When the fans finally do kick on does the temp gauge go back down? Before changing the radiator, I would advise having someone with a scan tool plug in and read what temp the car's computer believes that you are running.

I dealt with a '97 Grand Prix that has a temp gauge that climbs to 260, no fans kick on and here I found that the computer reads 163 (which, given I could touch the intake and t-stat housing with my bare hands, makes sense).

It's obvious the fans are working, the question is, why are they NOT coming one when you expect them too. By the fact they kick on at what appears to be very LATE timing, changing the radiator is NOT going to fix that timing. You appear to have something else going on.

 

I was thinking the same thing, but even though fluid went through it just fine it is still running between half and red, about 230 degrees, with both fans running all the time. The fans cannot cool it off regardless of circumstances.

I'm thinking that maybe just some parts of the radiator are clogged, so only a little bit of the fluid is getting cooled off as it goes through.

I even ran the car with the thermostat removed and it still runs extremely hot. Reached about 250 degrees to be exact, according to the temp gauge of course.

 

New symptom: when its hot both upper and lower cooling lines are burning hot.

Lower one should be much cooler. Makes me think that fluids are not cooling at all as they pass through the radiator.

 

Keep in mind, even at proper operating temp, those hose can be HOT. But, to be burning hot sounds a bit odd.

I would not JUMP to changing the radiator (there it more then just the radiator that could be choked up). Get some cooling flush (Prestone sells it in a small bottle), follow their directions and flush the system. That stuff is made to help dislodge gunk in the system.

Also, it would not hurt to get the read from the car's computer and and make sure it lines up with what the guage is reading.

 

You are driving an old car. The electrical connections are also old. Go pull the fan relays and clean the plug ins. They are sealed so you can't do the contacts. But you can "wrap" on it.

I ran my 95 in through the shop and the kid there.....probably 38.... thought it was water pump, thermostat, hoses, etc and wanted to replace my radiator next. I noticed the fans were not coming on unless the AC was on. So I went to the relay panel and pounded on it with my fist. The fan came on and the temp went down. Bad electrical connection.

 

Hi guys Im new. Bakerman/Anyone HELP!!. I have this issue now in my 99 Monte LS. Fans wouldnt come on unless the the A/C was on. Now that has changed and they are not comming on until the engine is almost 230+ degrees. Pulled the 5-pin relay (pass side) and jumped the relay connections with a wire the rt fan comes on immediately when I alternate between speeds, different jumper connection, fan runs accodingly. Can believe it is a bad connection as if it was the jumper wire wouldnt work at all, my logical thinking.

Have checked 30 Amp fuse, its good, and replaced all 3 fan relays anyway, 2-4pins and the 5-pin, new thermostat today, bled the radiator to get air out....will do more tonight as I just gave it a short run. Fans still not working properly and car only runs correct temp on open hwy when there is enough air flow to cool fluid. Could I still have a bad connection even though the jumper wire works fine?? When the car is turned off after heating up the upper rad hose compresses as it cools so I dont think there is an air leak. Stumped on this please help!!