Charge Air Cooler replacement information needed

[Birddog Pilot]

Last year it was the coolant radiator and now it’s the charge air cooler. We’re five weeks into a five month trip and if this any sign of progress, or the lack of, things are not looking too good. We are here at Cummins Northwest, Corburg, OR having a suspension air leak repaired and out of curiosity I decided I wanted them do a CAC leak-down test. Apparently, a leak-down of 7 pounds in 15 minutes, or something like that, is a Cummins’ or industry standard; we’re right at the seven-eight pound point. Our extended warranty people are involved, so there’s no turning back at this point; even though the Cummins people say everything should be fine if we decided to press on with the trip. I really don’t want to take that option, both for the warranty requirements and also the possibility of creating other engine, manifold, or turbo problems.
Mike, the service writer, is a little vague about whether or not they’ve done any Alpines; and seems not to have the information regarding CAC manufacturers or part numbers that would apply to our coach. In fact, he just said he can’t even give an estimate to the warranty people until the CAC is removed. The situation is not sounding too good at this point. I know that Cummins NW has received very good reviews for service from many of our Forum members, but after reading ”Service Beware” by Kathy Nicholsen today it makes me a little nervous about settling-in on a major repair with these folks. As I mentioned our hands are pretty much tied with the extended warranty people being aware of the CAC situation, and their requirement to not proceed with a “known problem.”
I’ve read some good reports here on the Forum regarding the Dura-Lite CAC from Canada, does anyone have any pertinent information on their cooler, or those of other manufacturers? Any part numbers might also help to get Cummins headed down the right path before they start tearing things apart.

[bigfish]

Dick,
You can try Onan Indiana (574-262-4611), they replaced mine in Nov of 2008. They ordered and installed it. Additionally, they have or at least had an Alpine as a company coach so they are familiar with issues surrounding the CAC & radiator leaks. They are a Cummings Coach Care facility. They should be able to advise Cummings Northwest of CAC mfg & p/n. You may not notice any performce issues with your leaker unless doing some mountain driving where it could cost some speed on uphill climbs.
BTF

[Renipladlo]

Not to degrade the CAC issue, but we had the high side of the CAC/Turbo Output hose blow on our way home. WRV used the incorrect type of material for this hose connection. Ours was the wrong temperature rating. See if the leak is coming from this hose. If you are looking at the engine, it is on the left side - to the left of the expansion tank (radiator) and down some. Feel around the hose and see if it’s bulging any (front side of the hose). Ours was making a loud hissing noise, which sounded like a large air leak. It took me about 40 minutes to change this hose. The cost was $130.00 plus shipping.

You can get Cummins to order it from Purosil Company (see - Purosil Silicone Hose) the P/N: 3648-400-MK (Phone: 800-877-5342) and it's made from Armid. It's a 90 degree elbow shaped hose.

Cheaper than a new CAC, hope I don't have to go there.

Macs Radiator in Portland was rumored to also be able to make up the CAC if I remember correctly, but I could be wrong.

Hope you are out of there and on the road soon.

EM can correct me on this, but I don’t believe you can pressure test the CAC without taking off the air connections and plugging one end, and put a fitting on the other side with a pressure gauge. It should hold air and not lose it, or only lose it to the specifications mentioned above.

To be safe, I would ask for written documentation for the testing, and recommended solutions. Ask the service writer to make sure he inputs all the testing documentation into the service database at Cummins based on your engine serial number. Any Cummins distributor/shop/coach care facility then can access this documentation so if you decide to keep going down the road, the next Cummins shop can just look up your engine serial number and read all about this issue. Make sure they enter any specific test data into the record as well.

This is to cover them as well as you, so if the problem gets worse, you will have it recorded in the database. Also get it printed out and keep it with your maintenance records.

I have had excellent service at the Corburg Shop as well as the Portland, OR facility on Swan Island. If Coburg does not feel confident doing the repair, and you are sure it's necessary, the shop in Portland has around 20 bays and they work on all kinds of large trucks, and may be better equipped to handle the repair, as Coburg mostly works on RV's. But, call them first, and get a price quote, as it sounds like lately, each shop has different labor rates, and all believe RV'ers are made of money. The Coburg, OR facility also work on large trucks, but mostly RV's, since Country Coach, and Monaco are located close to this place.


I have not heard good things about the Centralia, WA facility based on one alpine owners report. I have not used them based on that report.

[Birddog Pilot]

My thanks to both BIGFISH and Monty for your response and information. I was in error when I said that the Cummins' "Leak-down Test" was run for 15 minutes, it is only 15 seconds. I verified Cummins NW's information with a tech at Cummins headquarters and yes, the elbows are removed, the CAC is capped, then the unit is pressurized to 30 psi and timed for a leak-down not to exceed 7 psi in 15 seconds. After a re-consultation with the service writer here at Cummins NW he revised his earlier statement and pronounced that my CAC leak-down was in the 6-7 pounds range. Even though this is near the maximum allowable, it is never the less within allowable limits. I was further assured by Cummins NW and Cummins National that even with an increase in leakage I would see only a decrease in performance and no harm could be done to turbo or intake manifold. To be on the safe side I asked that checks be made to the turbo, intake and exhaust manifolds; all were in excellent condition.

With that information we have decided to press on with the journey, keep on the lookout for any decrease in performance, and have the CAC retested when we get back to San Diego this fall by my local Cummins Cal Pacific facility. I know that they have current experience with the Alpine CAC testing and installation. Incidentally, they will only recommend and install the Canadian built Dura-Lite CAC.

Monty, when I had the coolant radiator changed about 10 months ago, the CAC was supposed to have been pressure checked by R.V. Specialists here in San Diego. At that time I did have them replace both CAC elbows, hopefully they used the correct elbows. Having new CAC elbows, of any type, is probably the good news. The not-so-good is that I rather doubt, considering the work done on the radiator installation, that the CAC check was ever performed. If it was done, I also would be surprised if they even knew what the offical leak-down procedures entailed or the pressure limit range. But, that's another story, the "R.V. Specialists Saga," that I'll leave for another place and time. Suffice to say, I definitely would never recommend anyone seeking any maintenance to go this facility.

Once again, thank you both for your input; your information is excellent.

[Renipladlo]

Birdog Pilot, you are welcome. I hope based on your comments that they did change the elbows. Regardless, the one which gave us the trouble was the output side of the turbo, and so we would not have "sucked anything" into the system. It was more painful to purchase the new hose than it was to put it on. I have added diesel machanic to my resume'.

If you have more information on the Dura-lite CAC, please post it here, as I keep various notes on my PC about needed parts from speciality houses. I hope I never need to replace mine, but who knows. I am diligent about warming and cooldown of the engine, so I hope I don't stress out those parts by doing that.

Safe travels, and if you ever get to Vancouver, WA give us a shout.

[Birddog Pilot]

Hi Monty,
If you mean, did Cummins NW change the elbows after doing the CAC leak-down, no they didn't. I figured as long as these were changed about nine months ago they are probably still "good to go." When we get home this fall and I have our local Cummins Cal Pacific do another CAC check I'll make sure that all the correct and appropriate temperature elbows go back on at that time.

By the way, I've been enjoying your excellent comments on the windshields leaking. We've had rain off and on, mostly on, for the last five weeks as we work our way slowly up towards Canada. We too have had a couple of heavy rain days that produced very slight interior windshield water run-down while driving in heavy rain, and absolutely no intrusion during static conditions. I did find that there were large voids in the front outboard running light RTV sealing. I cleaned the areas and hit them with more clear RTV; so we'll see what happens during the next rain event. Also, about eight months ago I completely cleaned both the glass and surrounding fiberglass cap area of all old black window sealant and did a re-seal; that seems to be holding up fairly well.

Yes, if I do go the Dura-Lite replacement next fall I'll drop you a PM on the specifics.

[Renipladlo]

Thank you BDP. You mentioned another shop changed the elbows. But no big deal, as it seems you are going to stay on top of this one to make sure you don't loose air pressure. If you have silverleaf monitoring, just make the boost pressure one of the 6 different action items the system can show, and if it starts to go down (I think) then you might have a leak.

You would it seems hear a loud air pressure leak, but don't remember hearing anyone mention that but me when we lost the elbow. That noise sounded like we had the leak in the front of the coach as it was just echowing toward the front. It was very loud, you cannot miss that noise.

[EngineerMike]

You'll hear the blown elbow, but probably not a sub-par CAC. You can probably read the lost boost, but only at some point. W/the variable vane turbo there is boost commanded and boost acheived, and my guess is that boost achieved is rev'ed up till it equals commanded, till some limit state is reached, beyond which the system can't keep up and boost is actually lost. At that point you will have diminished performance, measurably lower fuel economy, and possibility of noticing on the boost reading.

[Renipladlo]

Thank you Mike for explaining this to all the assembled owners. I was not aware we have a variable turbo, I thought those vanes were fixed, or maybe they are and the ECM commands a higher RPM for the turbo, so the boost is achieved.

Regardless, it's magic until the CAC or an elbow fails, then it's repair time. I suppose I would have the technical ability to remove the CAC and radiator, take them someplace and have them repiared, or contact a shop and have them rebuild it/build a new one. I also assume I could put the thing back in, and hook up everything and make it work. I would also assume it would take a month or longer for everything to come together and be available for reassembly. I hope I don't have to ever go to this place and go through it.

[Birddog Pilot]

Again, thanks to one and all for the information. Coming over the Cascades this morning from Coburg to Bend on HWY 20, I decided to get some max performance boost readings. We're towing of course, and at the the 4000-5000' level, 6% grade, 4th gear, max throttle, floor-boarded, I forget what the tach was showing, about 45-50 mph; I was seeing 29.6" to 30.2" of boost. I would imagine at sea level it would probably equate to about 32". So, I guess the question is with a CAC leaking 6-7 psi, right at the limit, is that performance all that bad? I really don't think so, but of course I don't have anyone else's performance to compare with. Any pearls of wisdom would be appreciated.

[Renipladlo]

I was getting similiar numbers coming across the mountains of eastern oregon, so I think you are in the ball park. Mike mentioned bad economy, so what is your average fuel milage. Now with that siad, since we have the Hydro Hot, that takes a small amount of fuel, and so that throws off my numbers, but I'm getting someplace between 7.9-9.0 depending on the terrain and how fast I'm going. For sake of numbers we tow a 2009 Jeep Wrangler Sahara which comes in around 4400 lbs. If I am not towing, I also average 180-185 operating temp, towing those number go up 10 degrees.

[Renipladlo]

BDP where do you guys live? We are in Vancouver, WA. If you are close to us when home, we should hook up for some coffee.

[Wayne R]

Wow mt CAC must be missing in action. I have averaged 7.0 MPG for 48,000 miles. I occasionally see high 8s but that soon changes. I always seem to be driving into the wind. My boost reads a high of 31.8.

My CAC was changed when my radiator was replaced at 24,000. The WRV mechanics just swapped the radiator and CAC together the CAC was fine. I have not noticed a change in performance and or mileage.

[Old Scout]

I dont have a lot of data points to offer here but our 2003, over the last several years, had gone from avging in the mid to high 8's to mid to low 7's mpgs. Everything else being equal, which it never is, I chalked it up to ULSD fuel and or phases of the moon.

Last Dec, I finally complained to my local Cummins guys about lower mpgs and "felt" the engine was a bit sluggish [no Silver Leaf to verify boost]. They didnt perform a leak-down check but did discover a "minor" CAC leak.

Upon returning from DRR-IX, I [DIY] removed the CAC and had it cleaned/resealed by a local truck radiator/CAC repair shop [Cost was $85--they reused the old gaskets (maybe not a good decision but we will see)]. A subsequent trip to WI, FL and back to TX, we avged mid to high 8's and an occasional low 9's mpg. Cant say that the "feel" of the engine has changed but mpg has improved.