11:01:03 am
The other 3126 that Chris mentions as having an issue would be mine, and Chris has been a huge help in diagnosing mine, but it seems a little different than the OP's mixing of oil & coolant. Mine is losing roughly a quart of oil every 1k miles and blowing smoke out of the vent tube, covering the bumper of my tow car. I can't be sure yet if it's being burned, blown out the vent tube, or leaked out of a gasket. No smoke from the tail pipe. Starts and runs fine. No coolant in the oil, or oil in the coolant...that I can tell. And, yes, I am sure that the oil is not overfilled. I've added a gallon over the last 4k miles and it keeps dropping well below the fill line. This is a very recent development that has not happened in the prior 13 years that I've owned the coach. I've checked for oil in the fuel at both the tank and the filter....none. I've checked for oil getting past the turbo....none. My only real clue at this point that leads to suspecting blowby at cylinder #6 is that it is measurably cooler than the others. Infra-red photos show the exhaust manifold to be about 40deg cooler than the others.
I'm waiting on an oil analysis to be returned by Blackstone, which may or may not help. After that, it's probably going to Cat for diagnosis. So, I'll be curious to see how BillO's works out. I don't want this to Hijack his thread so I'll probably start a new one when I know more about mine.
When you start a new thread on this maybe have the #6 and one of the other cyls. compression checked. If there is a big difference, you will know the problem. The low temp and blowby usually are the result of lack of compression either by scored cyl. or bad piston.
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: gracerace on November 30, 2018, 11:03:26 am
Could be a stuck top ring. That would account for the blowby but since the oil ring is OK, not using any oil. You need to figure out if it's got a leak or if it's all coming out of the crankcase vent. They do make gauges so you can block the crankcase vent and then check the oil fill for the amount of pressure. But, if you have a cool cylinder, that may indicate a stuck compression ring, usually the top one.
Do you let your engine idle for long periods? Carbon buildup in the ring lands can cause a ring to stick. If a ring sticks, sometimes it may be cured by pulling the injector and chemically treating the deposits. You then should either turn the engine over with the injector out or by a breaker bar so you don't get a hydraulic lock and possibly bend a rod with the starter motor. I witnessed that happening once.
I can't think of another reason for one cylinder to be cool with blow by at the same time. A cracked cylinder wall would introduce products of combustion into the cooling system where it could be detected but you have not had any overheating problems, correct?
When did you measure the manifold temperature, under load or idle.? Tight valve could drop the temp at idle.
Here is a site for testing Cummins B engines. The hole you drill would have to be larger for your increased displacement.Measuring Blow by, The Real Test For Internal Engine Condition - Seaboard Marine (https://www.sbmar.com/articles/measuring-blow-by-the-real-test-for-internal-engine-condition/)
Easiest thing to try first would be a fuel and crankcase additive. See below quote:
Problem: This is a CAT excessive blow-by issue caused by: diagnoseCause: Fuel, air, and moisture forced past the rings into the crankcase, or contaminated and diluted oil in the crankcase infoSSolution: Use Stiction Eliminator and Diesel Extreme Fuel Additive to free up both sides of piston rings. If the piston rings are worn out, they will need to be replaced.
Pierce
A bad injector will cause lower temp. in a cylinder. It can also cause it to use oil and smoke, because the cylinder is being flooded with fuel, washing the cylinder down. I did replace the injector, but it didn't solve the issue. From the way it was explained to me, if a ring sticks, and the piston goes down, then because of the natural tapper of the cylinder from wear, the ring can't collapse. This causes the ring to break. In my case, the bottom oil ring was broken,with a piece missing, but the top ring was messed up too (not broken). The top of the cylinder was really out of shape on one side. It had a 1/8" of wear in. It would have taken a 50 thousands bore to fix it, but they only make 40 thousand's pistons. The term "Throw away engine" came, because unlike most diesel engines, the 3126 does not have liners. In my case the block came out and was sleeved. I even re- used the piston. Chris
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: Protech Racing on November 30, 2018, 11:10:03 am
Sound like faulty top ring for the venting oil engine. Other places to look might be valve lash and cracked guide. Does this engine use rocker arms? A long time tight valve will destroy the guide and compromise the power of that chamber with bad seat seal. Bad guide or valve seal, usually shows as oil smoke in exhaust. A very slight leak at the head gasket can also show the same result of cool jug and blowby. It doesnt always push water. The bad turbo makes for white smoke as the oil gets vaporized and pumped out . You can run the vent tube into a catch can .
