'95 ATX suddenly overheat

[kumba]

Long story short. Yesterday I drove a mile (literally) down to the store, half way through drive back I could hear/feel the coolant popping in the block, looked at gauge, and it was almost pegged. Pulled over and parked it for 2 hours, then came back drove it rest of the way home where it got up to the N in about a 1/2 to 1/3 mile very easy drive. On the drive back I put the defroster on high-fan max heat but it never blew anything but ambient-temp air.

When I got it home I popped the hood, saw no smoke/steam, heard no sizzling, and there still appeared to be some fluid in the reservoir. This morning I go out, it cranks over fine, starts right up, no new or interesting sounding noises. I immediately turn it off, pop the radiator cap, it takes about 1-quart of water and is backing up the filler neck. I went ahead and filled the reservoir up to the mark and then drove it around the block some. It again in less then 1/2 mile began to over-heat and I shut it down and parked it. Again no sizzle or steam or the like and again no heat from the defroster.

So my question is where should I be looking? Bad T-Stat? Bad Water Pump? I am inclined to think it's a water pump because I have no heat inside the car.

All help is much appreciated. Most of my wrenching experience comes from a 5.0 T-Bird and 4.9L F150. The SHO is quite a different beast from those two.

Thanks.

 

[TopGunnYFZ]

It's leaking from somewhere, and the temp gauge is fluctuating and no heat because its low on coolant, you probably have an air bubble in the system. I would fill up the radiator and squeeze the upper hose a few times and check the level again it should go down, keep repeating those steps until the level doesn't go down anymore. Then start the car with the defrost on high and 90* leave the cap off and let it get to temp to open the T-stat it should suck the level down, and you can add more coolant until it flows out of the neck with warm coolant. You should then put the cap back on and let it build pressure to see where its leaking from. Check the passenger side floor for dampness as-well.

I don't trust the workings of the res. bottle because ive had my radiator be a gallon low and the bottle was still full?

 

[sperold]

Thermostat.
Get it out of there before it really lets you down.
Get if from Ford (autolite or motorcraft or something like that) and install with the jiggle valve up. Do your best to flood the motor with coolant so the thermostat is virtually sitting in it when you install it.

 

[kumba]

That was it

That is it. The thermostat went from stuck open to stuck close. Car seems much happier now. Thanks.