well i think i found the reason why the head gasket was blown on the gv i just saved from the wrecking yard. i hope that everyone at least checks the back side of your rads to make sure this doesnt happen to you.
Actually, I suspect that is the FRONT (front of coach) of the radiator. And if there is a CAC (charge air cooler) installed it will be in front of the radiator and the dirt will be on the front of it.
A very common and well known issue with rear radiator coaches of all brands. You are basically a "vacuum cleaner" driving down the road. The dirt on the road is stirred up by the passing of 6 tires and your 36' coach. That air passes over the hot (and sometimes oily) rear axle, transmission and engine before the large fan sucks it up and pushes it through the radiator (or CAC and then radiator). The CAC or radiator then acts as a "filter" removing much of the dirt.
You need to clean the front piece of the cooling system at least annually and often more than that.
Brett
i agree with you on that as i see this alot at the radiator shop i work in. and the biggest tip i can give to every one is change your coolant every 2 year and save your self a big headace and cost
I agree, changing coolant is important-- basically every 3 years on "low silicate for diesel coolant with SCA" and every 6 years for one of the OAT based extended life coolants. Most of the OAT based coolants need a "booster" added after 3 years, but no SCA testing/adding and 6 year life.
But, this is totally unrelated to cleaning the OUTSIDE of the CAC or radiator.
Brett
Brett -
Several years ago I did some researching on "Extended Life" and OAT Coolants, and all those I looked at said "6 years" IF you also put in an additive package at 3 years. I discovered this "IF" at the 5-year point so I changed out both the Cummins and the Kubota coolants.
Look out for the fine print!
That happened to the previous owner of my U225. New rad and in-frame rebuild resulted on the 5.9 Cummins, setting him back $12.6K.
Is there a "correct" way to keep the rad/aftercooler clear? I do see an oily film and some dirt, and it strikes me that blowing back through (ie from the back of the coach) would work best. Water by itself I don't think will do the job; perhaps some engine degreaser spray on the front to first soften/loosen the dirt? Any thoughts?
Steve
Your on the right track. I used to use two cans of Oreilly's Engine Degreaser from the inside under the bed each year. When the radiator was pulled both the CAC and the radiator were very clean. The hardest part to get to is behind the fan cowling. You have to be a contortionist to get back in there with the spay.
I also brought a garden hose in through the bedroom window and sprayed down the CAC from the inside twice a year with just water and blew high pressure air through the radiator from the outside occasionally. Everyone who has a rear radiator needs to stay on top of keeping it and the CAC (intercooler) clean.
Thanks Kent.
It was actually behind the cowling that the original rad was plugged the worst. Thinking that perhaps the cowling should be pulled once a year for a real thorough cleaning in there. Am also thinking a pressure washer would probably be a bad idea, with a good chance of bending fins. Solvent, garden hose, and compressed air (or my backpack blower) should do it. Strikes me that you need to be doubly diligent if traversing a lot of dirt roads or dusty areas, especially if you're seeping oil anywhere.
Steve
Steve, you are correct regarding the high pressure water. I was warned many times to use only a garden hose. Once you have it clean, its pretty easy to keep clean.
If there are any oil leaks get them fixed.
There will be two different answers here depending on whether the coach (as most are) ts equipped with a CAC (Charge Air Cooler-- aka Intercooler, aka After-cooler. All the same thing).
If no CAC, that means your "cooling system" is just the radiator and therefore one "layer" thick. Clean from the back-- reverse direction of air flow. This should knock the crud off the front of the radiator unless very clogged up in which case you may have to clean from the front as well.
BUT for the vast majority of those with a rear radiator, you also have a CAC. This means the "cooling system" is TWO, repeat TWO layers thick. It can not properly be cleaned from the back only. Enough PSI to go through the radiator, air gap and CAC with enough power to knock crud off the front of the CAC would be enough PSI to bend fins on the radiator. Yes, clean from the back as well, but the vast majority of the cleaning will be from the FRONT. Note, the fan blades sling the dirt to the perimeter, so you want to verify that the perimeter is as clean as the center.
And many CAC's are aluminum, so be very careful not to use harsh cleaners that are not compatible with aluminum.
And, if your crankcase breather (aka slobber tube) has not been extended to behind the air intake for the cooling system, DO SO. That way you are not putting oily vapor on the cooling system which materially speed up the clogging process.
