Community Forums

skyguy62 · 06-05-2008, 05:33 AM

Dare I say "hvy-jet" returns to the road;for how long is anyone's guess. The replacement of the Charge air cooler (for a full timer may require expensive living alternatives)took from 6 Nov to 30 May.

When it came down to the wire "Radiator Specialists" agreed to manufacture a replacement and sell direct to me (price $1542). Coach care (Cummins Cal Pacific) in El Cahon, CA was very supportive thru ordeal; WRV ... useless! The new unit on arrival FAILED a pressure test and had to be returned to "Radiator..." for rework. Coach care said their experience has been that 20% of CAC's fail that is why they test units before installing.

Point of posting: The old unit is headed to "Duralite" of Canada to see if a replacement can be re engineered and made availible in the near future. This will be helpfull for us full timers that cannot spend the 8 week turnaround time out of our coaches when "Goodsam CSP" provides 1 day housing for each 8hrs of labor (3 days max). Last challenge is having to wait to see how much coverage CSP will reimburse.

When a price and date for unit is avail I will contact "Enginner Mike" I have heard their warranty may be as long as 10 years??!

skyguy62 · 06-05-2008, 05:33 AM

Dare I say "hvy-jet" returns to the road;for how long is anyone's guess. The replacement of the Charge air cooler (for a full timer may require expensive living alternatives)took from 6 Nov to 30 May.

When it came down to the wire "Radiator Specialists" agreed to manufacture a replacement and sell direct to me (price $1542). Coach care (Cummins Cal Pacific) in El Cahon, CA was very supportive thru ordeal; WRV ... useless! The new unit on arrival FAILED a pressure test and had to be returned to "Radiator..." for rework. Coach care said their experience has been that 20% of CAC's fail that is why they test units before installing.

Point of posting: The old unit is headed to "Duralite" of Canada to see if a replacement can be re engineered and made availible in the near future. This will be helpfull for us full timers that cannot spend the 8 week turnaround time out of our coaches when "Goodsam CSP" provides 1 day housing for each 8hrs of labor (3 days max). Last challenge is having to wait to see how much coverage CSP will reimburse.

When a price and date for unit is avail I will contact "Enginner Mike" I have heard their warranty may be as long as 10 years??!

Fly'n Paws · 06-07-2008, 07:03 PM

Wow, wasn't happy to read your post today. Here we sit in SLC, UT and were told we have a leak in the CAC. Radiator Specialties was very informative until they realized that they put in a new Radiator and possibly a CAC just under a year ago and then they put us off until next week until they "could investigate it further". Cummins says the unit is still drivable but hugely underpowered and we need to be extremely careful with long climbs. Hard to avoid returning home to Colorado. We have an appointment with Radiator repair facility Monday to see if they think it can be repaired, if not.......!!! We aren't full timers, we were just heading out for a week long vacation, and hate to leave the RV in UT for repairs while we return to Colorado. Wish Duralite was superspeed in building a replacement. Would be curious to see if CSP helps you out.

Renipladlo · 06-08-2008, 07:50 PM

Ok, don't have a clue what the Charge air Cooler is? Please explain in much detail on this forum. How long owner of the coach, how many miles, lots of details please. Is further cushioning possible to keep this from happening? Cummings ISL manual in Maintenance Schedule says this is a 3 month check item, does not say where or how to do it. Please inform new owner of APEX Mid Door please.

RoadRohrers · 06-09-2008, 01:58 AM

Per Wikipedia:

Charge Air Cooler: charge air cooler (also known as an intercooler) is used to cool engine air after it has passed through a turbocharger, but before it enters the engine. The idea is to return the air to a lower temperature, for the optimum power from the combustion process within the engine.

That's the basic. Sure there is more complication, but that is what the CAC does.

EngineerMike · 06-09-2008, 08:01 AM

Old- the intercooler or CAC is the radiator-looking thing in the sandwich of radiators that has the 3" tubes in and out. The turbo charger compresses air to fill the cylinders with greater-than atmospheric pressure (allowing higher diesel fueling and therefore higher horsepower from the same size engine), but drives up the intake air temp in the process. Without an intercooler, the in-cylinder pre-combustion temperature would be higher by 150 to 250 degrees, which when added to the combustion temperature rise would make proper engine cooling difficult.

If there is an air leak from the CAC, you are not getting proper boost to the engine, and horsepower will be less than desired. Fuel mileage may also suffer and emissions may exceed standards.

skyguy62 · 06-09-2008, 08:46 AM

I am not a mechanic so I am only repeating what I was told by "Coach Care Cummins Cal-Pacific": The air comes into the CAC at approx 300 degrees and goes to the engine at 100 to 150. The thermal stress across the radiator is quite high and many of the units are not to it. They added that as many as 1 in 5 fail but it is hard to detect. Best bet is if you are slow accelerating from a light or stop sign after the engine heats up (1/2 hr driving)or mileage is poor, you might think of having a radiator shop do a pressure test.

With the pressure pumped to 15psi and the engine not on you can feel air leaking by running your fingers along (top to bottom) of the end cap (rear of coach). WRV had orginally directed to tighten all the bolts to reset the internal gasket (no effect but worth a try). You can hear the air escaping, when the engine is running there is no way of knowing about the leak till: milege falls off, hesitation in acceleration, cracked exhaust manifold (Cummins said this is the biggy that leads to discovery), and when the engine radiator springs a leak most shops (while in there working) reccomend pressure testing the CAC.

I complained of performance problems at the one year point at a factory (major repair session); WRV said my engine software was not properly programed (? whose fault?)and that as I drove more the engine would be more efficient (I had 12,000+- miles). This past year of travel I averaged 6 and 1/2 mpg and several near misses at intersections so went to Cummins. They said due to the sandwich construction (Transmission cooler,CAC,Radiator) and the installation by WRV that no other bench ready unit fits. Also they felt that the light weight aluminum unit was not up to the load on it.

We will leave on a 5080 mile trip on the 20th of Jun and hope to see better mpg and performance. When I hear from Duralite I will post; it will be great having a hvy duty unit availible from stock and not have to wait for a custom build.

EngineerMike · 06-09-2008, 10:22 AM

The engines came assembled to a point from Cummins, and include the ECU and other Cummins proprietary parts. WRV had (till the auction, has) the same software I do which will allow setting various engine parameters like tire diameter, and reading the entire engine sensor array, but not reprogramming fuel/air tables. So to the extent engine programming was an issue, that woulda been a Cummins problem. FWIW, I'm guessing you'll be happier w/your new mileage by 20% or so.

Renipladlo · 06-09-2008, 01:03 PM

Intercooler, knew it by that name, Ford truck had one, never had issues with it. Cummings just had unit, guess, next oil change, they will need to check it, and hopefully by that time, we will all have a place to get a new one, of better quality.

Fly'n Paws · 06-09-2008, 07:18 PM

When you hear from Duralite I'd sure like to have the information. We have a temporary fix to our problem with a 2 part epoxy that is heat tolerant, the fix seems to be working fine and we should be able to make it back to Colorado but replacing the CAC is still the next step. Feel free to email me privately at flynpaws@qwestoffice.net if you're able to get duralite information.