94 SL2 Saturn Overheating problems.

Hi guys,

It is summer, and my car is overheating :( Just the other day I noticed that fluid was comming out of the cap. I checked it, and it seems it is broken. I looked into the resevoir and some broken pieces and a spring are laying in the bottom. Okay so I know that has to be replaced today.

But I am concerned that it is not the main source of the problem. For a while now, my saturn has always started to overheat when driving stop and go or just idling at a red light or drive thru. However when I drive at highwayspeeds the temp guage will typically be less than a quater hot. What does that mean? Again when I speed down to stop and go, the temperature will then begin to rise. Luckily the fan always engages and brings the temp down to a bout just little over a quater on the cold side.

Is it the radiator? If so do I have to replace it? is the thermostate, coolant sensor? or what? How do I diagnose this?

Thanks,

-Manuel

Reply to
meloyellowjr
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Sounds like your fan may not be coming on as it should when the engine temperature reaches the trip point. The fan draws air through the radiator to reduce the temperature of the coolant. The fan primarily functions when idling or at low speeds since the air is pushed through the radiator at higher driving speeds (highways, etc.)

Fix the radiator cap first. Then make sure the cooling fan comes on like it should when the engine gets hot. If not, then you can turn on the AC and this should engage the fan immediately. If the fan comes on from the AC, but not otherwise, then it is probably a bad coolant temperature sensor (note that there are two in the early Saturn engines, one that controlled the gauge and the other the cooling fan). If the fan does not turn on with the AC, then it could be a defective fan relay or a bad fan motor or the wiring.

Lastly, if the fan is running, but it still overheats, then you have other problems, possibly a clogged radiator a bad water pump, or a leaky head gasket and will need a pressure test of the system.

Good luck.

Bob

Reply to
Bob Shuman

It sounds like maybe your car is running properly. The temperature has to go up before the fan will come on. The question is how hot is it getting before the fan turns on. My fan turns on at 213=B0 which is normal. The fan turns off at 170=B0. The radiator cap may be a seperate issue.

Look here:

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Reply to
James1549

Thanks for the feedback. I have replaced the cap. I got a stant radiator cap from Kragen and it looks different than the OEM one. But I think it works fine. No more leaks (yet) but the temp still raises at idle.

I looked at those pics, I don't know the exact temp, but the guage needles in your photo positions look very similar to the guage needle of my car. So is it okay for the temperature to start rising when the car is in idle? I can literally see the needle moving if I stare at it. The reason I ask is because other cars I have driven don't seem to do that. The needle just stays in the middle, or a little bit on the cooler side. Is this raising temperature when at idle normal for saturns? BTW yes the fan does kick on when the temp gets too hot, very similar to the pictures on the weblink.

Just curious, hypothetically speaking, what would happen to the temperature guage on the Saturn if the thermostate where either stuck open or closed?

-Manuel

Reply to
meloyellowjr

If your fan is coming on at 213=B0 or according to the pic, then you should be ok. Yes the Saturn temperature gauge is different than most other cars. The reason being that the temperature gauge range is much less than most - meaning your will see more movement when the temperature changes. And that is really a good thing. Most other cars use a gauge with a much wider range causing it hard to see movement with little temperature change.

It is normal for the temp to rise at idle because no air is flowing through the radiator until you begin to drive the car, or the electric fan comes on. I personally would like to see the fan kick on about 201 to 205=B0 but it is controlled by the PCM.

If your thermostat was to stick closed, you would overheat very quickly and boil the coolant out. If it were stuck open, generally the engine won't get up to operating temperature. You will notice that especially in the winter time when you have poor heat temperature in the cab.

Some say that a stuck 'open' thermostat will cause an engine to overheat. For over 30 years in my career working on cars, I have yet to see that.

Good luck, James

Reply to
James1549

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