short of taking it to a shop, how would i know for sure? it's a closed system, no radiator cap, only cap is on the puke tank. took some hits with my temp gun, both hoses and radiator are air temp, gauge reads in the +230 range. t-stat hat and fitting on head reads +200. my guess is the radiator is clogged, and i still can't get the fan to run after replacing fan switch, t stat, and relay. for more history on this: https://www.thirdgen.org/techbb2/sho...hreadid=131652

 

Ede, I had the same freaking problem with my old 94 GA. I re- wired half the system with no results. I gave up and just poped an adjustable fan switch in. I just couldent justify anymore time spent fixing the car but a tech at the dealer told me it could have been caused by a broken ground strap on the engine but I dident find anything and dont see how thats possible. Anyway the car is still running around town I guess that $18 switch did the trick so it just depends on how much a headach is worth.

 

I'm gonna say the gauge sender is bad. Most newer cars don't turn on the fan until 215 to 225F so if your temp gun is only reading 200 on the head where the fan switch is located then its not hot enough for the fan to come on. For what that sender probably costs its worth a shot.

 

yeah i figued on replacing the sender, i have a gauge tester but not the specs on how many ohms it should be. i might test it with the most current info i have. i've considered wireing it direct too, but worried about being too cold in the winter and i doubt if the owner could remember to turn a fan switch on. i'm going to pull the radiator today, the coolant looks nasty, and most of it's new. drexcool has a lot going for it but it sure does mess up a cooling system, i'd never put it in anything i own.

 

Re-post year, make, model, and engine and I will do my best to get you ohm specs for the sender. BTW I have little/no faith in Dex-cool. If it came in the car continue to use it, but otherwise I would not use it in a car that came with green. Don't get Dex-cool on bare skin either, that itching you feel is it eating your skin.

 

it's a 95 2.3 quad 4. my gauge tester is a snap on blue point and i tihnk the referance card that came with it stops in the early 90s. the few times i've used it to check gauges i've just used the old data.

 

The fan won't turn on the with a/c? If the hoses and radiator are air temp then you've either got a clog or the water pump isn't working. Either way I'd replace that sender to make sure you're getting the correct reading on the guage since your gun reads 205 degrees.

I wish I knew what this cooling system looked like.

 

Ede, I have to say a big SORRY. The day after I said I would get you ohm specs my modem decided to clock out. Just got a new one and wanted to apologize. Anyway I could find no listing of specs on Alldata. I still think the sender is bad if its showing overheating but you have no boilover. I was told by a friend that used to work at a Pontiac dealer that it wasn't that uncommom. He also said that they did have a problem with the heads cracking. Look on the back of the head on the drivers side if you have a disappearing coolant issue. He said that Pontiac was covering head replacement under warranty up to 100K miles. Sorry again.