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: gracerace on November 30, 2018, 11:11:09 am
When you start a new thread on this maybe have the #6 and one of the other cyls. compression checked. If there is a big difference, you will know the problem. The low temp and blowby usually are the result of lack of compression either by scored cyl. or bad piston.
It isn't that easy to do a compression check, because the injector,rocker, and push rods have to be removed, then a compression gauge installed.After that you have to reinstall the rockers and push rods. It would take some sort of fancy compression gauge to do it, because the injectors don't screw in like a spark plug..
We actually used a rubber tip air hose, injecting 100 psi into each cylinder.We did this to each cylinder. #6 turned the engine over under pressure, just like the other cylinders did, and held as much pressure as the others. Granted, we didn't use a compression gauge, but all cylinders seemed the same. The blow by test is the most infallible. Easy to do, it just doesn't pinpoint the cylinder. At that point, it's time to pull the head anyway.
Chris
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: gracerace on November 30, 2018, 11:22:10 am
Sound like faulty top ring for the venting oil engine. Other places to look might be valve lash and cracked guide. Does this engine use rocker arms? A long time tight valve will destroy the guide and compromise the power of that chamber with bad seat seal. Bad guide or valve seal, usually shows as oil smoke in exhaust. A very slight leak at the head gasket can also show the same result of cool jug and blowby. It doesnt always push water. The bad turbo makes for white smoke as the oil gets vaporized and pumped out . You can run the vent tube into a catch can .
All good info...The injectors are under the valve cover on a 3126, so the O rings can allow oil into the cylinders. Still wasn't my case, I tried replacing those. It helped, along with a new injector for #6. Didn't fix the problem.Even sent the Turbo back in for inspection (it was just rebuilt by Borg Warner) they found nothing wrong,and rebuilt it again for free. I did have oil in the turbo, but it was just because of the bad oil consumption I was having.
The difference between Bob's and my issue is, mine didn't blow any oil out, only bad blow by. Ours was also using 1 quart of oil every 100 miles or less. In hindsight, it started out using less oil, but started having extreme blow by. I probably drove it too long with the issue it had.I was in denial! If Bob's turns out to be a broken ring,he may get by with just repairing the one cylinder with a new set of rings. Chris
Title: Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup
Post by: Pierce & Gaylie Stewart on November 30, 2018, 11:59:58 am
A bad injector will cause lower temp. in a cylinder. It can also cause it to use oil and smoke, because the cylinder is being flooded with fuel, washing the cylinder down. I did replace the injector, but it didn't solve the issue.
Yes, a bad injector will cause lower exhaust temps, especially at idle but does not usually go with increased blow-by. Stuck compression rings may not break, so may be treated in many cases by fuel and crankcase additives. In overhauling many diesels, I've never seen a broken ring with the exception of engines that have piston/cylinder galling from lack of oil changes.
Nothing wrong with parent bore engines and the term "throw away engines" does them a huge disservice. Mercedes used parent bore engines on their car diesels for many years. The Cummins 5.9 is a parent bore engine. With parent bore engines, depending on cylinder wear, they may be re-ringed, bored with oversized pistons or bored and sleeved. Boring or sleeving will give an engine that should last as long as new.
