major cooling problem

Alright I have had this cooling problem for some time now. With the radiator and the resevoir full. You can drive around for oh about 30 minutes normal or hard driving. Doesn’t matter. If you stop at a stop sign or red light the engine creeps over to hot relatively fast. Once you start moving again it drops back down to just above halfway. I am 100% the fan works cause it is always running when I shut the car off. Right now it currently doesn’t have a thermostat( I know I need to put it back in) But it had the problem before I took it out and it still has it now. One thing this is interesting today. While I was driving I passed a car and when I mashed the gas. When the revs got way up there my little resevoir spewed coolant out all over the windshiled( I have the hood off. The only thing that I can think of is that either the water pumps fins might be so corroded that it just won’t pump effeciently or the damn radiator is crap. The resevoir is VERY dirty so the radiator may be gunked up. Any suggestions?

Check to see if the fans are running while the car is ON. There are two separate sensors that turn the fan on. One turns the fan on when you’re at a certain temp and the engine is running. The other turns the fan on when you’re at a different temp and the car is OFF.

Basically with each one you have a sensor which sends a signal to a relay, then the relay sends the signal to the fan.

First check to see that the fans do indeed turn on when the engine is running. If they aren’t, then make sure both fans are working. If both fans work, then test the appropriate relays. If both relays are working, then test the sensors.

I know that both fans work, but I didn’t know they both ran off different sensors when the car is on and off. So I would rather just wire them both up to run all the time when the car is on. I don’t want a switch. I just want them to come on when I turn the car on. Anybody got any ideas on how I could do this. I am sure someone has already done that, if so then just drop the link here if you can. Thanks

Its not that one fan runs off of one sensor and the other fan off the other sensor. Its that different sensors tell the fans to turn on at different times.

Why wire it up so the fans run all the time? The system wasn’t designed to work that way, so why do you want it to work that way? Its probably more likely that its a relay malfunction than an actual malfunction with one of the sensors. And testing and replacing the relays is super easy.

You could just wire 'em up to run all the time, but I’m not going to suggest it.

Ok I am not 100% but I assume that the bigger fan is the cooling fan. The smaller fan for the a/c. Well the a/c fan comes on when I turn it on. It also comes on when I shut the car off, if the car is to hot. However the big fan never came on at all. Not when the car was running, not when it was off, not when it was HOTHOT or cold. Could this alone cause the car to overheat. It would explain why it cools off when its moving and heating up when I stop. IF this fan has a bad relay then which one is it.

i have exactly the same promblem… i changed my head gasket ang water pump. and still the same thing. now my car overheated and the car wont start. pls helpp…

ok I tried to check the relay with no success. I am not positive on how to do those. I will get it checked out. However, as a temporary fix. I installed a fuse and a switch to turn the fan on when I want it on. THAT WAS SUCCESSFULL and the fan runs. SO I started out on a little lets see if it will run hot journey. I drove it pretty hard but not ragging it out or nothing. It stayed below halfway the entire time. That was about for 20 miles or so, then I decided to turn on the A/C. The a/c on for about five minutes(good and cold) I look down to my surprise and the gauge has creeped over to HOT. I cut it off and it slowly starts coming back down to where it was. What gives? That makes absolutely no since to me. When I get back home, the main fan still on from my switch. Cut the car off and the little fan kicks on to I guess cool the engine off. Any help or suggestions would be appreciated.


you might need to get a new radiator, some of that gunk that your talking about might of clogged some of the rows in the radiator. at highways speeds their is enough airflow to the whole radiator to cool off the hot coolant, but at a stop light when only the fans are on, they dont pull air through the whole radiator. try a new radiator or get it cleaned out and see what that does. i would replace the radiator now before its too late and you blow the head gasket.oh and put in a new thermostat when you do get the radiator fixed.

So if my main cooling fan is not working and my car is overheating where under the hood i need to be looking at? i checked my fuses and their fine. and my A/c has no charge in the system.

First, run a jumper wire from the battery to the fan to make sure that it is still operational. Then I suggest pulling the connector off of your Engine Coolant Temp Switch (ECTS), and jumping the connector to see if it provides the necessary ground to your fan, it should come on. I actually crossed the wires off my ECTS so my fan runs whenever the car is on, but I live in year-round hot weather, so no harm done.

Actually I did some more troubleshooting and it looks like my temp gauge is giving me false readings , so the cooling fan does spin up after 10-15 mins, I looked in the repair manual and read that the gauge wiring may have a short in the line or the ECTS is bad. Anyone know how to go about this?