Okay guys, I have been battling an overheating problem for a while now, and I keep telling myself I am going to take it to a shop, but I never do due to lack of funds....

Anyhow, I have a very inconsistent problem. Sometimes it will go 100 miles without overheating. Sometimes it will overheat when I am going down the road and then cool back down when I stop (and vice-versa <sp>). It used to only do it if I held it consistently at 80 mph or so and then exited the insterstate. But it wouldn't start until I stopped and then took off again. Fans run all the time, and I doubt the problem is something simple like that.

Now...the other night I took it out and about 25 miles later I was heading back to my house and by the time I got there it started to overheat. I pulled it into the garage, with the gauge at about 240*, and turned it off. I cranked it up a few times to see if it would cool down (it's worked before) but never did. I then twisted the radiator cap just enough for the loud sound and coolant resevoir to start bubbling. I guess I let all the pressure out of the sytem or whatever. After that I cranked it up and it cooled right back down to 180* and stayed there, even idling inside my garage.

Since then I drove it three times about 15 miles each and it never overheated. Then, tonight I drove it about 30 miles without any problems. I stopped for gas and cleaned my windshield, and cranked it back up, and it started to creep up to 210* and rising. I stabbed the gas pedal fast and let off(also has worked before), and about 3 seconds later the gauge stopped then headed back in the other direction until under 180*. It stayed like this until I got to my driveway (long/dirt/have to go slow). It started creeping up again and stabbing the throttle didn't help. I pulled it back into the garage, now at about 240* and noticed the coolant in the resevoir boiling. However, the sides of the radiator were like room temperature, and the radiator cap was even cooler (it felt like it hadn't even been run yet). Is this normal? The radiator hose to the thermostat was hot, but not hot enough to burn me, like it seems like it would be if my car was overheating. BTW I am running a 50/50 mix and have tried more water already with no luck. I also backflushed the system and tried 2 different thermostats.

So...sorry this was so long, I was just hoping someone who understands more about the cooling system could try to explain to me why all of these wierd things are going on and if they have any suggestions...

ANY help is much appreciated.
Thanks-
Jonathan

 

hmmmm that sounds really odd...have you checked your waterpump to see if it's weeping? The only thing i can imagine is an intermitant water pump.....say it was pumping too little, the car begins to run hotter...the resivoir fills up and boils over, the pump stops pumping alltogether, the air cools the radiator off very quickly but the engine temp now skyrockets just before you stop.....maybe. Just a guess. Also i would check the timing. I doubt it's your problem but i would check.

Engine at 240 and resivoir boiling, but radiator cold, thats very odd.

 

Sorry but what does a "weeping" waterpump do???

 

Also, it's funny you say something about timing. I found out last week the guy that owned it before me set the timing at 0*, instead of the factory 6*. I adjusted it, but it didn't help my overheating problem, in fact, it didn't even make my car run any better....

 

Is there any way to test a water pump while it is on the car? I didn't enjoy changing this thing out about a year and a half ago, but if anyone else thinks it might be the waterpump, I might get a new one before I take it to the shop....

 

have u replaced the cap yet?

 

Yeah, that was the first thing I did. Unless the one I bought was defective.....
Oh yeah, does it matter what lb cap I get?? The one I bought said 16 lb.