Engine/Transmission (1994 - 1998) "97"12valve overheating problem

[SubZero]

I have a 2002 2500 24 valve and my dad has a 1997 2500 12 valve, which he bought used about a year an a half ago. Lately we've been having problems overheating with the '97. I don't thing it has any power upgrades (from the previous owner), as near as I can tell from looking over the engine and injection pump. I removed the resonator and muffler, changed the thermostat, air filter, and checked everything I can think of, all of which has helped. But on long uphill pulls with a 30' fifth wheel camper in tow, it still overheats. And when driving around empty or loaded on level ground the temperature gauge slowly bobs up and down from about 160 to 200 degrees, but it never overheats. My '02 warms up to 190 and stays there. Is this gauge bobbing a normal trait of the 12 valve engine, or am I missing something? If anyone as any ideas please let me know, Thanks

 

[Joe G.]

The gauge cycling is normal, but that seems about 20 degrees higher than usual. It can heat up pulling a good load up a long steep hill, especially if the RPM is low. You might drain a couple of gallons of coolant and look down in the radiator to get some idea how bad the crud accumulation is.

 

[illflem]

The fan clutch might be shot. When it cycles on the roar is obvious.

 

[WadePatton]

Pull the radiator and see how plugged up it is. Yep, it's a bit of a pain, but so is overheating. While you have it out, get it cleaned out by a radiator shop, if it is cruddy inside at all.



While you've got that out of the way, you can pull the timing cover and check the KDP-if not already done.



Did you check the new thermostat before you put it in? I always do. Dip it in boiling water then cold water and watch it work.

 

[bmoeller]

Could also have crud in the fins on the other coolers blocking air flow.

 

[Extreme1]

Ditto on what illflem said. Been there, done that. If you don't hear the fan clutch kick on, that's the problem. How hot does it get?

 

[Deezul1]

I dont know if my fan even works as I cant get it hot enough to turn on even when towing the travel trailer. It sure sounds like a plugged radiator as these things just dont get way warm

 

[RedRamer]

Is there a way to check if fan clutch is shot?

Last summer I also got a couple of mid-high temps on long grades pulling my trailer.

 

[BrandonF]

high water temp

might have almost spit a head gasket... how many miles are on it??

the beginning of a blown headgasket is increase in water temp. at significant pulls or wot... . doesn't mean it will puke oil or water just high water temps.



the 12 valves rarely get plugged up from bugs. very common in the 24 valve.



danelle

 

[illflem]

Originally posted by RedRamer

Is there a way to check if fan clutch is shot?

Last summer I also got a couple of mid-high temps on long grades pulling my trailer.

The fan should spin with slight resistance when the engine is warm. If it continues spinning after you give it turn or doesn't turn at all it's shot.

Don't be alarmed if you don't hear it kick in, mine has only locked up a handful of times in eight years only when the temp hits around 210°.

 

[SEmerson]

Also make sure the tc is locked on a hill. If not it will put alot of heat in the water.

 

[WadePatton]

Re: high water temp

Originally posted by Danelle



the 12 valves rarely get plugged up from bugs. very common in the 24 valve.

danelle

Could you elaborate on that a bit? What's the difference?

 

[TKemper]

Did you check the radiator cap. If the cap is weak it can run hot. If you don't have a cooling system tester just buy a new cap. They're cheap enough. Todd

 

[Brandon]

Re: Re: high water temp

Originally posted by WadePatton

Could you elaborate on that a bit? What's the difference?

I think 24 valve has an aluminum core and a 12 valve doesn't.



danelle

 

[Joe G.]

The aluminum core radiator may have just superceded the old version for all years. When I ordered a new radiator for my '95 it was aluminum. My old one was not.

 

[WadePatton]

and bugs stick to aluminum better?

 

[Joe G.]

It would take a LOT of bugs to reduce the cooling of one of these radiators. I think he has crud plugging up the tubes. Could be the lower ones are all pluged up.

 

[SubZero]

Thanks for the ideas

Thanks to everyone for their suggestions about my overheating problem! Now that it is winter here, we don't tow anything, and we still need a piece of cardboard in front of the radiator just to get some desent heat in the cab. So when the weather warms up I'm going to start by flushing and inspecting the radiator and replace the cap. Hopefully that's all that'll need to do. If not I guess it's time to replace some parts.