overheating issue

90scmn12

Registered User
so i was driving home from work today and my car started over heating on the highway so i pulled over and let it cool down the temp went back down and i drove home the temp kept going up and down but spiked especially when i would load the motor on hills. not sure what the problem is ive already flushed the coolant with in the last month ive pressure tested the cooling system and it held ive even unplugged the ac comp so i could force the fan to stay on i dont get it im guessing t-stat but maybe im missing something?
 
T-stat is either stuck, water pump is either old and not flowing well but impellers should be metal not plastic so I doubt that. The other option..... head gasket. Do a compression test. Check the oil for water. Check the coolant for oil.
 
What color is the coolant now?

Done any repairs lately?

Does the fan run if you disconnect the ECT over by the A/C compressor?

You say it overheated today - why did you flush it a month ago?
 
temp kept going up and down but spiked especially when i would load the motor on hills

Kinda sounds like a head gasket going out or cracked head. Had the exact same problem.
Took it on vacation to Colorado, it would over heat going up the foot hills to the mountains and then cool off(until it boiled all the coolant) on the way down.

Cracked head and blown gasket was the issue
 
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That'll do it :)

Any trouble getting the housing/gasket to seal?

Thanks for the follow up and good luck.
 
I put rtv on both sides of the gasket to make sure it sealed I also bought a rad cap with a relief on it to keep purging the air out thanks for the input though I was praying the hgs didn't blow
 
Have the HG's been done yet? Hopefully the t-stat was the problem. In my case it was not. My t-stat was stuck open and broken on one side. i had to take the car to a shop since we were on vacation. they did a block leak diwn test and a cooling system pressure test as well as tested the cap(all showed great with no problems) i had them replace the t-stat since that seemed to be the only logical thing left, 2 days later it started over hearting again. we got the car back home by trailer from colorado. I put in a new radiator thinking that it might be plugged. This fixed the problem for maybe 4 days. My only option left was to do a compression check. Passenger bank cylinders had a compression of(front to back): 125-70-110. I knew then that it was a HG out.
I tore it down and found 3 cracks in the head and the gasket was destroyed!

Hopefully this isn't your case. Just be prepared to fix it I guess. It's all you can do, at least it's not a bad job to do.
 
Ya that fixed it and the engine that's in it is a ford remaned that was put in 1998 it has under 100k on it so hopefully it'll be fine
 
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