Brett
i used simple green and the soft spray at the car wash. but i had mine out and on a trailor
I had flushed out the radiator and CAC a couple times recently with a garden hose. Today, I removed the rubber cover across the bottom and did a thorough cleaning, and discovered that I had missed a lot. I pulled probably a gallon jug, maybe two, worth of leaves, feathers, gravel and dirt. I flushed thoroughly with a spray of Simple Green and a garden hose. It took a good 1/2 hour of constant flushing until the water started to flow clear. I had no idea I has missed so much stuff - it was not visible from the front, back or underneath, until the guard was removed.
I have a streak of junk in my driveway that came out!
oldMattB
Do the side mounted radiators require this same cleaning approach and frequency?
Any radiator at the rear of a vehicle picks up a lot more dirt from tires and low mounting than one higher up in clean air in the nose. Oil/fluid deposits from engine components can speed up the process. Especially true if you spend any time on gravel or dirt roads. Driving in the rain can also bring a mixture of debris to the bottom portion. You may not realize it is partially clogged until you head up that grade in hot weather. Not that much trouble to check.
Guys,
He has a 1994 U240. It IS a side radiator.
Picture driving down a road in the rain. The side of the coach has some mud on the side. That huge fan has pulled tens of thousands of cubic feet of that dirt and water ladened air through the CAC and radiator. A lot of that moisture evaporates when it hits the hot metal. The dirt is left. Does a side radiator need as much cleaning as a rear radiator. Does it need an annual cleaning-- YES. And, yes a trip to Alaska calls for several cleanings.
Brett
Brett,
Do all U300 Series have the rear radiator or did the later models have the side type ? I only know the 89 U300 with the 6V-92 300 Hp, with the rear radiator.
I had the rear radiator on the MCI when I put the 12V-71 in it, as the origional cooling setup was borderline with a 8V-71 @ 280 HP, Removed all of the original setup, installed the 5' X 6' radiator across the rear, using a pusher 54" fan, that worked until I went crazy with the 800++ HP, had to add the windshield washer fluid spray syaten, that worked super good, did not need a lot of fluid, maybe 1 qt. on a 5 mile mtn. Oh what joy.
Wish I could have had the space for a side mounted radiator setup, that is much more effective than the rear setup.
We found the same large quantity of debris, leaves, twigs, etc. between our charger air cooler and radiator with oil cooler in between. It was shocking and I think most stuff was stuck near the bottom. Mirrors and lamps helped see what was in between coolers.
We removed outside grill and one long side of the bottom conveyer-belt material and used a hose with a short tapered nozzle that looks like miniature fire hose nozzle.
After several hours of moving hose top, sides, bottom and again and again more stuff kept coming out.
When we were done, I used spray yellow insulation to seal the many gaps around the conveyer belts to force all air to flow only through the outside grill. Black spray paint hides the yellow color of hardened foam. The biggest advantage of this sealing is improved cooling as warm air exiting the radiator is not re-cycled by being sucked into the gaps around the radiator.
We put a piece of hardware screen cloth behind the outside grill to keep larger debris out, like cut grass and leaves. I think that when we drive slowly along a driveway that just had is side grass cut, the radiator fans act like a vacuum cleaner sucking the loose stuff into the side radiator.
Mine looks very clean and no sign of any "garbage" but I think I will heed the posts and have a go at cleaning. I recently had the left rear fibreglass panel off to do the muffler removal and it was very simple to do and went back perfectly with no proof of ever being off so I may just take the rad side off as it may give me a better chance to clean properly. I like the idea of screen on the back of louvres that Barry mentions doing.
John
Do. Ours was flushed from the inside and outside twice in the last 1,000 miles, and none of the junk or dirt was visible. I was amazed how much stuff was in there, and how long it took to flush it out.
oldMattB
Well am I glad I decided to look at the Rad etc to clean it even though it looked good. I took off the louvred cover and washed it from front and rear using Simple Green as noted and to get into the fan area I used a long brake line type of wand that fits onto a spray gun unit I had for undersealing my vehicles with "wax oil". This did a great job then I noticed that the small cooler for Trans' I gather was touching the outside of CAC fins as the 2 top holding bolts had come loose. Well as you will see in the photos I have a nice cut in the aluminum gallery and I will have to clean it all up good as I may have another caused by the a screw above this. Now my question to all you brilliant people out there in cyberspace is it ok to just seal the hole with something like fibreglass or?? as there is no water going thru, or something else. I will await the info
John
John,
The CAC is an air to air intercooler, so no liquid. BUT, a leak will allow turbo boost to leak out! If you have a boost gauge, what does it read (as compared with spec). And, I would drive the coach by a radiator repair shop for their recommendation on the proper fix. The CAC works under 25+ PSI, so it needs to be air tight! Loss of boost means less HP and less MPG.
