Overheating Diesel Pusher

[Terryk1312]

We recently bought a 2004 Winnebago Journey (39 ft). Overall, it's in great shape. It is on a Freightliner chassis, has a 6 speed Allison transmission and a Catipillar 330 hp diesel engine.
PROBLEM: Engine overheats occasionally, usually when climbing a long grade in hot weather. The radiator was supposedly flushed before I bought it. It looks clean ftom the outside /rear. I pressure washed it with soapy water from the rear / outside. I've managed to reduce the rate it overheats by;
a. Slowing down.
b. Shifting manually to force higher rpms (1500 min. and 1800 preferred ).
c. Using the ONAN QUIET DIESEL to run the coach AC and not running the dashboard AC.

On this site, I've read about cleaning the intercoller. Where is it? Is it right in front of the radiator? Is the rectangular steel box with lower radiator and water pump, as well as turbo air (I think) lines going to it, the intercooler? Do I need to remove the manhole cover under the rear clothes closet floor to get to the inside of the radiator (for cleaning and inspection)?

Has anyone used supplemental, electric fans on the rear outside of the radiator?

Has any one tried water spray between the fan and the radiator?

[Ray,IN]

There are several threads explaining how to clean the radiator "sandwich" to solve the overheating issue. I now forget whether they are in one of the MH specific forums or the Freightliner forum.
There are many threads about overheating, hopefully one of them fits your exact chassis and engine: http://www.irv2.com/forums/search.php?searchid=12665328

[MtnTrek]

Hi,
As Ray noted, I'm not versed on your particular coach. In general though.


Research your radiator's configuration to see if they are stacked or sandwiched.
Be cautious "pressure washing" any finned coils as bent fins can be di$a$trou$.
Inspect the coils from the engine side as there could be grime that is not cleanable through the outer side. Check for drizzle from blow-by slobber tube etc.


I helped one fellow with an overheating tow vehicle. He'd flushed the water side, and sprayed out his A/C condenser well (sandwiched in front of radiator). We removed the grill fascia and fan cowling only to flush out (from engine side) a mound of silt and debris particularly near the sides near the tanks. We added some distilled H2O, he'd estimated his mixture wrong. It never overheated again.


I used to maintain some DOD equip. that simply wouldn't stay on-line with a 50/50 glycol mix in the summer heat.


Insure you coolant mixture is correct. Use a specific gravity tester. Water is a far better conductor and mover of heat than ethylene glycol. The optimal mixture ratio would be only for the maximum temp to increase boiling point and minimum temp to avoid freezing and prevent corrosion. Any increase over 40%-50% decreases heat removal efficiency.


Sounds like your trying other methods like downshifting and slowing down, removing some other heat loads.
Some manuals prefer closer to 2k RPM for long steep grades.
Yes the intercooler is piped in-between the turbo and head. Naturally your air filter is clean.


Aux. fans sound expensive. Our local Metro Hybrid buses use some monstrous cooling fans. Although they're mounted inside the compartment they sound like afterburners... LOL


I wouldn't recommend the water misting thing, doesn't seem practical to have that much distilled water around. I once attended a church where some retired engineer in the congregation thought he'd save them some cooling moneys. He set some sprinklers near the condensing units. What a mess, through evaporation, sure there are latent BTU's short term, but the residual calcium carbonate left on the fin$ wa$ like in$ulation. Water & associated sewer charges, well enough said.


Best of luck.

[Mr_D]

On the '02 DSDP I had to remove a lower plate and found that there were a bunch of pine needles between the CAC and radiator. Once that was cleaned out the cooling worked fine again.

[Scatterbrain]

Is this side or rear radiator? Is the fan functioning properly?

[dc8cappie]

Check out these links. First link has good pic's.

https://www.google.com/?gws_rd=ssl#q...e:www.irv2.com

[OLYLEN]

Best cooling RPM for the Cat is 2200, you are running in the highest torque area and are prone to over temps at these RPM. Also check as above where the slober tube does its thing on the radiator, lower right side. There are several threads on cleaning, how and what to use. You can also extend the slober tube beyond the radiation but then the towed suffers or put a capture device on the slober tube.

