Overheating 1997 850 wagon

tcapp · Post by **tcapp** » 15 Feb 2007, 16:58

Car ran hot. After sitting for about 2 hours gage still red hot! Good level of coolant in the resivior but no pressure on the hoses. Anyone know whats going on?

Post by **MadeInJapan** » 15 Feb 2007, 17:07

Most likely bad thermostat...cheap and easy to replace. Turbo or non-turbo? A bit more information would be helpful..for instance what was going on to over-heat the car...what repairs were done recently, etc.

tcapp · Post by **tcapp** » 15 Feb 2007, 18:08

car is used for magazine deliveries. ran from about 9:00 till 2:00 then started to run hot. Valve job about 7000 miles ago.

tcapp · Post by **tcapp** » 15 Feb 2007, 18:27

Its now about 8:30 and the car has sat since about 2:00. Iwent to go start it and just turned the key to the on position when the gauge went to the top and the fan came on. The engine is ice cold. When I turned the key back off the fan continued to run for a few minutes. It's never done that before. Even during the summer southern heat, if the fan was running with the car on, it stopped when the car was turned off.

Post by **akitawagon** » 15 Feb 2007, 19:21

As MIJ mentioned earlier, you most likely need to replace the thermostat, as that is "usually" the cause of the dash temperature display to be reading incorrectly.

While you're doing the thermostat, it would probably be good replace the coolant temperature sensor at the same time while the coolant is drained out.

You need to give us more details on what model car you have as there may be other factors involved.

greasefingerss · Post by **greasefingerss** » 15 Feb 2007, 19:31

That would have to be the coolant temperature sensor. If you have an ohm meter unplug the sensor and measure the resistance across the CTS. It should be several thousand ohms at ambient temperature. An engine at operating temperature should read low in resistance (something like a couple hundred ohms) Yours appears to be grounding out.

tcapp · Post by **tcapp** » 15 Feb 2007, 19:43

First off, thanks for the quick reply's. This is a 1997 glt wagon with a little under 130000 miles.
Where is the coolant temperture sensor and how much coolant to drain out?
Thanks again

Post by **MadeInJapan** » 15 Feb 2007, 20:49

The temp sensor is at the end (bottomish) of the thermostat housing to the left side of the engine (when facing the car with hood up). The thermostat housing has a hose running to it from the over-flow tank. Hope this helps. Drain or pump out all of the coolant in the tank, then clamp the large hose from the radiator to the thermostat housing and you'll have very little coolant to contend with. Putting an old towel down in that area will help. Other than this, you'll need at least a 5 inch long T40 torx socket (trust me) to clear the fuel lines to undo the thermostat housing screws. You can buy both the thermostat and the sensor from www.fcpgroton.com There are two thermostats. General rule is if you have a turbo car, or live in a hot temp. area, get the lower temperature one. If you drive a non-turbo car or live up north, where temps are generally cold (Canada for instance) then buy the higher temp. thermostat. Good luck and let us know how things are going. Took all but 15 minutes to change my thermostat out when I did mine. I didn't have to do the sensor.

tcapp · Post by **tcapp** » 16 Feb 2007, 10:51

Got the thermostat, but where do I find the long torx bit? I only found a set of 5 sizes and that was $90. Need to get running this weekend. Any help is appreciated.

greasefingerss · Post by **greasefingerss** » 16 Feb 2007, 11:32

When I got my Volvo I decided to buy a 7-piece Torx-bit socket set for $ 29 at AutoZone. (T15, T20, T25, T30, T40, T45, &T50) That way I can use them with my ratchet and any combination of extensions. I do not care much for Torx allen-keys, if that