With liners, there are two types, wet and dry. Detroit 92 series 2-cycles and Cummins 8.3L, 855, N-14 Cummins engines are wet sleeve engines. Mercedes uses dry liners in their auto diesels now. With the wet bore engines, the liner can be replaced (Detroit) at home with a few simple tools without needing a press. The dry liner that Mercedes uses is pressed into place once the old one has been removed and since they stick up a few thousands above the block, a milling machine must surface them flat before the engine can be assembled and put into service. Wet liners use spacers of different thickness to bring the liner flush with the top of the block.
Wet liners have seals at the bottom and top so the seals may be prone to damage in the case of severe overheating.
Pierce
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: bdale on November 30, 2018, 12:15:38 pm
Wow. Lot's of good info. My feeling is, as several have mentioned, that it is probably a stuck ring. I don't slow idle much but that's the only thing that completely makes sense to me, given my current symptoms of white smoke in the crankcase but not at the tailpipe. I have run 2 gallons of seafoam through the last several tanks and have now added another 40oz to the crankcase, hoping it might help over the next several hundred miles. I'm sure that pulling the injector and directly treating the cylinder would be better, and I may try that eventually.
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: Bill Willett on November 30, 2018, 12:29:17 pm
Chris, can they pull the injector, and use a bore scope to see if the is any cylinder damage without pulling the head.
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: Pierce & Gaylie Stewart on November 30, 2018, 12:51:52 pm
While this is not applicable to the CAT in question, it's a good video for understanding how wet liners are removed (and replaced in the next video) by a simple tool. I think this engine is a Cummins as it has oil sprayers to cool the piston crowns. The video also shows the seals in question when the liner is pulled. Really excellent.
https://www.youtube.com/watch?v=MXd6-b1PQJ4
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: craneman on November 30, 2018, 02:26:30 pm
Nothing so fancy in a backyard rebuild. I made a tool to catch the bottom of the liner and pulled them out with a comealong.
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: gracerace on November 30, 2018, 03:05:23 pm
Chris, can they pull the injector, and use a bore scope to see if the is any cylinder damage without pulling the head.
You probably could. I actually had one I borrowed, but the camera was too big. It a pretty small hole at the bottom of the injector hole. It's tapered Chris
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: gracerace on November 30, 2018, 03:13:39 pm
Wow. Lot's of good info. My feeling is, as several have mentioned, that it is probably a stuck ring. I don't slow idle much but that's the only thing that completely makes sense to me, given my current symptoms of white smoke in the crankcase but not at the tailpipe. I have run 2 gallons of seafoam through the last several tanks and have now added another 40oz to the crankcase, hoping it might help over the next several hundred miles. I'm sure that pulling the injector and directly treating the cylinder would be better, and I may try that eventually.
Bob, if you do pull the injector, take extra care pulling the wire plug off the injector. They are brittle. I did fine the 1st time around replacing the O rings, but by the second time the 4 clips broke. There are repair plugs, but would be a hassle in coach. I did 4 of mine while the harness was on the bench clean. Chris
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: craneman on November 30, 2018, 03:23:42 pm
If you pull an injector this is the tool to use to check compression.
SKU : TU-15-43 - Diesel Compression Test Adapter for Caterpillar 3126 and... (http://www.langtools.com/sku-tu-15-43-diesel-compression-test-adapter-for-caterpillar-3126-and-3126b/)
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: gracerace on November 30, 2018, 03:44:34 pm
Just want to clarify for those following. Our engines are 3126's...or sometimes called 3126 'A'. They are a 2 valve one year only engine. The 3126 'B' is a 3 valve, completely different engine. They used that engine till Cat went to the C-7 The repair manual is totally different, especially in the head, injector, and valve train area Chris
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: bdale on November 30, 2018, 04:01:28 pm
Just want to clarify for those following. Our engines are 3126's...or sometimes called 3126 'A'. They are a 2 valve one year only engine. The 3126 'B' is a 3 valve, completely different engine. They used that engine till Cat went to the C-7 The repair manual is totally different, especially in the head, injector, and valve train area Chris
Hmmmm....I need to double check mine then. I always thought it was a "B". Probably not since we're only 2 build #'s apart.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: John and Stacey on November 30, 2018, 05:08:54 pm
Mine is also a 3126(A)...not the B. John
Title: Re: Cat 3126B Venting White Smoke, Consuming Oil
Post by: gracerace on November 30, 2018, 06:45:59 pm
Hmmmm....I need to double check mine then. I always thought it was a "B". Probably not since we're only 2 build #'s apart.
