Engine/Transmission (1994 - 1998) engine running very warm-plugged heater core?

[JRaymond]

my 97 2500 4x4 auto seems to run very warm(close to overheating) only while plowing snow-i've changed the themostat but no difference-i'm wondering if the heater core many be plugged because i'm really not getting real strong heat even though the engine is very very warm. anybody else have a similar problem? any ideas would be helpful-thanks j raymond















97 2500 std cab 4x4 auto-stock for now but not for long

99 f350 7. 3

2000 ford lightning 450rwhp

 

[hsmith]

The heater core can't cause overheating, in my opinion. Only a small amount of coolant passes through it. Sounds more like a thermostat problem, which would also cause you to not get cab heat.

 

[JRaymond]

that's why i changed it-installed a carquest brand someone suggested to get a factory dodge or cummins thermostat-what's your thoughts? thanks jraymond

 

[Moparsean]

I have seen corrosion on the inside of the rad,so bad that enough coolant can't flow threw fast enough. Or the clutch fan may be junk. Drain the rad a tad and look down in that puppy. Mine was really bad,but... i had over 440k when it plugged,and i think the last owner skipped some coolant changes.

make sure there is no oil and junk stuck between the rad and the intercooler.



does your tensioner have enough spring still left in it?



The last thing,i could suspect is a slipping impeller on the waterpump inside... havent seen it on a cummins 12 valve but don't mean it can't happen. Common on caterpillar engines. this is rare but plossible.



one last thing is this overheat issue down the road or plowing a driveway. we had a ford once at work that would heat up a bit with the plow on and going down the highway (blocked air flow)... i doubt that your issue,just puttin it out there



how hot is hot? I run 195 most of the time,summer or winter.

 

[Moparsean]

One last thing i thought of,make sure you are not over 70 percent anti-freeze mixture... . 50/50 is good to -34..... more is NOT better. The WATER cools the engine,not the glycol. If you don't believe me... NASCAR and drag cars use only water (the rules) and they do fine

 

[Vaughn MacKenzie]

JRaymond do you hear your fan fully engage when the engine heats up? Maybe the fan clutch is bad. Also if you've never done it before the radiator should be completely removed from the truck and pressure washed. . . they can get pretty gunked up over time.

 

[JRaymond]

the fan clutch does come on only before the gauge gets into the red-when should it come on? my 95 truck would only run around 190 where this truck runs all the way over to the far safe side and sometimes close to overheating but it takes quite a while before it gets that warm and if you stop plowing hard and let it idle it will cool down very quickly?

 

[Missouri Mule]

On the auto trans you have a remote trans cooler that dosen't hook in to the radiator right. I was just thinking that an over heating trans would cause hot coolant temps.



If you got hot coolant temps you should be able to get warm air into the cab. So that leaves you with a bad T-stat, the temp door broken or not working properly. Never heard of heater core getting plugged up unless your radiator is in bad shape. (On my 82 Buick Regal I used the heat to cool off coolant because radiator was in bad shape , I put in a new radiator to solve problem. )

 

[Moparsean]

sounds like the clutch fan is lazy/late to come on,make sure the fan can get air threw the rad. The clutch fans are cheap,i paid 67. 00 at advance auto for mine,but they will have to order it i'll bet. You may want to verify the accuracy of the gauge too. See if anyone you know has a non contact infer-red thermometer,and shoot the top rad hose when your warmed up,see if its anything close to what the dash says. i'd put a genuine cummins t-stat in too,i have heard horror storys on the will fit... ones.

 

[Hoefler]

If I read your post correctly, you said you are overheating with little heat from the heater core. If this is the case, I would suspect you have air trapped in the system some where. I would check the heater core first, since you have little or no heat. The lines could be reversed on the heater core, the supply should be on the bottom and the return on top, to allow the air to purge. Try running the engine with the radiator cap off or loose until the thermostat opens. Allowing the system pressurize before all the air is out, often gets air trapped and takes forever to work its way out. You may even have to take a line or fitting loose until you get coolant running out.

 

[Skydiver]

JRaymond, Next time the engine heats up, look inside the plastic coolant overflow reservoir. Do you see bubbles flowing up from the bottom?



I had a truck years ago with weak or no cab heat. It had bubbles continuously coming up in the plastic jug.

 

[wcjp]

JRaymond do you hear your fan fully engage when the engine heats up? Maybe the fan clutch is bad. Also if you've never done it before the radiator should be completely removed from the truck and pressure washed. . . they can get pretty gunked up over time.

This is to remove the oil residue that's collected on the outside of the radiator. The oil attracts dirt which restricts cooling. I'm going to add the waterpump to the mix. Could help explain lack of flow to the heater core.

 

[biggy238]

Sounds like everyone has had each heat problem happen.



I replaced my water pump not long ago. It was to the point that the water temp would rise but there wasn't enough pressure to kick the t-stat open, and/or force water through the neck into the radiator. The pump had just started to whine and was not leaking at that point.



While I was waiting for the new pump to come in, the pump cut loose 30 miles from home. Heat, a water leak and a lot or cursing happened all at once. I drove it directly to NAPA and we swapped it in the parking lot. (personal friends of mine own it)



Seems like you will have to do more investigation to determine the exact cause of your problem

 

[JRaymond]

i did check the heater cable/door and seems to feel and sound like its shutting and closing fully-i think i'll swap in a new water pump and a cummins thermostat and also check the hoses on the heater core to make sure there routed/connected correctly-i do know that there shouldn't be any air in the system because i drilled a very small hole(less than 1/8'') in the thermostat when i installed it to relieve the air caught in the system

jraymond

 

[biggy238]

I always unhook that small cross-over hose at the t-stat while i'm filling mine. I could be wrong, but I fealt it did a good job bleeding the system.

 

[tgordon]

Just a thought, and you may have already done this, but check the temp sender. I do not know how they react when they go bad, but it might be reading on the hot side while the engine is still safe. I would prefer it to read that way rather than cool.

 

[LMcCary]

SKYDIVER wants to know if you can see bubbles in the bottle. If it is bubbling, the head or gasket is leaking. This will cause all of your symptoms.

 

[Skydiver]

LMcCary, You know it !



Been there, done that on a 1979 Chevy Diesel. Heat cometh, heat goeth.

 

[Calebh9806]

Where Excactly is my t stat located ?

 

[hsmith]

Engine end of upper hose. Remove alternator to access.