Overheating

Wildman1 · Jul 31, 2007

Okay I need some help with this as I am about done with ideas.
Before I repaired the plenum gasket on the intake manifold of my 5.2L it never over heated. Now since I have gotten that done when ever the Jeep is under a heavy load it will overheat. The electric fan is working and pulling the correct direction, I had installed a 185* thermostat but pulled it and put a stock 195* back in. The radiator is new and was cooling the engine fine before. The coolant is the pre-mix stuff which is what I had in it before also.

So ideas? I haven't tested the radiator cap but it is new. Other ideas?

cisco · Jul 31, 2007

I'm no motor tech but will throw this out. How do the plugs look? Is the motor running lean? Could something have happened with the intake that changed the air fuel mixture?

Wildman1 · Jul 31, 2007

This is what I have been thinking but I haven't pulled the plugs. And if it was running lean how would the plugs look? But then the next question is; why isn't the computer running the engine right? This is a 97 TJ with a 99 5.2L V-8 out of a Dakota. All the computer stuff is there.

Not Jobless · Jul 31, 2007

Definately test the cap, and/or just replace it and check the water pump while you are at it.

When you changed the t-stat are you sure you got all the air out as well?

Wildman1 · Jul 31, 2007

How do I test the water pump?
Cap, Rotor, Wires & Plugs are all new.

hwcurtice · Jul 31, 2007

Wildman said:
How do I test the water pump?
Cap, Rotor, Wires & Plugs are all new.

Thats a pressure test. Not sure how to do it now, but in the old days, when the engine ran the fan too, if your fan felt loose, the bearings in the water pump were bad. I know if you put a pressure tester on the radiator fill, if it never goes up, that a good hint something is bad, and most likely, the culprit is the pump.

If you have a sealed system

uke: I'm not sure how to test that.

Can you wiggle the pully the moves the water pump?

Sorry, not much of a mechanic here on new school ways. More a fan of the old stuff...

Not Jobless · Jul 31, 2007

Test the water pump...just replace it I guess. It's kinda hard as the only way you are going to know is to take the cap off the rad and see if water is moving in it...which obviously means the t-stat will be open and more than likeley pressurized.

I'm sure there's some overpriced tool out there for testing them.

Wildman1 · Jul 31, 2007

I have had the cap off a couple of times wondering if I had gotten all the air out. I think I am getting flow but the last time I had it running with the cap off it almost looked like it wasn't flowing.

Binder · Jul 31, 2007

It won't flow untill it's warm enough to open the thermostat- 195 deg.

Wildman1 · Jul 31, 2007

Got that. I know it isn't going to flow until the thermostat opens. What I am not sure about is how to check the waterpump. And because this is only doing this under load makes me think water pump or running lean.

skinny_pedal · Jul 31, 2007

any leaks anywhere. put a pressure tester on the radiator and start checking?

blackcj71 · Jul 31, 2007

Wildman said:
Okay I need some help with this as I am about done with ideas.
Before I repaired the plenum gasket on the intake manifold of my 5.2L it never over heated. Now since I have gotten that done when ever the Jeep is under a heavy load it will overheat. The electric fan is working and pulling the correct direction, I had installed a 185* thermostat but pulled it and put a stock 195* back in. The radiator is new and was cooling the engine fine before. The coolant is the pre-mix stuff which is what I had in it before also.

So ideas? I haven't tested the radiator cap but it is new. Other ideas?

Whats the temperature???

Wildman1 · Jul 31, 2007

Well it use to run at 210 all the time. It hits 240 and sometimes will stay there but other times goes to 260.

The system has been pressure checked. No leaks after months of tracking all kinds down.

blackcj71 · Aug 1, 2007

since you did tstat i'd be looking at hte w/p next, but i'd be doing block check before you go and start throwing parts at it. You can always pull the w/p off and see if its broke etc.

Wildman1 · Aug 5, 2007

My water pump was starting to go bad. The bearing was making all kinds of noise. And even with it off the bearing is noisy. So I have the Flow Kooler water pump ready to be put on tomorrow.

Hopefully this will take care of my overheating issues.

cisco · Aug 5, 2007

That will be interesting to find out. Make sure and post the results.

I cant figure out how a gravely bearing effects the function of a water pump. It seems like the bearing would have to be totally gone to cause problems. Other than it seems like over heating could be caused by the seal leaking and maybe causing it to loose a little pressure and loss of coolant, or the fins corrode and break off, or some kind of gunk blocks up the passage ways.

Not Jobless · Aug 5, 2007

I would have swapped out all that stuff (belts, hoses, water pump, ignition parts, etc...) when you did the motor swap.

Wildman1 · Aug 5, 2007

Jobless said:
I would have swapped out all that stuff (belts, hoses, water pump, ignition parts, etc...) when you did the motor swap.

Well "I" didn't do the swap & the shop that did said it di put new hoses & ign parts on. But when I go the Jeep back I took the A/C pump off because I wasn't going to run A/C so I put a new belt on. The cap that was put on got cracked so I ended up replacing everything anyhow. This will be the last thing on your list to get done.

Not Jobless · Aug 5, 2007

Wildman said:
Well "I" didn't do the swap & the shop that did said it di put new hoses & ign parts on. But when I go the Jeep back I took the A/C pump off because I wasn't going to run A/C so I put a new belt on. The cap that was put on got cracked so I ended up replacing everything anyhow. This will be the last thing on your list to get done.

Just re-enforces the old saying...

You want it done right, you better do it yourself :beer:

Wildman1 · Aug 5, 2007

Jobless said:
Just re-enforces the old saying...

You want it done right, you better do it yourself :beer:

Yep but when I had it done I wasn't in a position to do it myself. I can do a lot more of my own work now. Last year in March I wasn't able.

And we already know my Jeep is to complicated for you. But I am glad I have half the crap I do. :beer: :beer: