Suddenly overheating after good temps all day

foyburgher · 06:37 PM

I cursed myself by writing an email to the P.O. (who took great care of my 1983 944 NA) telling him what a great first year I've had driving the car with no problems! And then I spent all yesterday telling the lady who was with me about how great the car has been and what a good deal it was and how practical it always is...

So then I overheat suddenly after driving with good temperatures all day long, and no history of overheating. I got flat-bedded home, then took out the thermostat and tested it and it's working fine. I've left it out for now.

Reconnected the hoses, refilled the water, and started bleeding the system, but here's the weird part. The radiator isn't heating up. I get water squirting out of the bleed screw immediately after starting the car, so I don't think it's the water pump, right? The water pump was replaced and only has 15k miles on it. (The thermo-fan switch was replaced a few months ago too, but it's not getting hot anyway, so you know...)

Now I'm thinking it's the radiator. Could the radiator suddenly develop a clog? The upper radiator hose gets really hot, but the bottom one stays cold. And after peeing water out of the bleed screw, I start to get all steam coming out and then the temp gauge starts to creep into the red zone so I shut off the car.

I'll keep searching the forums and keep trying to sort this out on my own, but any help, questions, suggestions, would be greatly appreciated!

Matt

CJFusco · CJFusco's Garage

Are the fans kicking on? I had a situation once where my fans weren't kicking on, and it turned out that one of the connectors had come unplugged off the thermoswitch

foyburgher · 06-19-2006, 06:15 PM

Thermoswitch is ok and I replaced it 6 months ago.

I think my 2 clues are:
a) The overheating problem happened suddenly, after no overheating problems for 1 year, and driving about 50 miles with temps in the middle of the gauge right before it happened.
b) the upper rad. hose is hot, but the radiator is cold. It doesn't even heat up enough to kick on the fans. But the engine starts to overheat...

Eldorado · 06-19-2006, 06:53 PM

perhaps a blockage in the rad?

Brando · Brando's Garage

^ my first guess as well.

Coolant = hot and radiator = cold -> point to blockage.

foyburgher · 06-20-2006, 05:27 AM

Thanks guys. I'd love to find out that I have a clogged/cracked radiator. I'll get the upper rad. hose off today (stupid bracket-to-air box bolt is spinning...need more tools) and then I'm going to get creative with the garden hose.

SoCal Driver · SoCal Driver's Garage

Take the air box bracket off at the three studs on the top of the radiator cross bar. Leave the bracket and the AFS on the air box.

foyburgher · 07-05-2006, 11:30 AM

Thanks SoCal, it's little tips like that that help us newbies.

The problem turned out to be that my waterpump had totally seized up after only around 10,000 miles. Insanity. I bought all the tools and replaced the waterpump and timing belt. I learned so much about my 944 by doing it and I recommend doing the work yourself to anyone thinking about it.