Brett
Thanks Brett, I just knew you would be onto it right away. I have a boost gauge as there is a Banks Stinger on the 350 Cummins, but not sure what I should be getting as far as pressure.
I think I will clean it up really good and use a 2 part epoxy that is extremely tough (3M) to repair it with.
What do you think. I have not got the bus insured at present but can if needed, and the other option is to remove the fibreglass panel on the end and take the CAC off completely.
John,
With the Banks system, check with them as far as correct max boost. You could also have someone rev the engine (in neutral) and put some soap bubbles on the area to see if there is a leak.
I would NOT use epoxy or other home-remedy without consulting a radiator shop-- they do this for a living. If it is leaking, a good photo could give the shop enough info to give you advice. Be sure to verify that it is aluminum vs steel (use a magnet).
Brett
I have decide to take that panel off and take the CAC right off and do as you suggest. I will check but I am sure it is Aluminum.
Thanks again Brett
John
On my 8.3 mechanical with Banks, max boost was about 28#. They can tell you what your ISC is regulated to.
well almost there as I have the side off and now to take off the CAC. I will then take it to the experts on Tuesday.(holiday weekend here) Lots of leaves dropped down and now I can give the whole thing a REAL good clean. Thanks again Brett for convincing me.
John
John, Did the screws that hold the trim strip on also hold the fibreglass panel on ? I THOUGHT that the trim strip would have to be removed to get at the screws that hold the fibreglass on. I hope its that simple.
Gary B
yes Gary you first take off the trim strip then there are 3 screws holding the panel in place at the top and some down the left hand side of the small door behind tyre. The panels come off easy and I had taken the other side off a few weeks ago to remove muffler as with my bad back I could not crawl under. Lots more room to work as well.
Now I have the CAC off and seperated the coolers and there is a fair amount of debris between them all so actually this is great to be able to clean. Now have to wait for the repair next week. I had a tough time moving things as I have had a cast on my arm and wrist since sunday. Tore some tendon and muscle !!! Ah well its off now
Howdy John,
thanks for this...Great photos and descriptions...I'm moving this project up on the "to do list".
Good Luck with your arm and wrist. Dave Abel
regarding this subject, I would suggest to all that have same set up for rads etc, to check that they do not have a similar problem that I found on ours. They are most probably all mounted the same and if the bolt came loose on mine it can happen to others too. Look thru' the grille and make sure that the small cooler rad that sits at top of CAC is still held clear (gap is about 1 1/2" from CAC). I did not notice the problem till I took off the grille but it can be seen thru it. I strongly advise all to check it out, or you will be doing what I am.
John
Well I decided to take it too my local Aluminum welding shop who does marvelous jobs (I am learning from him) and he said that he would not touch it as he has tried before and due to thin wall and dirt inside it just blows bigger holes in !! So I have to see what the rad shop says ( closed today) and I may just fininsh up doing it myself with epoxy as I thought first. I have contacted FT to see what make etc and replacement cost. Good job I have time on my side. Brett, any leads on replacement make from you??
John
Just pulled the grill off ours to clean the CAC and radiator and check bolts, and discovered both top bolts holding the CAC in place were loose or out! Bolts for the other cooler were tight. Important to check them periodically!
I was at the coach today replacing a belt tensioner, and decided to take a peak at the radiator. I found that it was possible to get a bit of a look between the CAC and the radiator from both the front and rear. With the door behind the wheels open and by moving some of the rubber aside and using a small flashlight, I could see a few leaves. Not enough room at the rear with the engine door open to get my head in there, but with a mirror I could see some grass. All of it was down near the bottom and not nearly as much as in John's pictures. I haven't had any overheating issues on long climbs, so I'm not in a big hurry to clean it, but someday I will. Over a year ago, I found that one of the CAC mounting bolts had fallen out, but it wasn't lost, still on the piece of rubber below the CAC, so I reinstalled it. Sort of a puzzle as to how the debris gets between the radiator and CAC. I'm guessing it first lands on the CAC, then when the engine is stopped it falls down onto the piece of rubber. Next time the engine is started it gets sucked up behind the CAC and onto the radiator.
the reason I said for all to check their units for loose bolts etc is because the way FT have installed them into a frame surrounding the rad' it gives only about 1 1/2 threads to hold it all as the metal there is 1/8 thick !!! not a good situation at all. You may be amazed at how they have even stayed somewhat tight after many miles and bumps. This comment of mine to check the bolts is not a lame one as I feel there are many units out there getting ready to come loose. Dave has already found out by my posting it. When replacing or tightening them make sure to use Locktite on threads.
