Coolant Temp. Problem -- Too Cold

[Fuzz]

Alright!! I finally got the 92 EX on the road, it is running like a beauty, just some minor wiring glitches (like the Rad. Fans not turning on when the ignition is on).

I'm having a problem keeping the coolant temperature at normal operating levels (200F). If I let the car idle, it will sky-rocket to 260F, and the fans never kick on unless the ignition is off... but if I DRIVE the car, especially with our -10F weather, even when it is only 30F outside.. the coolant temp drops all the way below 100F. (I have an aftermarket temp guage).

I am thinking it might be the Therm. is stuck open, and that maybe the radiator is a little bit too large for the car. After driving it for a while, and the engine is hot, if I sit at a light long enough, I will see it slowly climb above 100.

What would be a nice quicky solution for this. I am thinking of maybe getting a piece of plexi or something and blocking part of the rad. What would you guys think??

I never thought I would have a problem with under-heating of a car... it's always over-heating!!

Kev

[ExplodingCake]

Leaks are the main cause probably. Thermostat malfunction is also a pain in the butt. Check for leaks on hoses. Check the thermostat also. Fans should kick in when engine comes to a point its getting hotter.

[cali-racer]

try replacing the thermo....doesnt cost that much and its easy to replace

[d112crzy]

if your fans dont turn on while the car is on and only when its off, then one of your ect sensor plugs might be mixed with some other plug. make sure 2 green ones are connected to the tstat housing.

theres a gray one that is the exact same plug, same wires. just its for a different sensor.

I had that same problem.

[Turbo Dave]

Alright!! I finally got the 92 EX on the road, it is running like a beauty, just some minor wiring glitches (like the Rad. Fans not turning on when the ignition is on).

I'm having a problem keeping the coolant temperature at normal operating levels (200F). If I let the car idle, it will sky-rocket to 260F, and the fans never kick on unless the ignition is off... but if I DRIVE the car, especially with our -10F weather, even when it is only 30F outside.. the coolant temp drops all the way below 100F. (I have an aftermarket temp guage).

I am thinking it might be the Therm. is stuck open, and that maybe the radiator is a little bit too large for the car. After driving it for a while, and the engine is hot, if I sit at a light long enough, I will see it slowly climb above 100.

What would be a nice quicky solution for this. I am thinking of maybe getting a piece of plexi or something and blocking part of the rad. What would you guys think??

I never thought I would have a problem with under-heating of a car... it's always over-heating!!

Kev

if its getting cold it wont be the thermostat
ur fan relay is bad. a large radiater wouldnt do that, when ur drivng anything above 40mph the fan doesnt need to be on, so naturally in below freezing temperatures going 40mph with a fan on will make itr run at 100 degrees.

[SteveB]

Thermostat is stuck open. Replace with a OEM piece.

[SteveB]

if its getting cold it wont be the thermostat
ur fan relay is bad. a large radiater wouldnt do that, when ur drivng anything above 40mph the fan doesnt need to be on, so naturally in below freezing temperatures going 40mph with a fan on will make itr run at 100 degrees.

Temp senders are in the block, whose temp is regulated by the thermostat.

The fans only regulate the temp of the rad.

[Fuzz]

The Thermo is a Mechanical Device, it doesn't work off the sensors.

I know the plugs are un-plugged, the ECT Sensor for the Vehicle Gauge is unplugged, actually the sensor is out, I have aftermarket sensors in the vehicle. (Thats how I know the Coolant is running way too cold).

It could be that the ECT and the Fan Switch got mixed up, but I will check that... But if they are mixed, why does the Fan turn on when off??

I will replace the Thermo today if I can and try...I just figured, since I can't do anything over the night, just to post and let people brain storm.

Thanks for the Advice.

Kev

[SteveB]

The Thermo is a Mechanical Device, it doesn't work off the sensors.

Correct. But the temp of the senders is governed by the 'stat.

[asleepz]

Make a "T" out of some plumbing parts and hook the sensors back up and replace the thermostat.

[BlackMagicCB7]

I have the same exact problem you have word for word.... My fans only click on when the car is off. If I let it run still for a while like in slow traffic or a drive thru, the temp will redline. My solution was to turn on the AC and use the single AC fan to cool the radiator. I don't think its your thermostat, I replaced mine and its not the issue. I think its a matter of replacing the fan switch.

Bump.....I have same exact problem. Need some advice too....

[Fuzz]

I was going to put some T Fitting on a little bit later, but it is hard finding the proper ones around here.

My problem isn't so much the fans coming on... I can always make a bypass switch for that, or the coolant temperature spiking... My problem is that the coolant temperature never gets to NORMAL, unless the can is sitting for a very very long time (and then the fans turn on... the Fan Switch sensor is still hooked up).

It has to be either the Thermo is stuck open, so the coolant is always going through the radiator, hence while driving, the coolant is always cold... (I take off the cap after driving and it is like warm milk).

That or like I said, it could be possible the radiator is too big (Isn't it suppost to be a 1/2 radiator, 1/2 AC 'Cooler' ??).

Kev

[SteveB]

I was going to put some T Fitting on a little bit later, but it is hard finding the proper ones around here.

My problem isn't so much the fans coming on... I can always make a bypass switch for that, or the coolant temperature spiking... My problem is that the coolant temperature never gets to NORMAL, unless the can is sitting for a very very long time (and then the fans turn on... the Fan Switch sensor is still hooked up).

It has to be either the Thermo is stuck open, so the coolant is always going through the radiator, hence while driving, the coolant is always cold... (I take off the cap after driving and it is like warm milk).

That or like I said, it could be possible the radiator is too big (Isn't it suppost to be a 1/2 radiator, 1/2 AC 'Cooler' ??).

Kev

Size of the rad is doesn't matter....you could use Lake Superior as a heat dump, as long as the thermostat is working correctly.