LEN

[cowrv39]

Have you checked the thermostat?

[Oldone1]

Had same with 350 cat. Change thermostats, recommend once a year by cat, make sure to extend slobber tube, and pressure wash the heck out of the radiator.

[Roger G]

Had a friend with a similar problem with a Revolution. After changing water pump, thermostat, and everything else plus having the radiator flushed and cleaned on the outside he finally consented to a new radiator. After removing the old radiator and sitting it on a pair of sawhorses, pink slim started running out of the input and output tubes. It seems that sometimes during a service, a tech had topped the radiator with a non compatible anti freeze and the two coolants had reacted to form a thick slime. The slime was too thick and would not flush out with water and restricted the flow that caused the engine to overheat under load or very warm weather. He had the old radiator chemically cleaned at a radiator shop and voila, cool engine. It was a 2005 model if that means anything.

[Mr_D]

Originally Posted by OLYLEN

Best cooling RPM for the Cat is 2200, you are running in the highest torque area and are prone to over temps at these RPM. Also check as above where the slober tube does its thing on the radiator, lower right side. There are several threads on cleaning, how and what to use. You can also extend the slober tube beyond the radiation but then the towed suffers or put a capture device on the slober tube.

LEN

2200 is the max HP rpm, max torque is 1440 according to the charts I just looked up. Running just over torque peak gives best mpg, running around 2000 is best for cooling.

[dnystrom]

Clean that radiator .Steam will be the best method but you can pressure wash it with being very careful not to bend any fins. Use a solvent first to loosen that crud. Then check the thermostat. The is a part of regular care with the cooling system as it's a rear radiator and sucks every thing in it.

[Dutch Star Don]

Terry.....my sister had the sister coach to yours, a 2004 Itasca Meridian with a 350 Cat. First off, the charge air cooler (CAC) and radiator are sandwiched, one right in front of the other. You need to lift your bed and remove the large metal cover under the bed.

You'll see the two units sandwiched together. Here is the problem, they're only about 2" apart. If you take a flashlight and look between the two, I'll guarantee you'll see what looks like hair growing between them.

Get some Dawn dish soap and a garden prayer. Take the sprayer and keep spraying until you can soak everything between the two, it will take some work. We took a pvc pipe, similar to one of the toilet rinsers they sell at RV stores, connected it to the hot water heater at the house and stuck it between the two units and just kept rinsing.

You may need to soak everything a couple of times to get it clean. Unless you have other issues, this will solve your heating problem.

Lastly, your coach had an issue with the "slobber tube", a tube that lets engine blow by escape out of the engine. When these coaches were new, they let this tube hang down on the passenger side by the engine and the blow by, which is oily smoke from the engine, would get sucked into the radiator and CAC. Most people extended the hose after a year of ownership, so that it was past the radiator and CAC, but you need to check to see if yours has been extended.

[rver98]

Originally Posted by Dutch Star Don

Terry.....my sister had the sister coach to yours, a 2004 Itasca Meridian with a 350 Cat. First off, the charge air cooler (CAC) and radiator are sandwiched, one right in front of the other. You need to lift your bed and remove the large metal cover under the bed.

You'll see the two units sandwiched together. Here is the problem, they're only about 2" apart. If you take a flashlight and look between the two, I'll guarantee you'll see what looks like hair growing between them.

Get some Dawn dish soap and a garden prayer. Take the sprayer and keep spraying until you can soak everything between the two, it will take some work. We took a pvc pipe, similar to one of the toilet rinsers they sell at RV stores, connected it to the hot water heater at the house and stuck it between the two units and just kept rinsing.

You may need to soak everything a couple of times to get it clean. Unless you have other issues, this will solve your heating problem.

Lastly, your coach had an issue with the "slobber tube", a tube that lets engine blow by escape out of the engine. When these coaches were new, they let this tube hang down on the passenger side by the engine and the blow by, which is oily smoke from the engine, would get sucked into the radiator and CAC. Most people extended the hose after a year of ownership, so that it was past the radiator and CAC, but you need to check to see if yours has been extended.

All good advise by Don. This is my method and changing your coolant AND thermostats. They tend to be a problem also.

Good luck