'B' didn't start till mid 98. Ours has the split inlet to the manifold. 'B' intake enters on opposite side as ours. I spent some good money on a 'B" CD manual, only to find out it's all different Chris
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bdale on January 13, 2019, 01:57:02 pm
I believe I've found the source of the problem that is causing my engine to vent smoke out of the crankcase vent tube. After much speculation, research, checking various theories and a lot of help from several people the answer was found in an engine oil analysis. It revealed high levels of various metals indicating ring & piston wear along with high levels of silicon. Dust! Checking the air filter confirmed that it has a few small holes, which seem to have been caused by water in the filter can.
Roger started a very informative thread on exactly this issue a few years ago. AIr Filter Failure Warning! Don't get Dusted! (http://www.foreforums.com/index.php?topic=25391.0)
From what I can tell, like his, my water may have entered during a major storm as I passed through Colorado last year. My symptoms did not show up until that trip. In the pictures, the water mark can be clearly seen on the end of the filter. The hole in my filter was smaller than his, and I'm hoping the damage is less as well.
I've now changed the air filter as well as the oil & filter. I'll also be looking into the air intake deflector that several others have installed. I'll send another sample for oil analysis in a few thousand miles and hope that the vent smoke stabilizes or gets better, not worse. That sample should show if the internal wear has stopped or is still progressing. I highly recommend Blackstone Labs for the oil analysis, by the way. They provided not only a great report with all of the relevant details and a personalized interpretation but were also very helpful in making recommendations over the phone. They gave some hope that this might have been caught early enough to avoid major engine work.
The duck bill drain on my filter can is in great shape but it's on the opposite side from the larger end of the cone filter. The cone is almost in contact with the canister at that end, and any water there will soak the filter. So, as Roger warned us all, check your air filters, especially if you might have ever had water in them.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Jan & Richard on January 13, 2019, 02:11:17 pm
Thanks for the update. Lets hope you caught it early enough that the damage is very limited.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bbeane on January 13, 2019, 03:58:18 pm
Hope you caught it soon enough. But me thinks broken/worn rings or cylinders.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Pierce & Gaylie Stewart on January 13, 2019, 04:52:17 pm
While our filter was wet and had partially collapsed, it didn't seem to have a hole in it. The new Donaldson is a far superior construction plus I'm changing the intake location so it can't pick up any water.
Pierce
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Chuck Pearson on January 13, 2019, 05:20:31 pm
Do your turbo vanes show any erosion, dusting will generally show up there.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Mike Leary (RIP) on January 13, 2019, 05:34:53 pm
Do your turbo vanes show any erosion, dusting will generally show up there.
X2....I've blown a couple of turbos, and the OP describes EXACTLY what happens when a turbo goes bad: white smoke, heavy oil use. Now, he's saying the smoke is from the breather, is the exhaust pipe clean?
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Caflashbob on January 13, 2019, 05:39:56 pm
Switched to Donaldson blue. Finer filtering. Not affected by water as far as I know
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bdale on January 13, 2019, 06:16:27 pm
Do your turbo vanes show any erosion, dusting will generally show up there.
I haven't specifically checked the turbo vanes. I did pull the intake hose from the turbo and it appeared clean inside with no apparent issues. It would seem that the kind of erosion that you're suggesting would come from a fairly long exposure to constant dusting. I "think" mine was a pretty limited event.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bdale on January 13, 2019, 06:25:52 pm
X2....I've blown a couple of turbos, and the OP describes EXACTLY what happens when a turbo goes bad: white smoke, heavy oil use. Now, he's saying the smoke is from the breather, is the exhaust pipe clean?