I had an e-mail from FT today saying they (CAC coolers) cannot be repaired so I whent about it to see if I can prove them wrong. I have just finished using a Devcon metal filler and alum'n little backing peices and will wait till morning to see what I think. I figure if it does nor work in a few months or so I will have all the info needed by then to replace it with new, and for $65 cost of filler it may just work. This stuff is machinable so has to be good. I will post pics later.
John
John, Most radiator shops can repair and test for leaks not only radiators but also the CAC, or after coolers, most CAC units are aluminum and easy to repair. A new updated unit is costly, CAC units come in a few versions, some better than others, meaning better air flow and a better cooling output.
FWIW
well after having a dissapointing day trying to get it fixed I set about my own repair as noted earlier in my post. FT say it cannot be fixed and talking to a rad shop here and a couple online in your USA they say a new core will have to be put in. The Al shop here said the problem with trying to weld is the carbon deposit on the inside causes a blow back and will create holes bigger than before. He is a very good welder and only does Al work and he would not touch it.
So, I have done what I feel will fix it (but does not look as neat right now) as I am leaving it till morning to really set up and then I will set about filing etc to improve the looks. FT have not got back to me on a replacement price ( they are 3hrs ahead so that will be a factor). I am going to flush it out and first before fitting it and a few mods on the brkt that caused all this mess. Here are my fixes !!!
John, Sorry to learn of the problem, after your sure it is fixed, I would put 30 psi air in it to amke sure it is holding and no other holes/lleaks.
30 psi is the min amount, I would like to see more, about 35, the MY ISM had 26.5 before any mods, with resonator ,it was 29 and with the 500 rating it is now 33, that is the most I have seen on the dusplay, briefly.
Good luck
The company that makes them is in Corpus Christie - Atlas Radiator - 824 N. Chaparral St 78401. I have the blueprint for the radiator and CAC assembly. The CAC part number is 910113. It cost me about $1400 five years ago. You can review my posts on the subject. The CAC is the same now for Unihome and Unicoaches.
Here is the spec sheet. I emailed a copy to Barry Beam.
Several years ago a company was advertising on TV an aluminum solder by sealing holes in the bottom of an aluminum soda can. It might work in a situation like this. There are many youtube videos of the process. Here is one Durafix - 4 (http://www.youtube.com/watch?v=UWb09Ogf-rU#) If the epoxy repair can not stand the heat, you can probably burn it off and try the solder repair. The technique seemed to rely on the use of a stainless steel brush to get rid of the aluminum oxide just before applying the solder. I have no idea if this is possible, but might be worth a try.
Jerry that video is great and my neighbour (welder etc) told me he could repair it doing what you have shown, but I was sceptical and did not want to try it and have a further problem !!!! He has worked in the Vineyard business for many years and told me that he could "weld" even aluminum foil by this method and has repaired miles of thin irrigation lines just this same way.
I also got an e-mail back from Devcon the makers of the steel putty I used and their Tech said it would be fine as long as no liquids are present as the one I used does not fair well in liquid. It did not say that on the the label but as we know it is only hot air in CAC. So hope all is going to be well. One thing about were the damage is, is that should this not last too long I can just remove grille and get at it again.
Thanks Dave for the info on supplier etc
John
Well I did a water fill test and no leaks then made up an air pressure test system and on one end a gauge an the other air line. I left it at 20lbs for a bit then cranked it up to 40 lb for a while then 45 and left it at that. There was no drop at all in 15mins so I concluded it a success. Now to put it all back together. I will be keeping my eyes on it for a while while running the coach.
woohoo! Beats a couple of grand and a two week wait!
