2003 Newmar DSDP Spartan side radiator heating problem under load

[RV Wally]

I posted this about 2 months ago and have more info. Scan gauge confirms the gauge is pretty accurate and got to the top of the hill and scan gauge said 215. Stopped at the top and checked top of thermostat with heat gun and it was 214. Bottom hose was 190, and runs 180 on flat, just changed both hyd. Filters in and out of tank. 4 years ago install new radiator, charge air cooler new had a leak thermostats and they are in right side up. Just wandering if anybody has one of these chassis, (they came under 2000 to 2003 newmar ds, fleetwoods any coach with a spartan chassis with the 350 isc and side radiator) and is having the same problem. I have checked cooling system pressure with a 15# cap never gets over 13#. Ambient temp that day was 95. I have rebuilt over 100 diesel engines and don't believe it's a head or head gasket problem and spartan is no help.

[Mr_D]

Had a 2002 DSDP on the Spartan, traded it in in the present rig in 2016. I installed the Banks Power Pack in 2006. Never had any overheating trouble before or after the Banks install. In fact it was the most trouble free unit I've ever owned.

[rvbiker45]

What was the RPM while going over the hill? And, the speed?

[RV Wally]

2100 4th gear 45 mph

[rvbiker45]

It could be possible that the fan is not getting into the high speed mode. It is my understanding that the fan has two speeds, controlled by a fan controller that is automatic. I do not know what causes the fan to go to high speed, but RPM is the probable trigger. I have heard of several operators where the controller malfunctioned.

[RV Wally]

According to spartan the 2003 with 350 isc only has 1 speed and runs with engine rpm. Yours with the isl has a computer controlled valve that monitors temp and speeds up the fan when temp hits 210 and you have a bigger cooling package, your lucky i all ways seem to by 1 year to early. But because mr d had the same thing and never had a heating problem even after the banks install is getting me thinking. When i installed the new radiator i re plumbed the the cooling piping so that the water would flow from the thermostat to the top of the radiator and from the bottom back to the engine like all other cooling systems are plumbed. It was plumbed from the bottom to the top from the factory, maybe now the water is going to fast through the radiator and not getting cooled enough, we had that problem on the race cars and had to install a restriction in the top hose.

[Ray,IN]

Originally Posted by RV Wally

According to spartan the 2003 with 350 isc only has 1 speed and runs with engine rpm. Yours with the isl has a computer controlled valve that monitors temp and speeds up the fan when temp hits 210 and you have a bigger cooling package, your lucky i all ways seem to by 1 year to early. But because mr d had the same thing and never had a heating problem even after the banks install is getting me thinking. When i installed the new radiator i re plumbed the the cooling piping so that the water would flow from the thermostat to the top of the radiator and from the bottom back to the engine like all other cooling systems are plumbed. It was plumbed from the bottom to the top from the factory, maybe now the water is going to fast through the radiator and not getting cooled enough, we had that problem on the race cars and had to install a restriction in the top hose.

Return coolant flow to normal bottom entry, top exit for better cooling efficiency.

[RV Wally]

Originally Posted by ray,in

return coolant flow to normal bottom entry, top exit for better cooling efficiency.

yes i have been thinking about doing that, does yours have the side radiator and have no heating problems

[Ray,IN]

Originally Posted by RV Wally

yes i have been thinking about doing that, does yours have the side radiator and have no heating problems

Correct!

[MoePo]

I had a 02 DSDP that had opposite issues of what your having. My motor wasn’t getting up to operating temp. There is a priority valve that diverts hydraulic fluid to the power steering and cooling fan. Follow the hose from the hydraulic motor on the fan you will see a manifold block. That’s your priority valve Perhaps your cooling fan isn’t spinning fast enough? I ended having to slow my fan down with a few turns of a Allen key. Maybe you need to do the opposite.

[RV Wally]

Yes i have seen that valve did not know it was adjustable, i will check it out. Did you turn it in or out.

[MoePo]

Originally Posted by RV Wally

Yes i have seen that valve did not know it was adjustable, i will check it out. Did you turn it in or out.

I can’t remember. I want to say I turned it counter clockwise. But It definitely slowed it down. Operating temps went from 180 to 195. Hard pull would bring me up to around 208ish. Never higher than that. Most of my travels were up and down i77 in the Smokey mountains

[RV Wally]

I ordered a digital rpm laser gun to check rpm, I will play with it when I get it.

[RV Wally]

Did oil leak out when you unscrewed the allen plug?