I'm not happy with my cooling system. Just drove from California to Phoenix and it hits the third hot line over long hard climbs, and requires OD off, above 2700 rpm, and below 60 mph, otherwise the temp hits the roof. Engine has 172k miles, vehicle s 12000 lbs. Tranny temp is good. EGT is good. Would like to go over those mountains faster :-)

Radiator is new. Stuff in front of radiator: intercooler, then ac condenser, then aux transmission cooler and steering cooler with fan.

Question 1. What devices can I add to help my cooling system?

Question 2. What service procedures can be done to eliminate the cooling symptoms. In other words, what are the possible causes of overheating on long hard climbs.

 

How far do you have the injection event timing advanced? Substantial advance will drive up the heat available to be converted to work in the cylinders, thus driving up the engine coolant temp.

 

Do you have a shroud? That single item alone can make all the difference in the world.

But you could also have a failing clutch assembly on your fan. If it's not locking up properly when the heat begins to rise, and therefore start drawing more air, then it will slowly begin to build up heat.

Also what kind of fan..stock 1st gen unit? I would recommend the 2nd gen fan and clutch fan assembly. I got both mine off e-bay and couldn't be happier.

 

My dad had a 440 powered, similar era motorhome and had a bear of a time with engine temps.
Could it be related to the chassis design?? That engine was surrounded in ky dads rig!

 

Water injection, water sprayed in front of radiator, add an oil cooler to the trans. Assuming you have the things above working. Mike

 

I swapped the engine at 150k miles. Don't know if timing was advanced. The IP seemed in original position. I had a hell of a time re moving the IP from the case when I recently resealed it.

Is there a timing light that I can use to check the timing? Or do I have to use a dial ind at the rear of the pump? I'd rather leave that IP alone for now :-)

Edit: i have an m and h spacer waiting to be installed. Im afraid it will just worsen the engine temps.

 

I have the original fan shroud in there. I think I dd a good job sealing the edges where they meet the intercooler.

As far as the clutch is concerned I hear the fan roar when the engine temps start climbing. So I think the clutch is engaging. It is the original 1st gen fan

Is the 2nd gen fan more efficient? Moves more air?

 

Could be. It's a doghouse design :-) where the top of the engine is enclosed. However, there's a lot of space on the sides for air to escape. And the chassis is lifted so it allows a lot of air circulation. The front grille allows massive air into the coolers.

 

Do you mean water injection into the intake / intercooler? Would like to know more!

Is there such a thing as auxillary engine cooler - i have room in front. My aux trans cooler and fan is in the middle, I could move it to the side to make room for another fluid cooler with fan for engine cooling.

 

In case it's a factor, the motorhome has a water heater / exchanger plumbed into the coolant lines. I would think that would help, not worsen the situation.

 

One more thing, egt is good, in the low 1000s, as long as the engine runs above 2700rpm OD off. Egt shoots up to 1300 when on OD, and engine temps would get pegged to max, if I let it.

 

The biggest thing in my experience is the auto trans. I just pulled a 1500 chevy on a 2500lb trailer 300 miles without a cooling fan in my manual trans truck. It was around 30F so that probably helped a bit but temps didn't even creep up on long grades. My 2wd auto truck doing the same type pull(weight an rout) with a functional fan would start getting hot trying keep the same speeds up those grades. An upgraded torque converter would probably help a bit and a huge trans cooler would help take some of the stress off the engine cooling system.

 

My experience with the symptoms that you describe is not enough radiator capacity. This could be by design, 1 or 2 core, or loss of capacity because it is partially clogged up. I have a mc that would run at perfect temps around town, but as soon as I went on a long trip, the temp would slowly rise to overheating. After throwing some parts at it, I replaced the radiator and all problems stopped. The posters above mentioned the shroud, but how is the other side? Can the rad freely suck in air? We had problems with rear mount fire engines because the radiator faced the rear and got no forced air input, good luck...Mark

 

Fan clutch working?

 

is rsm rancho santa margarita?