I agree on the woohoo, and John, I would make real sure you have good hose clamps and are snugged up real good and proper, installing a second right beside the originals would be great also. It is no fun when a hose gets blown off, not only does it get real smokey, but it can be real tuff to get the hose and clamps back on nice and tidy and tight along the side of the road.
ALSO, regarding the repairing your aluminum CAC, and the guy claims it can not be done, That reminds me how some mechanics can not fix anything with everything, while most mechanics can fix anything with nothng or very little.
You gotta laugh sometimes.
FWIW
John,
Thank you for taking the time to document this repair. Excellent information and a great job!
Rad and CAC back on so I started her up. Runs good and no leaks anywhere after doing leak tests. Will not know till I get on road for a couple days to see how changes affect things (muffler out and now the CAC)
I got a reply from Atlas in C Christi on replacement one as they sell them as Dave H mentioned. 6 week wait and $1550 plus taxes and shipping. SO, I gather with labour and parts I may have saved myself around $2400 !!! I have full confidence in this repair now. While the side panel is off I am going to do what Barry mentions in his post about sealing off the surrounding areas so the air is forced to go thru; the louvreed panel. I am going to get some ind' belting and cut to fit down sides and then attatch it to the bottom pce so it is a complete unit. This should keep all the crap out. I will post pics in case someone else feels like doing it.
By the way FT Parts still have not come back to me with a price on the CAC, and that now is a few days ago I asked !!!
This has been a very interesting discussion. So much so that I decided to have a look at the passenger side radiators on our 2003, 400 ISL coach. Below is a photo of the stacked radiators. Can someone identify the radiators/heat exchangers that I can't.
A....?
B....this must be the intercooler or charge air cooler given the plumbing from the engine
C...? Can't see this very well, but it is smallish in size and sits between the main engine radiator and the intercooler
D...This is the back radiator and must be the main engine radiator
One interesting thing.....I can't see where debris can accumulate in this setup. There is good access to the bottom of the first three layers. There are even some holes in the bottom covering to let anything that might get below the main radiator to pass out of this space. Is this a different design than the earlier coaches? I checked all the bolts and everything looks secure.
Thanks in advance for any input.
George,
A is oil cooler for tranny
B. Is CAC ( intercooler aka Charge air cooler)
c. Radiator
This is a nice setup, much easier access than mine.
Gary B
i thought that "A" was the oil cooler for the engine. At least on mine the tranny cooler is located behind the radiator fans and is a cylindrical unit with four hoses, 2 for coolant and 2 for tranny fluid.
George,
You are so fortunate that your radiator is so easily accessible, and being accessible makes it easier to clean. Our grill is riveted in place. When we were at Xtreme last year I talked to Rance about replacing the rivets with screws, but that got forgotten.
George your layout is the same as mine but it would have been nice to have the flip up panel. I had to take a side panel off to get at them. The cooler that is between the CAC and main rad is same as well and right now I am not shure what it is for so that makes 4 units the same as mine.
I have concluded that all the crap gets thrown up from the rear duals and that is why it can get up between them all. I have now framed in around the rads with conveyor belting cut to fit around CAC and abutts the fibreglass outside panel and the sides are fastened to the piece that goes across the bottom making a sort of frame. This should address any problems that were there. My louvre panel now will be screwed on instead of the rivets for ease of removal. I put spring clips on the fibreglass panel that take 1/4- 20 screws
John, I like your thinking, as I have the 01 320 with about the same setup with the rivets holding the side grille on. When I get to Xtreme this fall, I need to ask if they have a slick way of making it a hinged door, or I will use the screw method in place of the rivets.
Also like the belting, know the local Tractor Supply stocks a good belting selection.
ALso glad you took it to 40 psi.
So far, my conversion to 500 hp is holding up well, no heating issues and keeping good intake pressure/boost.
Cheers
Dave M
Dave, I actually took it to 45lbs for 30 mins.
You know, I may just work on changing that grille to hinged. I will figure how to do it then if I do it I will post pictures. It might be next year before I have the time as there are lots of small jobs to do here and I have to build an outside tool storage shed as Ruth is fed up having to leave her car in the driveway as I have tools everywhere !!
John
Ferlix, You may be right about the engine oil cooler. Sometimes in my dotage I forget that even though these are all FT's they are also all different. :)
Gary B
Well this is hopefully my last post on this subject as all is done and who would have known it had even been off. I am pleased with the result and really glad this topic was started as I would most probably have not looked at it in the first place and that would have caused more headaches later.
