Community Forums

DMTTRANSPORT · 09-01-2015, 08:37 PM

Quote:

Originally Posted by jd956jd956

A diesel requires A LOT of air to run efficiently, therefore, when climbing hills, the RPMs have to be up there toward the maximum, to ensure plenty of air, no engine lugging and very little if any over-heating.

Please do not take the above to mean that if your engine's maximum RPM is governed at 2500 RPMs that you need to run it at 2400 or 2450... Mine is Rated at either 2500 or 2600 and it does VERY well between 2000 and 2200 RPMs. The temp drops when you back out, because it is no longer starving for air.

The reason an engine (Gas/Diesel) temperature climbs when the Vehicle Climbs is simple, your pushing on the pedal to keep your speed therefore increasing EGT (Exhaust Gas Temp) creating more heat in the engine, backing out of the pedal = less fuel/gas = less heat = lower coolant temp.

Mr_D · 09-01-2015, 08:52 PM

Quote:

Originally Posted by jd956jd956

Be CERTAIN that when climbing hills you are at +2000 to 2200 RPMs otherwise the engine will be "lugging" which absolutely will cause the temperature to rise! You will have to manually downshift to keep the RPMs up. I have climbed Wolf Creek Pass, Colorado twice and had zero problems. It is a long climb and my engine ran like a sewing machine at about 2200 RPMs in second gear and NO temperature fluctuation

I found the above to be true with our '02 DSDP with ISC 350 with Banks (435 hp and 1200 lbs ft torque) With the Magna it doesn't seem to matter. Cruise control and economy mode (most of the time) work for everything we've done so far.

SteveLevin · 09-01-2015, 10:39 PM

Spartan is definitely awesome and will send you tons of info!

I had a similar problem to you with my MM chassis, it turned out there's like a pressure distribution widget that also keeps pressure to the power steering that was going bad over time.

The first thing to check (and I think you can use a timing gun or similar for this) is that your fan speed at high RPM is keeping up. My failure was originally deceptive in that at low speed/idle the fan was turning just fine. But at 2000rpm it was running much slower than it should have been, hence the issue would show up more on climbs.

Steve

gptexas · 09-03-2015, 07:55 AM

I have been thru lots of $$$ on this subject. Finally disconnected the solenoid control wires. My fan was only rotating 280 rpm's and went to high speed 570 rpm's after disconnecting those wires. Engine now runs 180 to 190deg. You can purchase a "digital photo laser tachometer tester" on E-Bay for under $15.00. Check your fan speed and then troubleshoot.

FORTRIDER · 09-16-2015, 09:47 PM

Quote:

Originally Posted by jd956jd956

My 1997 Spartan Mountain Master with Cummins C8.3 has no electronics on the engine and the hydraulic radiator fan is indeed controlled by engine RPM. It is regulated by the hydraulic pump which runs off the engine.

OP - Attached is a Spartan diagram that might be helpful if it matches your 1995 year model mountain master... hope so and please let us know what you find...

As this looks like the system I have I will give Spartan a call to see how to test the system. Also, received infrared tach today and will give that a test tomorrow or Fri to see what the fan is doing at speeds.
1998 American Eagle C8.3