Community Forums

Larry Q · 07-11-2010, 11:46 PM

We are stuck in Bullhead City with a over heating problem. I need to know what motor I have in My 1999 Monaco Diplomat. All that I know is it has a 275 HP with a Banks Kit. Can anybody help? Thanks Larry

RustyJC · 07-12-2010, 04:21 AM

Probably a 24 valve, Bosch VP-44 injected B-series (5.9L) ISB. If so, the thermostats in these engines have been known to go bad with some regularity, so you might start there. Also check the radiator for plugging from the oil breather tube.

Rusty

Larry Q · 07-12-2010, 08:36 AM

Thanks so much Rusty!

mickey53usa · 07-12-2010, 11:50 AM

On my 99 with the 275, after getting to my destination, I would let the engine cool about 30 minutes and then spray water through the radiator. It helped keep the dust out and if it was warm would help flush any oil residue away. It only overheated one time in four years, and that was because I neglected to do the water rinse for a few trips.

J Walker · 07-13-2010, 09:04 AM

Another possibility is that you have a big build up of oil and dirt on your radiator which must be a rear radiator. If the valve breather is not low enough you could be getting oil on your radiator and of course dirt will stick to it. You can spray the radiator with a Simple Green solution, let it sit a while, and spray with water. Repeat the process and when the water comes out clear it is clean. A dirty radiator can cause your problem.

Raca-roni · 07-13-2010, 06:14 PM

J Walker,
I have a friend that had a 1999 Diplomat with a 275hp 5.9 ISB Cummins. A rear radiator setup. He had a similar overheating problem and we did the Simple Green and water flush to the radiator. Boy you should have seen what hit the ground from that radiator.......What a mess of sludge and dirt......

Hooligan · 07-13-2010, 08:04 PM

Larry: the problem discussed by J Walker is very common with the rear radiator, cleaning is more effective if the simple green and rinse is applied to both sides of the radiator/ Charge Air Cooler sandwich. One caution is to avoid a pressure washer as it will probably bend the radiator fins...
Recommended as part of your annual maintenance. The Simple Green is a good de-greaser but also unlikely to damage the radiator.
Search here for "slobber tube" for more info.

Dutch Star Don · 07-13-2010, 08:23 PM

Rusty.....Here is the brochure for your coach from the product archives The Monaco Diplomat Motorcoach

hardyk · 08-17-2010, 11:10 PM

I have a isb 260 HP cummings in a spartan chassis, and am new to Diesel pushers. I have a overheating problem on moderate grades in high temperatures. Is this normal? I have tried compressed air cleaning of the radiator, but not much effect.

justlou · 08-18-2010, 08:51 AM

More information would be helpful. What size coach, weight, what are you towing, ect?

Hooligan · 08-18-2010, 07:49 PM

HardyK: With a rear radiator- Older Cummins ISB engines have a Crankcase breather tube (Slobber tube). The oil mist from this breather was drawn by the fan into the Charge Air Cooler and radiator. This black greasy film collects dust and dirt that blocks the airflow. Compressed air will not move it, but Simple Green or a good degreaser will cut it loose to be rinsed out. Be sure the cleaner is safe for your radiator, (most are aluminum), and I have the best results cleaning and rinsing from both sides of the radiator.

Hope this helps...