LF Car Help

[darknes]

Ok, I've been having problems with the cooling system on my car. It's a 1999 Olds Cutlass, about 90k miles.
Last year, I had to have the intake gasket replaced since it was leaking very badly (left a trail everywhere I went). They replaced the thermostat as well. Lately, the car has been leaking coolant and overheating again. I found out the leak was from my water pump, and I could see it coming out of the weep hole as well as the bearings were shot. Anyway, the leak is gone, but it still overheats in town.
I narrowed the problem down to the radiator fans. They aren't coming on when the engine gets hot. They do, however, turn on when the A/C is on, so the motors are good. The fuses looked good to me.
Anyone have any suggestions?
I think I'm going to try replacing the coolant temp. sensor tomorrow morning to see if that works.

 

[reefforbrains]

LOL I had dibs on the overheating car issues round here buddy!
anyway, If AC can still overide the cooling system, then I think your on the right track, but leaking from the water pump is never a good sign. Does the pump shriek or make noise?

 

[darknes]

Lol, there's room for the both of us.
Oh, I meant to say that I replaced the water pump, and now the leak is gone, but it's still overheating.

 

[phixer]

And GM wonders how Toyota has taken over.

This might help.
Did you replace the water pump? I think your on the right track looking at the Snsr. Coolant temp sensors are usually pretty cheap so that would be a good place to start. They are easy to check with a multimeter but you must know what the resistance range is supposed to be first. Look at a wiring schematic located in a Mitchell shop manual or one of the Chiltons shop manuals at the library (these are the hardcover thick ones). If you cant locate one see if the dealer will let you look at the factory service manuals wiring diagram. More than likely you can jump the terminals in the sensor plug to bypass the sensor and find out if it's bad.

 

[reefforbrains]

Then temp senson would be next, they are usually cheap and quick so see what happens. You did check or replace relays and fuses as needed correct?

 

[stdreb27]

The coolant sensors on those cars tend to make your car do wierd things. Usually it will thow a code. Is your check engine light on. It will probably say your coolent is not reaching sufficiant temp. Or is too hot. You are right around your 100,000 mile need to flush your coolant. but you probably did that when you changed your water pump.
Is your car a 3.8 liter? My girlfriend had almost the exact same problems on her car at that milage. We ended up doing a waterpump thermostat and the sensor and it has worked for the next 100,000 miles. Out of curiosity, did your intake manifold gasket just break or was it the whole manifold?

 

[darknes]

The car is a 3.1 liter. I did get the waterpump replaced a few days ago, and the coolant was changed with it. As for the gasket, I just had the intake manifold gasket replaced; Apparently GM put a plastic gasket on this engine, and its a real common problem to have problems with it.
The fuses for the fans are good, and I don't know how to check the relays. If the coolant temp. sensor does not fix the problem, I'll just replace those. I bought the sensor today for $12, and I'll replace it first thing in the morning and see if that works.
Thanks.

 

[darknes]

Ok, now I'm stumped. I replaced the Coolant Temperature Sensor, checked all the fuses, and replaced all 3 relays. They fans still will not turn on unless I turn the A/C on.
Anyone have a suggestion on where to look next? Maybe I'm even thinking this all wrong, and the fans aren't supposed to turn on? I let the car get up well above the halfway mark, and they still didn't start.
:help:

 

[stdreb27]

What is the temp at the half way point? Maybe you put the wrong thermostat in, and that is causing the car to overheat. You may have also got a faulty thermostat. You can test it by sticking a thermometer into the radiator and checking the water temp when it opens. I'll go check my girlfriends car tomrorrow and see if the fans kick on when the car starts.

 

[84chris]

Could be an inline fuse, follow your wiring back and look for one. If all else fails just hardwire it to a switch inside your car, and turn it on once your car gets to operating temperature. Atleast then you will know that the fans are on and if it still overheats then you probably have a radiator problem.

 

[usmc6026]

you might possibly be airbound as well those cars have 1 or more bleeder screws on them any problems call my shop mon.@ 631-676-4401 ask for tony.