Yes, I do not have a lift up door. The CAC is on the outside and the other cooler/s are between the CAC and engine radiator. I'm not sure how many coolers or heat exchangers are between the CAC and radiator as I have not removed the CAC. Grill is held in place with 6 Phillips head SS sheet metal screws. I replaced an assortment of screws with larger ones of the same size, so it didn't come from the factory that way.
On ours (99 U270, ISC) there is an outer small cooler which looks like it's the cooler for the hydraulic fluid, then the CAC, and then a small cooler between the CAC and the radiator, which I'm guessing is the engine oil cooler. Our transmission has the standard cylindrical heat exchanger that transfers trans heat to engine coolant.
Someone mentioned that they installed a cooler on the return fuel line, and I think that when I do that I'll put it in front of the CAC below the hydraulic cooler.
Dave.
That it where our fuel cooler is located and it works well there. Keeps fuel return close to ambient temp.
Pamela & Mike
That's what I want to do too! Haven't ever measured the temp of the fuel tank after a long trip, but I bet it can get pretty warm from the hot return fuel, and unlike trucks, our tanks are somewhat insulated.
Not quite sure I understand. Why would you want to do this? Cool fuel work better ?? ..Why would Foretravel/Commins not do this if it made any sense? Just questioning?,,,, FWIW
Modern diesel trucks seem to commonly have fuel coolers, and I read in one of the diesel forums that Cummins is requiring them. Now modern diesels generate lots more heat at the injectors than our older ones, but I can imagine that in 100+ deg heat, the fuel in our tanks wouldn't cool much before going back to the engine, and that could be trouble.
One of the arguments made for maintaining 1/4 - 1/3 tank of fuel in our coaches (in addition to not having to prime the fuel system if you run out) is that a smaller amount of fuel in the tank will heat up more quickly from the returning fuel, sending heated fuel back to the injectors, getting hotter, etc., so better to have more fuel remaining in the tank to act as thermal mass.
google 'diesel fuel cooler' and your get mixed answers. Newer diesels are adding coolers on the return lines. Here is a link to install pics of a Flex-A-Lite trans cooler as a fuel cooler for a Jeep CRD. I particularly like his way of protecting his lines from abrasion. So simple, yet I had never considered it! Picasa Web Albums - Steve Sharp - CRD CP3 Fuel ... (http://picasaweb.google.com/116739968652731154172/CRDCP3FuelCooler?gsessionid=yE92Sh3rxTDLGuGPRLv4eg#5238623849736497122Here) is the link that references the pics. Fuel Cooler great asset on Common Rail - TDIClub Forums (http://forums.tdiclub.com/showthread.php?t=235172)
I belonged to the TDI club for several years when I had my 04 Jetta. Savvy people!
George,
We should have the same layout .... so here is what I think they are:
A -- Fuel Cooler
B -- Charged Air Cooling System (C.A.C.) (all those 4" diameter pipes you see in the engine compartment)
C -- Hydraulic Fan System Cooler
D -- Radiator
The transmission cooler looks like a tube muffler. Its located behind the cooling fans down at the base of the coach. It gets its cooling fluid from the radiator as well. If you look in the engine compartment at the very lower right rear side of the radiator a 2.5" output goes right to the trans cooler. I tried to take a picture but its not in a great spot.
Wow! Nice job John... I missed this post somehow. So without recapping the whole thread, you drilled out the rivets around your grill and replaced them with screws for easy removal?
Don
For those with older coaches with the grills installed with screws directly into the FG body panel, a good option to allow the grill to be removed and reinstalled with no danger of the screw stripping the fiberglass is to affix a strip of aluminum the length of the grill and fit inside of the FG into which the screws are screwed. Hold in place with epoxy or flush mount screws through the FG (two are plenty per length of aluminum strip.
Use the old holes in the FG to drill and then tap the aluminum strap. Paint the heads of ss machine screws while to match coach sides/original screws and use machine screws into threaded aluminum to secure the grill. A little anti-seize on the screws minimizes galvanic corrosion. Makes removing the side grill on our coach a 2 minute operation with no fear of stripping the FG into which the screws tighten.
Brett
John, thanks for the photos and the play by play. If the epoxy was aluminum filled, I don't think you will have any problems due to heat. Our aluminum filled epoxies would take up to 700 degrees F.
