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Nicko 03-23-2012 10:23 AM

Engine running way to hot! Please help!
hey guys! i put a post up in the YJ section but i think it be better here casue this is a general problem. I have a 1994 Yj 4.0 and it runs realy will even hit the red when going slow in traffic. as soon as i get up to like 30 mph it backs off ever so slightly but is still way past half. not sure if my radiator is clogged but i flushed the cooling system a month ago so that would have taken care of it right? any idea what the problem might be? i thought maybe a clutch fan? kinda worried and scared to drive it...

WatchThis! 03-23-2012 10:59 AM

If a good flush and then a good cleaning of the outside dont do it you could have a thermostat sticking on you. Or your radiator could be to corroded for a flush to work.

Iceman 03-23-2012 12:31 PM

Check your water pump see if the weep hole is weeping.

Dassquatch 03-23-2012 01:06 PM

Check these in order:

1 - Coolant: Check level, if you can't see any in the radiator, that's your starting point. Should be green (or whatever the original color is) and not smell "burnt."
2 - Look for puddles (of coolant) underneath the Jeep. If it leaves one, look for the source.
3 - Radiator leaks: Check for those, look for wet spots on the radiator. Also check the cap. And the rim at the top of the radiator.
4 - Hoses: Look for cracks and feel for soft spots (when it's cool).
5 - Water pump weep hole and gasket surface.
6 - If you hear a pulsing or thudding, it's probably the thermostat. I would replace the thermostat and hoses anyway, if they're old.
7 - Exhaust: Look for white smoke from the tailpipe. If it's there, it's probably the head gasket.
8 - Oil: If it's milky, or a light brown color, it's definitely the head gasket, quit driving it and replace the gasket.

I've had coolant leaks and issues in alot of vehicles. Just check everything thoroughly, and you should find the leak/problem.

Nicko 03-23-2012 03:10 PM

its not a leak...its as tight as a drum. i changed the fan clutch thinking it could be that but it didnt do anything it s still hitting the redline. the only ither thing for me to try would be the thermostat...sure hope i dont need a new radiator.

WatchThis! 03-23-2012 06:01 PM

you can go ahead and just pull it out and run it without one and see if that is your problem... but if you do have to change the radiator you might as well change you thermostat while your at it

Iceman 03-23-2012 06:51 PM

My rule always was never change the a radiator without changing the thermostat as well, that being said you can pull the thermostat to see what happens.

Nicko 03-23-2012 07:29 PM

True! I think it is the thermostat because when I start the engine with the radiator cap off i can see a current...however in about 20 seconds coolant starts to over flow out the cap hole...that's gotta be a stuck t-stat.

Sparkplugg 03-23-2012 08:49 PM

It doesn't bubble, does it?

Iceman 03-23-2012 11:10 PM

Might want to test the cap too I had one or two of them go bad on me before

Nicko 03-24-2012 12:12 PM

I changed the t-stat but it's still overheating. I also noticed an oily film in my coolant and that my radiator seemed a little my engin shot?? :(

Dassquatch 03-24-2012 10:25 PM

Doubt it. Change the radiator cap and flush it again. If it is the radiator, check with Rock Auto for a replacement. If there's oil in the coolant, it's probably the head gasket. That's a fairly large job, but not a difficult one.

Dassquatch 03-24-2012 10:27 PM

Oh, and get all of the measurements from the radiator. Length, width, thickness, inlet, and outlet sizes. Also, get the bolt pattern measurements, just in case.

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