weird overheating problem

[craigwhite89gt]

A week ago my car overheated for the first time since i got it, so i changed the thermostat with my dad. He said we should keep the cap off the radiatior to see if the fluid is circulating. Well after the car started to get to normal temp the fluid started gushing out, something he said shouldnt happen. So i filled it up with fluid again and and put the cap on and it has been working good. Oh and the thermostat i put in is a autozone cheapeee. But anyway now after the car has been sitting for a while like 6 hrs or so. When the car starts warming up the temp gauge rises slowly then fairly fast shoots all the way up for about 30 seconds to a minute then the temp goes back down. And when the temp is all the way up i dont feel my heat like the fluid isnt circulating... So anyone have any suggestions, my buddy said it might be some sort of temp sensor. but i need some help !!

Thanks
Craig

 

[bmorrisj]

the water temp sensor is on the front/driver side of the lower intake manifold. also check the fan clutch, if you can spin the fan easily by hand(no stiffness) it's bad. and also worry about blown head gaskets if you overheated too much...

 

[jmuva44]

I know you have probably tried this but make sure for certain that you have gotten all air out of the system. Sometimes it may take three or four cycles of starting it and refilling it. Squeeze the upper hose before it gets hot. that helps get some air out. And antifreeze gushing out the top has happened to me several times. I dont think its a big deal. Just turn the car off, refill it and start it again.

 

[makarov]

jmuva hit it right. I recently changed the radiator and stat, and with the cap off it surged when the stat opened, gushing coolant. Turned it off, refilled it and no problems. Perfectly normal.

The temp sensor is inexpensive, as is checking the fan as bmorrisj stated. If you are worried about a blown head gasket, take it to a shop and have them due a "products of combustion" test on the radiator. It will detect gas fumes, oil and other contaminants in the coolant. If detected, a compression check will normally pinpoint which bank and cylinders are affected, but it's a good idea to do both sides if that's the case.

 

[IndyBlk5.0]

i have the exact same problem as you do. Gradual heating then all of the sudden it rises really quickly and overheats, no heat from heater, water gets pushed out of the radiator with cap off.... I pulled my head gaskets and found that they were blown in 6 places. Do a leakdown test, (although that came back negitive even with my blown head gaskets) do a combustion gas test in your radiator, and also is it constantly bubbling with the cap off? i didnt have any water in my oil, check for that though, it will look like a milk shake, i had no oil in water to speak of. Agian, it was headgaskets, i replaced my water pump, sensor, t-stat, burped the system repeatably... So that ended up blowing my heater core up. but i replaced that... agian, compression test is easiest, if its off by 10% on any of the cylinders i would say you have a problem. products of combustion test costs about 40 bucks...

 

[craigwhite89gt]

Thanks for the replys, ill check it out tommarow.

 

[IndyBlk5.0]

it is not uncommon for head gaskets to be blown in these older mustangs i see new cases everyday!

 

[90mustangGT]

I was icing my intake at the track, then when I pulled to the staging lanes the temp gauge shot up to red rather quickly, so I aborted, and when I opened the hood the engine was cool. I think the sensor or guage must have shorted up with the water from the ice, it never worked right after that. I got a autometer temp gauge now, works much better.

 

[Grand Tourismo]

If a head gasket blows and there is no water in the oil were does it go. I'm having the same problem with my brothers 95 3.8 she runs good for a while when she reaches m-a
on the temp gauge the fan kicks on and she drops but not all the time the, ford replaced some thing with the fan. I think it was the fan modual or something. i replaced the stat and she was good for a month or so could it have gone that fast.

 

[IndyBlk5.0]

if you dont have water in your oil (like in my case with my blown head gasket) it is more than likely blowing compression from the cylinders into the water jacket of the block. this will let water into your cylinder walls therefore producing a "thick" steam out the tail pipes. Also at the same time as the cylinders go up and down creating compression, some of that compression will be going into your water jacket and pressurizing your system. Your water loss is through your tail pipes via steam. Hope this helped.