Actually, I don't think I ever said I'm getting smoke from anywhere other than the breather tube. The exhaust pipe does have dry, black soot but no more than normal. And no smoke of any kind or color from the tail pipe, except maybe a blast of black smoke at startup. I wouldn't necessarily categorize the oil consumption as heavy. Others have mentioned as much as a quart every 100 miles. I'm losing maybe a gallon or more over 6k miles. I've now calibrated my dipstick and I'll be watching that much closer over the next several thousand miles.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: ohsonew on January 13, 2019, 06:40:33 pm
Thanks for the reminder on the air filter. Hope your damage is minimal.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Mike Leary (RIP) on January 13, 2019, 06:45:48 pm
Actually, I don't think I ever said I'm getting smoke from anywhere other than the breather tube. The exhaust pipe does have dry, black soot but no more than normal. And no smoke of any kind or color from the tail pipe, except maybe a blast of black smoke at startup. I wouldn't necessarily categorize the oil consumption as heavy. Others have mentioned as much as a quart every 100 miles. I'm losing maybe a gallon or more over 6k miles. I've now calibrated my dipstick and I'll be watching that much closer over the next several thousand miles.
O.K., if you have a turbo seal gone bad, you WILL go through oil, big time. You will have a blue/grey smoke from the exhaust, and at higher elevations, LOTS of white smoke!
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Pierce & Gaylie Stewart on January 13, 2019, 07:45:11 pm
Actually, I don't think I ever said I'm getting smoke from anywhere other than the breather tube. The exhaust pipe does have dry, black soot but no more than normal. And no smoke of any kind or color from the tail pipe, except maybe a blast of black smoke at startup. I wouldn't necessarily categorize the oil consumption as heavy. Others have mentioned as much as a quart every 100 miles. I'm losing maybe a gallon or more over 6k miles. I've now calibrated my dipstick and I'll be watching that much closer over the next several thousand miles.
You can get a crankcase water manometer tool that will measure the amount of blow-by. A gallon every 6000 miles is less than a quart per thousand. Some have had success with a decarbonizer or flushing oil concentrate. Do a Google search for above.
diesel blowby tester cat - Penelusuran Google (https://www.google.com/search?ei=mdk7XLzuMMvisAWLx5CgBg&q=diesel+blowby+tester+cat&oq=diesel+blowby+tester+cat&gs_l=psy-ab.3..33i22i29i30l2.3549.4790..5191...0.0..0.113.441.0j4......0....1..gws-wiz.......0i71j0i22i30.Z1vef096lvA)
Pierce
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Kemahjohn on January 13, 2019, 08:15:55 pm
A quart per thousand miles is normal oil consumption in a diesel engine. Not excessive.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Caflashbob on January 13, 2019, 08:52:49 pm
8v92 used a gallon per thousand miles. Birds had a metered oil filler in the engine compartment.
My Lexus ls460 says above a quart in 600 miles to contact service.
Same car using 0-20 used a quart in 7,000 miles
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil - RESOLVED
Post by: bdale on April 07, 2021, 12:38:56 am
Updating to close this thread out for anyone that might have been following my engine issues.....
My Cat 3126 engine continued to get worse over time, burning 14 gallons of oil on my recent 2500 mile round trip to Q. See previous posts for the history but it was time for it to go. Last week Holt Cat in Longview Tx completed the installation of a rebuilt motor, and I re-lined the engine bay this week with 2 layers of Noico 80mil sound deadener and 1 layer of EZ-Cool insulation.
Very happy so far with both, although I'm having an issue with a low rpm idle that shakes the coach pretty badly until throttle is applied. They increased the idle from 700 rpm to 750, which helped but did not fully resolve the issue. I think it needs to go to 800 but they want me to run it this way for a while to see if it gets better on its own. So I'll give it 1k miles or so and see what happens.
So far I'm noticing that I don't lose speed or change gears as often on inclines but I'm not seeing any difference in MPG yet. I'm hoping that might happen as it gets broken in. But, I'm not burning or leaking oil so mission accomplished.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Chuck & Jeannie on April 07, 2021, 08:31:11 am
Engine bay lining looks great! Well done. ^.^d
As I'm sure you know, if the idle speed is set too high, the Allison will refuse to shift out of neutral (N).
Did they install fresh new motor mounts with the rebuilt engine? In one photo I think I'm seeing red urethane motor mounts. If so, these can sometimes be less flexible than standard rubber mounts, resulting in more engine vibration transmitted to the chassis. At least that's the way it worked on my old hot rods. 8)
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: John44 on April 07, 2021, 09:24:49 am
Good spot on the motor mounts,agree with above,rubber is better.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bdale on April 07, 2021, 09:54:06 am
Yes, all new motor mounts. And they may need to be changed if raising the RPM's doesn't resolve it. I'm pretty sure I used to idle at 800 though. Increasing the throttle pedal to 800 (measured on my BlueFire tach) does seem to be just enough to smooth it out and I've confirmed that the transmission will go into gear at 800. So, I'm thinking that will be the solution.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: jor on April 07, 2021, 10:09:55 am
Bdale, what is that box structure on the left side of the bay? Great job on the insulation. jor
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bdale on April 07, 2021, 10:17:05 am
That's the safe. The door is on the driver side of the bed pedestal.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Pierce & Gaylie Stewart on April 07, 2021, 10:31:23 am
bdale,
Talk to your shop to see if they rebuilt the injectors and/or injection pump. Unless the pump is putting out the same pressure, amount and at the right time for each cylinder, the idle will be rough. I used to send all the MBZ pumps to the shop to be re calibrated (and add fuel). An hour on the bench should do the trick.
Pierce
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Chuck & Jeannie on April 07, 2021, 10:37:11 am
Talk to your shop to see if they rebuilt the injectors and/or injection pump. Unless the pump is putting out the same pressure, amount and at the right time for each cylinder, the idle will be rough. I used to send all the MBZ pumps to the shop to be re calibrated (and add fuel). An hour on the bench should do the trick.
Pierce
They did install new injectors and a new (rebuilt) HEUI pump. I assume they calibrated it all properly. It's not really running noticeably rough though. Standing outside the coach you'd never know there was an issue. It's just that at the lower RPMs there's a lot of vibration being transferred throughout the coach. The cabinets rattle and you can feel the vibration all the way to the drivers seat. It's like it's hitting a harmonic resonance frequency or something. It all disappears completely when it passes 800 rpm and never comes back at any driving speed.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Protech Racing on April 07, 2021, 02:13:44 pm
The engine mount bolts may be over or under torqued .
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: gracerace on April 07, 2021, 08:51:54 pm
We are brothers from different mothers..........Want to race?
Chris
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bdale on April 07, 2021, 09:22:30 pm
Let's do it! I'm leaving for Biloxi Ms on Saturday. 1st one there wins.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Old Toolmaker on April 08, 2021, 09:38:03 am
It's just that at the lower RPMs there's a lot of vibration being transferred throughout the coach. The cabinets rattle and you can feel the vibration all the way to the drivers seat.
So, you've gone from a tired engine to a brand new engine. From tired engine mounts to brand new, and trust me you'll never match the mounts that came from the factory.
Fun fact, once upon a time engines were bolted directly to the frame. W.O. Bentley tried to hide the rubber engine mounts from a sense of shame on the Cricklewood Bentleys.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: dsd on April 08, 2021, 10:06:37 am
The original mounts also had a lifetime of use and if had not failed were as soft as they possibly could be. The manufacturer go to great lengths to match up correct mounts to provide long quiet service. Can be difficult to duplicate. Scott
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Old Toolmaker on April 08, 2021, 11:28:46 am
The original mounts also had a lifetime of use and if had not failed were as soft as they possibly could be. The manufacturers go to great lengths to match up correct mounts to provide long quiet service. Can be difficult to duplicate. Scott
When I re-built the engine in my 1950 Chrysler, I was happy to be able to buy re-production engine mounts even with the disclaimer that I "might feel more vibration."
