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Topic: Caterpillar 3126 Venting White Smoke, Consuming Oil (Read 1169 times) previous topic - next topic - Topic derived from CAT 3126 Coolant in O...

Caterpillar 3126 Venting White Smoke, Consuming Oil


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.

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #1
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

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
Pierce,  Gaylie and Koda
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #2
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
John and Stacey Smith
Motorcade NO: 11973
1997 U295 CSGI 40'..Build No. 5036      
920 Watts on the roof..CAT Power w/fuel Inj. Programmer
2021 GMC Sierra AT4 1500
EX..2015 Jeep Wrangler Sahara
Ex 1990 U280 RSAI 36'..Build No. 3638

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #3

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.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #4
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

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
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #5
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 .

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #6
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
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #7
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
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: "Cat 3126B Venting White Smoke, Consuming Oil"Re: CAT 3126 Coolant in Oil: Followup

Reply #8
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
Pierce,  Gaylie and Koda
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #9
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.

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #10
Chris, can they pull the injector, and use a bore scope to see if the is any cylinder damage without pulling the head.
Bill&Doris 97 U270 36'
University of Parris Island Class of 66
Semper Fi   Build# 5174 MC#17094


Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #11
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
Pierce,  Gaylie and Koda
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #12
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.
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #13
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
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #14
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
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #15
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...
1999 40 ft. U-320 wtfe build 5563 Chuck & Lynda's "Rollin' Inn"  2030 watts solar
prev. mh's 71 GMC 5 yrs. 73 Pace Setter 1 yr. 78 Vogue 5 yrs 81 FTX 40ft all electric 18 yrs. 1996 Monaco Signature 3 yrs.
2014 Grand Cherokee Overland
Dream as if you will live forever. Live as if you will die today.  James Dean

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #16
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
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #17
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.

Re: Caterpillar 3126 Venting White Smoke, Consuming Oil

Reply #18
Mine is also a 3126(A)...not the B.
John
John and Stacey Smith
Motorcade NO: 11973
1997 U295 CSGI 40'..Build No. 5036      
920 Watts on the roof..CAT Power w/fuel Inj. Programmer
2021 GMC Sierra AT4 1500
EX..2015 Jeep Wrangler Sahara
Ex 1990 U280 RSAI 36'..Build No. 3638

Re: Cat 3126B Venting White Smoke, Consuming Oil

Reply #19
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
Chris and Tammy White  CDA Idaho
1997 U295 36' 3126 Cat 300 HP Build # 4998 
Former Foretravel tech & RVIA certified tech
Former owner Custom Satellite home/RV satellites 
Former owner Vans LTD  van conversions
Unemployed, panhandler, drag racer NHRA #6348

Re: Caterpillar 3126 Venting White Smoke, Consuming Oil

Reply #20
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!

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. 

Re: Caterpillar 3126 Venting White Smoke, Consuming Oil

Reply #21
Thanks for the update. Lets hope you caught it early enough that the damage is very limited.
Jan & Richard Witt
1999 U-320  36ft WTFE Build Number: 5478
2008 Roadtrek Adventurous RS Sprinter
2011 Jeep Wrangler Unlimited
Jan: NO5U, Richard:KA5RIW
”summer bridge”


Re: Caterpillar 3126 Venting White Smoke, Consuming Oil

Reply #22
Hope you caught it soon enough. But me thinks broken/worn rings or cylinders.
Bruce, Linda, and Macy
Zoey RIP 1/20/19
1999 U295 40' build #5400
2017 silver Jeep Wrangler, 840 watts of solar on top
Moving around the country

Re: Caterpillar 3126 Venting White Smoke, Consuming Oil

Reply #23
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
Pierce,  Gaylie and Koda
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof

Re: Caterpillar 3126 Venting White Smoke, Consuming Oil

Reply #24
Do your turbo  vanes show any erosion, dusting will generally show up there.
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS