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Charge Air Cooler hoses
All Series 60 coaches use charge air coolers to cool the air coming from the turbo before it enters the intake manifold.
We have noticed and some members have reported that Prevost is installing flexible hoses in the piping to and from the charge air cooler that appear to be incorrect for the temperatures that occur within the system. In October of 2013 this was brought to Prevost’s attention and the expectation was the error would be taken care of. At this weekend’s seminar it was learned Prevost service centers are still installing hoses rated for 350 degrees on the “hot” side of the system which can have air temps in the 500 degree range. The significantly more expensive high temperature hoses rated for 500 degrees are being called for on the 200 degree “cold” side. The following email was sent to Bill Jensen of Prevost asking for his help in resolving the problem.
But until it is resolved, if you have blue hoses on the system between the turbo and the charge air cooler be especially alert to any signs of an imminent failure. If you are getting the system serviced and new hoses are to be installed you will have to insist on the use of red hoses on the piping between the turbo and the CAC. You can use blue or red hoses on the “cold” side from the CAC to the engine intake manifold. The red hoses are significantly more expensive than the blue hoses.
This is the email sent this morning:
Bill,On October 3, 2013 we had a discussion regarding a Prevost Community member’s coach that had the charge air cooler replaced. At the time the service people in Nashville correctly installed the red (orange) and blue flexible hoses according to the bill of material, which was wrong. The error in the bill of material had the high temperature red hoses to be installed on the “cold” side. The blue low temperature hoses were called for on the “hot side” between the turbo and the CAC. You authorized the folks in Nashville to reverse the hose positions and indicated the needed engineering change would take some time to work through the system.To date it appears the error has not been corrected and based on feedback from some members this weekend blue hoses are still called for on the hot side and and are still being installed there. This was brought up by the members who were affected because in one case a blue hose failed shortly after the CAC was replaced on a 2005 chassis and the owner had the failed hose replaced and it was replaced with another blue one. In another instance a member who knew of our discussions checked his, found it to be in imminent danger of failure, order a new hose to replace it, hoping for the correct red one, and got a blue one instead.I have researched the industry specification for color and temperature limits and determined the blue hoses, regardless of source are rated for a max of 350 degrees. I have measured my turbo air temp prior to the CAC and it has been 500 degrees. The red hoses are rated for 500 degrees. If Prevost were to look at the bill of material, completely disregarding the temperature limits of hoses they would find the hot side blue 2 hoses they now call for are substantially cheaper than the three red cold side hoses begging the question as to why use the more expensive hoses for the 200 degree air on the cold side when the blue hoses being used on the hot side would work for both? The numbers and quantities are transposed and should be corrected.If you are not the proper person to follow up on this can you direct me to the person responsible for changes?Thanks.
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31 Replies
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I am sure it is not for a cost reason as they would pass on the differance to the user. And I am convinced that most of us would rather have th correct hose than to loose it on the road..
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Interesting. My 1999 shell has blue hoses on both sides. Is it possible that’s correct for a pre-egr engine?
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Joelselman,
I just noticed that mine also has blue hoses on both sides…
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Before anyone assumes the blue hoses are inappropriate for the application the only possible way to determine that for certain is to know the max temps the hoses are exposed to.
I know for sure my EGR coach has 500 degree air temps downstream from the turbo because I have monitored the temps via my DDEC reader. One thing to be aware of is the compression of air contributes greatly to the amount of heat the air contains. EGR engines with the multiple position turbo will generate intake air system pressures around 30 PSI under normal conditions, but when the EGR functions the turbo boost reaches almost 50 PSI which causes the intake air temp to get excessive.
If Silverleaf or any engine monitoring system is available on anyone’s coach, and if the intake air temp prior to the CAC can be read it would be appreciated if anyone could post that information. Pre-EGR coaches, especially those with the 12.7 liter might be withing the acceptable operating range of the blue hoses which is 350 degres.
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Mine are blue as well, but I don’t think it’s an issue for the Pre EGR and stacked CAC
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It might depend on the engine / turbo combo. One PC member has a pre-EGR coach and I believe his air temps downstream from the turbo are approaching 500 degrees because it charred the paint on the tubing. He replaced the blue hose and told me it had bonded to the tube, probably by melting onto it. But I agree with Tom in that non-EGR engines that do not require the amount of boost an EGR engine does are likely to be significantly lower temps.
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I purchased my red silicone hoses from Truck Pro and put them in every location when the CAC was replaced,at that time Prevost had the blue hoses specified for the high temperature locations which was the turbo discharge hose,the CAC inlet and the intake inlet.
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Jon,
Not sure if this will help or not. I had my CAC replaced by Prevost Mira Loma back in 2014 and I had read about the hose deal before and worked with Al to make sure I got what I needed. I talked with them before and during the install and was told “the color doesn’t mean anything anymore” Prevost has switched to Volvo parts and they assured me that they are rated for the temps required. So have blue hoses everywhere on the CAC and so far so good..
Thanks for the update.
Bill
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Bill,
I will buy that and completely stop beating this dead horse if you can explain to me why the blue hoses cost half (or less) than that of the red hoses, yet the Prevost bill of materials calls for blue hoses on the hot side and red on the cold side.
If the much cheaper blue hoses are so good for the hot side would it not make sense to use them on the cold side in place of the expensive red hoses? That would save owners around $300.
At the seminar this past weekend a member that had a recent CAC replacement ended up with a failed blue hose on the hot side and had to have it replaced and he got another blue one which Prevost insisted was the correct one. If it was why did it fail so soon after the CAC replacement?
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Here’s what I’ve discovered about Turbo outlet temperatures
verses boost pressure on my engine. If I’m using a combination of settings that
produce over 40 lbs of boost I’ll see 500 degrees or slightly more on the TCO
temps and approximately 400 degrees with settings that produce mid to high 30’s of
boost pressure. I don’t remeber running a tune that produced low 30’s but I would
expect the TCO temps to be low to mid 300’s at that boost pressure. If you
have a pre-EGR engine it should be producing about 32 lbs of boost so (blue) lower
temperature hoses are OK on the hot side(TCO). Since an EGR engine produces
over 40 lbs of boost you need the higher temperature hoses (red) on the hot
side (TCO). I don’t buy the story about hose color doesn’t matter, it could be
true, I’d want to do more research before I felt good about installing blue hoses
on the turbo outlet side with an EGR engine..Ken
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Blue hose removed during CAC replacement on 2005 Marathon 50K miles. This hose came from the hot side and was an original .
This should give members some idea why this entire conversation is about replacement using correct type hose on the hot side. This hose would have failed at some point. When you blow a turbo hose you are done, finished, parked along side of road.
Heat is the enemy , Jon is correct and went to bat for me when I proudly sent him a picture of the finished job at Prevost.
That’s when all hell broke loose at Prevost Nashville Oct 3, 2013.
We held our ground with the known fact that temp readings are over the allowable max for blue hoses. The rest of the story is Prevost stocks the red right along side of blue. 4 hours later red hoses were re- installed on the hot side.
I remember the policy would be changed… but 2 years later still the same blue hoses go on the hot side.
Sidebar….This represents how Jon and Tom go above and beyond with members on this site. Compared to others….. Both have a keen understanding of how these buses work and support members with accurate information.
Thanks guys…you made the right choice starting your own site when others places now have trouble keeping something on the screen and actually still collect money for absolutely nothing.
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And a big THANK YOU to Al for my CAC change and the proper hoses installed!
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On my engine all hoses on both side hot and cold are red hoses.
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Bill Jensen of Prevost and I have been communicating on this issue.
It would be a very big help if anyone that has had a blue hose failure, or a work order regarding a CAC replacement in which the blue hoses were put on the hot side. I will need the VIN of your coach, but if possible a work order number or the date of the work along with what facility did the work.
Bill has been very helpful and supportive to conversion owners and is going to follow through on this if we can provide him with details so he can evaluate this issue and needed action.
Send me the information via email please. We don’t want to make this into a witch hunt, but do want to make sure if there is a problem as we suspect it gets resolved.
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Hey guys……….I need data on coaches that had the CAC replaced, the VIN, where it was done, and if possible the work order number. Prevost needs this information to evaluate the problem and get it resolved, otherwise nothing is going to change.
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