Also, I admit I don't know a lot about diesels but I thought that air going through the CAC was pre-turbo. If so then there shouldn't be much pressure in the CAC. Does the air go through the turbo then into the CAC and then to the intake manifold?
Kent,
The order in the air system on any diesel with these components is:
Air intake
Air filter
Turbo
CAC
Engine Intake Manifold
The purpose of the CAC is to take hot air (sometimes over 300 degrees F) and reduce it to near ambient temperature. Cooler, denser air gives better MPG, performance and less emissions.
Brett
Thanks Brett! How much can a CAC cool 300 degree air? I can't imagine it would take it from 300 to ambient.
Yes, it can.
Look at the surface area of the CAC and the CFM of air going through the whole cooling package.
BTW, two things lead to the 300+ temperature coming out of the turbo: heat transfer from the exhaust in the exhaust side of the turbo-- can be over 1200 degrees F. And, from the Ideal Gas Law, if you compress a gas with all other variables being constant, temperature GOES UP. (PV-nRT).
So, a clogged cooling system can loose you performance and economy long before you see an overheat on the coolant, as higher intake temperatures hurt both.
Brett
Brett, If I set my alarm on the VMS what would the temp be for a safe margin for the intake air? thanks jc
My intake manifold temp was 120 starting out, topped 131 in some hills coming into Atlanta on 475 today...
On my VMSps ISM500, the intake manifold temp runs at or near ambient except when the engine is shut down after a run, when restarted the temp goes up into the 150 range for a few seconds then backs down to ambient or very near it. Stays there during harder pulls So I ASSUME the CAC, tubing, air filter, intake, turbo etc is working good, at the present.
Currently sitting at Xtreme, then MOT.
2 questions regarding the motorhome radiator:
Question 1 - Anyone here have a service contract on their coach?
If so, is the radiator covered under your service contract and if so,
which service contract company are you using.
Question 2 - If you were using solely Distilled water with no additive package in your radiator - what adverse effects could you experience?
Thanks from a newbie.
Robert - Cape Coral, Florida
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Robert, I can not help with question #1, but as to question #2, you do not want to run straight water in the cooling system, while I have no idea about the Distilled water, I do know regular water has too high surface tension and does not cool very well alone. Another way of saying it, regular water is not wet enough. OK, you need some sort of additive (antifreeze is a good one) to make water wetter. Example ever spill water on anything and notice how it piles up, while gasoline will just spread out everywhere as it has a very low/no surface tension ?
The same thing happens in the cooling system just like if you have ever put a pan of water on the stove and heated it, you see all those bubbles around the pan that have air under them, well that is because the water is not wet enough or has too high surface tension. SO, you need some sort of additive to get rid of that condition and make the water wetter so so the liquid makes full contact with the entire metal surfaces to transfer the heat to the radiator.
I am sure there are plenty word smiths, that can describe this much better, I am just an old mechanic.
I would not run straight water, I would run at least 20% antifreeze just to help reduce the surface tension.
Cheers
If you do not run the proper coolant in the cooling system, with your linered engine, you will experience cavitation on the cylinder liners. If this continues, it will erode right through your cylinder walls.
See your Cummins owners manual's section on coolant.
Robert,
I too remember the days of distilled water and perhaps a little linseed oil to keep the rust down. Today, with computer databases and modern chemistry we can see the results of using the wrong coolant and the best ways to avoid problems.
Brett covered the potential liner erosion problem well so I will go up a little higher into the cylinder head.
Pressure caps and a 50/50 mix of antifreeze give more than just protection from freezing and boiling. With an RV, long grades can see maximum power (and heat) for ten minutes or longer. The water temperature you see on the gauge does not give true indication of the many different coolant temperatures seen inside the engine. The highest temperature is usually seen around the exhaust valve area. The coolant on the other side of the cylinder head wall from the exhaust valve may reach very high temperatures for a long period of time and with a bad pressure cap and/or the wrong coolant, the liquid may vaporize in a localized area so there is NO coolant to metal contact to remove the excess heat. This can cause anything from cracks in the head to expansion of the cylinder head beyond designed limits causing leaking or blown head gaskets now or later. The pressure cap and the 50/50 mix, raise the boiling point so this harmful vaporization does not occur until much higher temperatures.
So, use the recommended coolant for your engine, gear down and slow down if necessary to keep temps in the normal range. Lots of posts about keeping rear/side mounted radiators clean.