Community Forums

StuartT · 06-09-2021, 04:39 PM

A number of DP members, including myself, have been plagued by overheating on the side radiated ISL 400 engines. We use every trick in the book to try and avoid that overheating warning buzzer, which usually starts blaring around 230 degrees. We are usually in hot weather or high altitudes or both, and we shift down, turn off the ac, call for max cabin heat, let off some of the throttle, and when all else fails we pull over, let the engine cool down, then have the DW drive the dingy the rest of the way up the hill to lighten the load.
I tried all the remedies; complete engine flush, new thermostat, installing a wax valve controller, doing multiple Simple Green radiator fin cleanings, checking fan blade rpms, checking the water pump for coolant flow, replacing radiator cap and pressure testing the cooling system. Nothing helped, so I finally broke down and took the coach into a RV repair center to have the CAC and radiator completely removed, separated and cleaned out.
Last week we left Apache Junction for Show Low where we will be spending our summers evading the suffocating heat of the greater Phoenix valley. Hwy 60 has several long hills, most notable being the long decent into and back out of the Salt River Canyon. It was 95 degrees when we started into the canyon, and we were pulling a Jeep Wrangler 4 dr Unlimited. Crossing the river and starting up the other side my stomach was in a knot. This is exactly the scenario where we would have been in deep kimchi before, overheating almost immediately. But nothing happened. The gauge rose to the upper portion of the normal range, the engine diagnostics indicated a temp of 218 degrees, and I was all smiles.
So, if you are plagued like I was, frequently overheating and unable to resolve it, get that radiator and CAC out of your coach, separated and cleaned out.
Take a look at these pictures of the two components and you will see why Simple Green or other cleaner efforts are generally ineffective against plugged radiator fins.

Flyer15015 · 06-09-2021, 04:57 PM

Mine's not a DP, but I added a section of black nylon screen over the AC condenser, AND wired my 2 pancake fans on a toggle switch.
Now I can pull Monarch pass with ease, and not worry about a "boil over'.

Mike in Colorado

shootist · 06-09-2021, 09:35 PM

Yep, I have good night vision. Only way I can get through the desert in the summer is at night. I won't let mine go over 205.

CaptV1VR · 06-10-2021, 12:41 PM

Quote:

Originally Posted by StuartT

A number of DP members, including myself, have been plagued by overheating on the side radiated ISL 400 engines. We use every trick in the book to try and avoid that overheating warning buzzer, which usually starts blaring around 230 degrees. We are usually in hot weather or high altitudes or both, and we shift down, turn off the ac, call for max cabin heat, let off some of the throttle, and when all else fails we pull over, let the engine cool down, then have the DW drive the dingy the rest of the way up the hill to lighten the load.
I tried all the remedies; complete engine flush, new thermostat, installing a wax valve controller, doing multiple Simple Green radiator fin cleanings, checking fan blade rpms, checking the water pump for coolant flow, replacing radiator cap and pressure testing the cooling system. Nothing helped, so I finally broke down and took the coach into a RV repair center to have the CAC and radiator completely removed, separated and cleaned out.
Last week we left Apache Junction for Show Low where we will be spending our summers evading the suffocating heat of the greater Phoenix valley. Hwy 60 has several long hills, most notable being the long decent into and back out of the Salt River Canyon. It was 95 degrees when we started into the canyon, and we were pulling a Jeep Wrangler 4 dr Unlimited. Crossing the river and starting up the other side my stomach was in a knot. This is exactly the scenario where we would have been in deep kimchi before, overheating almost immediately. But nothing happened. The gauge rose to the upper portion of the normal range, the engine diagnostics indicated a temp of 218 degrees, and I was all smiles.
So, if you are plagued like I was, frequently overheating and unable to resolve it, get that radiator and CAC out of your coach, separated and cleaned out.
Take a look at these pictures of the two components and you will see why Simple Green or other cleaner efforts are generally ineffective against plugged radiator fins.

And I was nervous seeing the occasional 206 for both Engine and Transmission. I feel a bit better now but sometime down the road they will have to come out....Hopefully when I get out of California and very high labor rates...

Timaz · 06-10-2021, 06:38 PM

When I first bought my coach in 2017 It ran hot (220) climbing sunset point in 110 temps. It also had no boost. I changed the wax valve and fixed the temp but not the boost. Turns out the turbo was bad and I had a 8" long crack in the CAC. Since then I have been in very hot temps pulling 6+% grades and have never busted 197. And this motor gets pushed pretty hard. So I guess I'm really doing good.

Tim

Andersku · 06-11-2021, 07:55 AM

Quote:

Originally Posted by StuartT

A number of DP members, including myself, have been plagued by overheating on the side radiated ISL 400 engines. We use every trick in the book to try and avoid that overheating warning buzzer, which usually starts blaring around 230 degrees. We are usually in hot weather or high altitudes or both, and we shift down, turn off the ac, call for max cabin heat, let off some of the throttle, and when all else fails we pull over, let the engine cool down, then have the DW drive the dingy the rest of the way up the hill to lighten the load.

I tried all the remedies; complete engine flush, new thermostat, installing a wax valve controller, doing multiple Simple Green radiator fin cleanings, checking fan blade rpms, checking the water pump for coolant flow, replacing radiator cap and pressure testing the cooling system. Nothing helped, so I finally broke down and took the coach into a RV repair center to have the CAC and radiator completely removed, separated and cleaned out.

Last week we left Apache Junction for Show Low where we will be spending our summers evading the suffocating heat of the greater Phoenix valley. Hwy 60 has several long hills, most notable being the long decent into and back out of the Salt River Canyon. It was 95 degrees when we started into the canyon, and we were pulling a Jeep Wrangler 4 dr Unlimited. Crossing the river and starting up the other side my stomach was in a knot. This is exactly the scenario where we would have been in deep kimchi before, overheating almost immediately. But nothing happened. The gauge rose to the upper portion of the normal range, the engine diagnostics indicated a temp of 218 degrees, and I was all smiles.

So, if you are plagued like I was, frequently overheating and unable to resolve it, get that radiator and CAC out of your coach, separated and cleaned out.

Take a look at these pictures of the two components and you will see why Simple Green or other cleaner efforts are generally ineffective against plugged radiator fins.

I had this problem for years and I also tried every trick in the book including having Cummins Northwest in Medford Oregon service and clean the radiator. I shared the dread you felt at the thought of a long climb on a warm day or even a short climb on a hot day. Nothing worked including the Source Engineering controller until the CAC and radiator were removed and cleaned. The pics from my coach were similar to yours.
Since then, I use the simple green (purple) cleaning approach as suggested on this forum at least once a year and keep my fingers crossed. Recently, someone on this forum recommended using a leaf blower to help push the cleaner through and I intend to try that on the next round. Congratulations on the fix, I know exactly how you feel.