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: bdale on May 13, 2021, 12:34:47 am
Updating to close this thread out for anyone that might have been following my engine issues.....
My Cat 3126 engine continued to get worse over time, burning 14 gallons of oil on my recent 2500 mile round trip to Q. See previous posts for the history but it was time for it to go. Last week Holt Cat in Longview Tx completed the installation of a rebuilt motor, and I re-lined the engine bay this week with 2 layers of Noico 80mil sound deadener and 1 layer of EZ-Cool insulation.
Very happy so far with both, although I'm having an issue with a low rpm idle that shakes the coach pretty badly until throttle is applied. They increased the idle from 700 rpm to 750, which helped but did not fully resolve the issue. I think it needs to go to 800 but they want me to run it this way for a while to see if it gets better on its own. So I'll give it 1k miles or so and see what happens.
So far I'm noticing that I don't lose speed or change gears as often on inclines but I'm not seeing any difference in MPG yet. I'm hoping that might happen as it gets broken in. But, I'm not burning or leaking oil so mission accomplished.
Vibration issue solved. One of the engine mounts was installed incorrectly. It was not properly centered and seated in it's hole when they bolted it down, which pinched the mount to the point where the metal on each side of the mount was rubbing at lower RPMs. As the RPMs rose, the torque rotated the engine enough to separate the metal-on-metal contact. Turned out to be a very easy fix that cost a lot of time and frustration. Happy to have it all worked out now.
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: gracerace on May 13, 2021, 09:28:19 am
Vibration issue solved. One of the engine mounts was installed incorrectly. It was not properly centered and seated in it's hole when they bolted it down, which pinched the mount to the point where the metal on each side of the mount was rubbing at lower RPMs. As the RPMs rose, the torque rotated the engine enough to separate the metal-on-metal contact. Turned out to be a very easy fix that cost a lot of time and frustration. Happy to have it all worked out now.
You're headed for many years of happiness. 13K miles and counting for us, not one drop oil on the ground, and engine clean as a whistle.Lots of power. Even with th investment of the engine, you have a steller coach. You might read my post about oil if you haven't. Stay with straight mineral oil in my opinion. Delo seems to be the favorite. Hopefully they won't go to blended.
Mobil Delvac 1300 Oil In Our 3126 Cat (https://www.foreforums.com/index.php?topic=42310.msg423747;topicseen#new)
Cheers Chris
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: Doug W. on May 13, 2021, 11:02:15 am
You might read my post about oil if you haven't. Stay with straight mineral oil in my opinion. Delo seems to be the favorite. Hopefully they won't go to blended.
Mobil Delvac 1300 Oil In Our 3126 Cat (https://www.foreforums.com/index.php?topic=42310.msg423747;topicseen#new)
Cheers Chris
Delo 400 LE SAE 15W-40 exposes the semi-synthetic myth (https://www.fleetequipmentmag.com/delo-400-le-sae-15w-40-exposes-the-semi-synthetic-myth/)
Title: Re: Caterpillar 3126 Venting White Smoke, Consuming Oil
Post by: gracerace on May 13, 2021, 12:44:24 pm
Delo 400 LE SAE 15W-40 exposes the semi-synthetic myth (https://www.fleetequipmentmag.com/delo-400-le-sae-15w-40-exposes-the-semi-synthetic-myth/)
Excellent read Doug. Verifies what I thought. The whole deposit thing is what's important with Cats. Probably why they have ring issues. That is why I change my oil so often. With the Cat HEUI pump, the oil condition and velocity is really import, I think more so then the Cummins. Lastly, I truly believe blends break down too quick, hence the heavier oil usage. Interesting they try to sell you on extended oil changes with blends. Chris