Overheating problem - 330 Cummins

Spooky · 02-08-2008, 12:44 PM

My 02 Journey 36DL w/330 Cummins has developed an engine overheating problem. Usually happens on interstate/highway operating speeds on inclines - level highway OK. Unit has had radiator steam cleaned, filters changed, water pump checked and hoses/belts serviced. Towing trailer and all weights verified as within specs. Any suggestions for additional diagnosis or aftermarket product to increase radiator heat transfer ability?

Spooky · 02-08-2008, 12:44 PM

My 02 Journey 36DL w/330 Cummins has developed an engine overheating problem. Usually happens on interstate/highway operating speeds on inclines - level highway OK. Unit has had radiator steam cleaned, filters changed, water pump checked and hoses/belts serviced. Towing trailer and all weights verified as within specs. Any suggestions for additional diagnosis or aftermarket product to increase radiator heat transfer ability?

Harry B · 02-08-2008, 01:41 PM

I don't know how much your trailer weighs, but if it is significant in weight, you would need to keep the RPMs up in the 1900 to 2000 RPM range. I know this is an issue in order to maintain maximum cooling ability on a freightliner chassis.

Did the coach ever not have the cooling problem or is this something new?

Spooky · 02-08-2008, 01:52 PM

Hi Harry B: THANKS for your response. The coach was purchased in 2005 with 25K and it towed a trailer for IRL Races with no OH issues. The trailer I pull is same as other trailer and I had no OH issues until I made the run from Phoenix to Flagstaff in April 07. From then on, the coach wants to run "hot" on inclines. Downshifting to 5th or 4th as necessary to maintain 2K rpm seems to help kep the indicator in the "Normal" range. This seems to be the majority opinion on this site.

Pusherman · 02-08-2008, 02:33 PM

Spooky, a couple suggestions. First, keeping the engine in the 2000 RPM range is optimum for cooling; so downshifting helps here when climbing hills.

Second, I would re-verify that your radiator and charge air cooler are clean. Maybe try shining a flashlight at night from the rear to the front of the radiator. You can access the front side under the bed (sorry, not a simple task) by removing the engine access cover. From the inside (engine side) you can see how well your radiator was cleaned.

Historically overheating problems arise from the slobber tube dripping into the engine side of the radiator and charge air cooler. Sometimes it takes several cleanings, until no more greasy water comes out of the wash cycle, to verify it's clean.

You can try this yourself by using Simple green on a hot radiator; spray both sides with the Simple green, let sit for 10 minutes or so, and then flush with a garden hose, from the rear to the front (engine) side. You may have to repeat this about 3-4 times, depending on how gunked up it is.

The other thing to check is to see if your thermostat is working properly. I did not see this in your original post.

Spooky · 02-08-2008, 03:16 PM

THANKS Don & Mary Ellen: The one thing I need to check on the RO from Beaudry in Tucson is the thermostat. I don't know if they checked it or not. If it was not working, I think that the engine would operate hotter when idling for an extendedperiod - which it does not. I really appreciate everyone's response and all the other info in other posts on this site.

I guess the "bottom line" is there is not a real fix to a bad engineering problem - only good maintenance. I was kind of hoping for a good aftermarket product since nearly everyone with a pusher has experienced a problem with overheating when climbing inclined roads.

Anyway, thanks again.

gunny · 02-08-2008, 03:53 PM

Agree with Don & Mary Ellen. As an alternative to Simple Green, suggest an air conditioning evaporator coil cleaner, Can be had from a place like CC Dickson. Be real carful with that stuff around painted surfaces, it works very well. Read the directions before using. A gallon will cost about $12.00 and will clean at least 4 radiators, right down to the shine.

Pusherman · 02-08-2008, 05:34 PM

Spooky, the only engineering problem I am aware of in the FL CAT engine configurations is that the slobber tube (crankcase vent tube) was not originally extended far enough such that the discharge would collect in the rear radiator. In the newer models the slobber tube is extended below the radiator level.

There are kits that are available to extend the slobber tube. Otherwise, I believe the cooling system is adequate for essentially all situations on the CAT 3126/C7 applications.

zertrider · 02-09-2008, 06:36 AM

P.S. You Have a 330 Caterpillar in your unit, not a Cummins.
Make sure if you are going to pressure wash the rad, to direct the water flow directly straight throught the rad., and not on an angle.

Pusherman · 02-09-2008, 06:55 AM

zertrider's warning is spot-on. In fact it is not recommended to use a pressure washer at all when washing your radiator, as you can damage the fragile fins.

When I was at Camp Freightliner, they recommended only using a garden hose. Wash. Rinse. Repeat.

Spooky · 02-10-2008, 03:49 PM

Hi All: THANKS a GREAT BIG DEAL! You are right, it is a Cat 330 C7. I crwaled under the rig and checked. The engine is painted yellow, just like all Cats - not Red like Cummins. The dealer paperwork was wrong also as it listed the unit as a Cummins. I also checked the radiator from the inside today and found that the fan-side surface is caked with dirt. How come they set up the fan to push air through the rad and not pull it through? Anyway, I've scheduled a rad pull out and comprehensive cleaning. I bet that will make a difference. THANKS again to you all for your thoughts!

ichn2go · 02-11-2008, 02:37 AM

Most folkes don't pull the radiator..Do a search on cleaning the radiator and you'll find lots of info...
I have never did it on my diesel but I have heard its a lot of fun to do, especially if you use rain gear. Good Luck

quikduk · 02-11-2008, 09:14 AM

Just my $.02 but...

I have a Cummins, not a CAT and my radiator and Charge Air Cooler (CAC) are in the rear. The engine fan pushes air first through the CAC and then the radiator. I have a similar issue and after further investigation, this is what I found and what was recommended to correct the issue.

1. NO pressure washer and only "gentle" hose use (my FIL's hoses have about 115 psi!) as you can easily ruin the CAC core and severely damage the radiator.

2. In my case, the units are separated by an "air gap" space of about 3-4 inches...BUT the steel CAC/radiator shroud wraps around completely making it impossible to easily clean each core. This means I will have to do some surgery on the bottom of my shroud but it will ease annual cleanings.

3. My CAC was getting plugged by the crankcase breather tube not being long enough and being aimed at the CAC. I replaced the entire hose with new HD Gates hose and ran it out just in front of the outer right edge of the mud/rock guard. This way, it blows rearwards and to the side while going down the road.

4. The method suggested was that any mild, non-acidic de-greaser could be used, such as Simple Green (non-diluted) etc. Spray it with a "hudson" sprayer (for weeds etc.) and let it sit. You want to completely soak each core from both sides if possible (hence the upcoming shroud surgery). You want to do it when it is warm ouside but on a cold engine and you want the area out of the sun. It helps if you pre-wet the area with the hose. It may take several applications but it will disolve the dirt and grease.

I did the hose through the radiator first only to find out I was plugging the CAC. I then soaked everything and rinsed three times from the inside and outside. For now it is o.k. but I still have several areas to pre-clean. On my model, the fan is a 10 blade job and it is so close between the blades themselves and the blade to the shroud that I cant get to every area from inside the engine compartment. I am determined to get it clean though.

On a side note, this is a perfect time to degrease anything else on your drivetrain that looks yucky (technical term).

Good luck.

Pusherman · 02-11-2008, 05:41 PM

Spooky, as others have already posted, before you pay the $$'s to pull radiators, you should be able to either clean the radiator and charge air cooler yourself, or have someone do it for you, before yanking the radiator and CAC out to have it cleaned.

Both myself and other posters have recommended ways to clean the radiator and CAC in place w/o having to dismantle anything.

If you want the job done professionally, go to your local FL dealer and ask if they will do it for you.

Long term, it sounds like you need to extend the slobber tube to below the radiator level so that in the future the oil from the tube does not collect in the CAC and radiator. Once extended, I would think you could extend your cleaning interval by years.

Let us know how you make out.

Spooky · 02-13-2008, 11:04 AM

Hi All: I can't tell you how much I appreciate all your time and courtesy in posting your suggestions. It seems that throughout all sites, a rear facing radiator/CAC, no matter what engine, is a problem for overheating if not kept very clean and RPM in the 1900-2000 range during incline driving. I have decided to Simple Green with a garden sprayer on both sides (THANKS for the rain suit suggestion) and then rinse several times with a garden hose. We'll see how that works on our trip home to IN from AZ in April. THANKS again.