Engine overheating

[Dick Osterhof]

I have a 2002 Allegro Bus with a Cummins 330 ISC. 78,000 miles on it. I purchased it used. I live in Ridgway, CO and as a result must go over several passes. The engine overheats, even with the outside air temp. at 45 degrees F. in second gear, at 2250 RPM,towing a GEO Tracker. What I have done so far is the caustic wash followed by the acid cleaning of the radiator. Have done a Simple Green cleaning of the radiator from the rear of the MH and the same for the aftercooler from under the bed. The "slobber tube" had been extended sometime before I purchased the MH. I found no traces of oil/dirt on the aftercooler. I am using Final Charge coolant. My next step is to replace the thermostat. The cooling fan looks to be too small and if I can find out what the fan diameter should be, I will measure it and replace it if not correct. Belts are new (I replaced them when I first found the overheating problem). Any suggestions for fixes I may have missed will be much appreciated.
Dick Osterhof (gdo@ouraynet.com)
__________________
Dick & Jan Osterhof

Echo & Peach our Shih Tzus

[Martind4]

Can you see a flashlight through the radiator/CAC? Sometimes it takes more than one Simple Green cleaning to get it clean. With the engine running can you feel the airflow through the radiator? Is the airflow about the same top to bottom and side to side?

When I first got our MH, it took several cleanings to get it the way I wanted it.

[gknott]

The tips of your fan blade should come within 1/2" of the shroud , if they don't maybe someone made them smaller for less noise or some other reason.

[wagonmaster2]

Hi Dick-

Been through Ridgeway many times on our way to Silverton and Durango so know the passes you have to travel.
Last June our 2004 Meridian 330 HP Cat C-7 with 42,000 miles started really running hot over Red Mountain Pass and the two lower ones between Montrose and Gunnison. I tried to clean the radiator at a campground after purchasing a gallon garden sprayer from Wal Mart, which helped a little. When I got back home to Oklahoma I pulled the 2 thermostats, which I understand should be changed every 3 years, and found one of them had come apart and was neither closing completely nor opening completely. Did a real good job cleaning the outer edges of the aftercooler that I undoubtedly wasn't reaching from underneith while I was in the thermostat location and found quite a bit of lint (kind of likes on a clothes dryer filter). After all that the next trip in September to Gunnison, Montrose, Ouray, Silverton, Durango, the temperature set right at 192-194 (I have a Trip Tek to see exact temperatures) no matter where I was driving. I pull a Jeep Wrangler behind the Meridian (used to have a '95 Geo Tracker and loved it but always wanted a Jeep).

A poster recently stated his water pump belt was too loose and caused his heating problem but since you've replaced all your belts that shouldn't be your problem.

Hope you have good luck solving your heating problem, nothing more frustrating than having a vehicle heat up all the time.

Wagonmaster2

[Dick Osterhof]

Thanks for the info. I have replaced the t'stat...it was not opening but about 75% of the way, compared to the new one. Didn't help. Had the radiator and CAC steam cleaned. Didn't help! Hoses are all new. Engine over heats in the flats between Ridgway and Grand Junction at 85 degrees with empty motor home and not towing. Had to run in 5th gear to keep the rpm up and then the temp gage was just below the warning point.
Two things I have noticed about this problem. 1, it does not over heat at the lower elevations on our trips to LA, AL, & SC where we have children and grandchildren. 2. The air flow is high in a circle around the outer sides of the radiator but there is almost none in a rather large circle in the center of the radiator (about 12 to 16" in diameter). The fan blade tips are within a half to 3/4" of the shroud, depending on where I measure.
I am at a loss on this one. I cannot believe the water pump is at fault, but could be. A real tough job to replace!

[Mike Thomas]

I would have a good shop pressure test your charge air cooler. A leak in that system will cause overheating. The turbo charger "stuffs" air in to the engine. Not enough air, and it will overheat. We have semi trucks, and pressure testing the charge air cooler and hoses is a part of every service, it is that important..... Mike

[J Walker]

You surely have done everything obvious. Cleaning the radiator can be accomplished by spraying Simple Green on the inside of the radiator and running the engine to blow it toward the rear. When the fluid comes out clear there is no more dirt and grime. Then just rinse with water. I have done this for ten years and no build up of grime. On the suggestion that the CAC may be leaking you can easily find out by monitoring the turbo boost. You should get close to 30 psi max boost and if not a leak in the CAC or its connections might be the cause. Don't have an engine monitor? Silverleaf has a VMSpc for a reasonable price and it is invaluable.

[Batman_777]

Several threads concerning this same issue have been posted. The result is: When climbing, drive the tach, not the speed. Maintain the tach within the power band for your motor (usually 1600-1900). The motor temp will increase as the load on the motor increases. As the demand increases, you'll notice the temp rising. Try to keep the temp below 220 degrees and preferably, below 215. The fan will kick on once the temp gets up to its pre-set kick-on temp around 210-215 degrees.

If you are in the power band, and the temp is 215 or lower and nothing is broken or plugged, radiator clean.. That's all she can do for the motor and demands placed upon it. You've reached its power capacity.

[Vintage]

Quote:

Originally Posted by Batman_777 Several threads concerning this same issue have been posted. The result is: When climbing, drive the tach, not the speed. Maintain the tach within the power band for your motor (usually 1600-1900). The motor temp will increase as the load on the motor increases. As the demand increases, you'll notice the temp rising. Try to keep the temp below 220 degrees and preferably, below 215. The fan will kick on once the temp gets up to its pre-set kick-on temp around 210-215 degrees. If you are in the power band, and the temp is 215 or lower and nothing is broken or plugged, radiator clean.. That's all she can do for the motor and demands placed upon it. You've reached its power capacity.

Agree X2! You don't have to be the first over the hill. Keep the engine in the power band and go slower.

[Dick Osterhof]

I always drive by the tach and still over heat. The fan is a full time fan so there is no fan kick in. And yes, I expect the temp to rise during a climb but not at 85 on the level while running light and not towing.

[george85643]

I have a 1999 Damon on freightliner chassis with 3126 Cat and rear radiator. Went through the same remedies you have tried without much success. I removed the slats on the rear access door so airflow was not restricted. also sealed the gaps between the radiator and the housing to the rear access so all airflow through the door was through the radiator.
annually I clean the radiator with simple green and a pressure washer. This has solved my problem. I think Damon simply made a mistake by restricting airflow through the radiator.

[Dick Osterhof]

Thanks guys and gals for the many suggestions. I believe the problem has been solved. As you know, I had the radiator/CAC steam cleaned and that did not help. In a nutshell, spent quite some time cleaning the external system, from the back and from the fan side. I wound up using 3 gallons of concentrated cleaner, injected via my pressure washer. From the fan side, I ran the engine at 1500 RPM and sprayed the solution directly into the fan. The concentrate is diluted by the washer. You should have seen the junk that came thru. I went back to my steam clean guys and raised holy hell because of the poor job they did. (I didn't stay to watch...bad move on my part. I know better but had other things to do) I got my money back! Anyhow after several washings the drainage came out clean. After a clean water wash I took the MH up Dallas Divide (CO 62 out of Ridgway) No over heating. YEA! For george85643 I have in the past run with the back access door open to see if that made any difference--none!

[Vintage]

Quote:

Originally Posted by george85643 I have a 1999 Damon on freightliner chassis with 3126 Cat and rear radiator. Went through the same remedies you have tried without much success. I removed the slats on the rear access door so airflow was not restricted. also sealed the gaps between the radiator and the housing to the rear access so all airflow through the door was through the radiator. annually I clean the radiator with simple green and a pressure washer. This has solved my problem. I think Damon simply made a mistake by restricting airflow through the radiator.

The louvers on the rear door only direct the flow and obscure the sight of the radiator. They will not restrict the flow of air from the radiator discharge. The full frontal area of the louvers is the width of the louver times the length times the number of louvers. Added up this is neglegible to restrict the air flow. Or better yet simply take all the removed 'slats' and stack them up sandwitch like and that is the area you say they were blocking.


Dick, Congratulations for taking the bull by the horns and doing your own cleaning job. Now you know it is done right and to your satisfaction and you solved the problem.

[bob109]

Quote:

Originally Posted by Dick Osterhof Thanks guys and gals for the many suggestions. I believe the problem has been solved. As you know, I had the radiator/CAC steam cleaned and that did not help. In a nutshell, spent quite some time cleaning the external system, from the back and from the fan side. I wound up using 3 gallons of concentrated cleaner, injected via my pressure washer. From the fan side, I ran the engine at 1500 RPM and sprayed the solution directly into the fan. The concentrate is diluted by the washer. You should have seen the junk that came thru. I went back to my steam clean guys and raised holy hell because of the poor job they did. (I didn't stay to watch...bad move on my part. I know better but had other things to do) I got my money back! Anyhow after several washings the drainage came out clean. After a clean water wash I took the MH up Dallas Divide (CO 62 out of Ridgway) No over heating. YEA! For george85643 I have in the past run with the back access door open to see if that made any difference--none!

Dick:

Just had the opportunity to use a friends Hotsy Steam Cleaner. I spent almost a hour going over the undercarriage and radiator. If enough time is taken, the hot steam/hot water will remove any and all garbage from the cores. The key is to spend sufficient time and not rush the job. I went over the core from the front/rear sides no less than four times making sure the water vapor/runoff was clear.

Unfortunately, unless you stand over some folks, jobs never get done properly. Glad you at least got a refund. Not sure what you originally paid, but that cost may cover the rental of a Hotsy from a Rental Co. Having access to one for several hours and properly used by the DP owner makes a big differance in the end results

I'm going to do a nighttime inspection of the cores by placing a small lightbulb in the fan shroud and check it on a pitch dark night