2000 Volvo S70 overheating

DawnK31 · Post by **DawnK31** » 21 Aug 2014, 10:49

Hi Everyone,

I have a 2000 Volvo S70 that is overheating. I have had the sensor, water pump, and thermostat replaced but it still says it is overheating. The mechanic thinks it is an electrical problem and said it could be anywhere. Does anyone have any thoughts or recommendations? This is my primary car and I am not in the financial position to replace it.

Thanks,
DW

Post by **abscate** » 21 Aug 2014, 11:50

Dawn...we need to figure out if it really is overheating or not. Does it smell hot and is coolant boiling out of the reservoir ( plastic tank on right side of car as you look back, on your left )

Don't open the container while the car is Hot as it will spew coolant.

Is the temp gauge up high with the red light flashing?

Post by **regent** » 21 Aug 2014, 12:14

DawnK31 wrote: ...I have had the sensor, water pump, and thermostat replaced...

Was the ECT sensor replaced with an OEM part?
Does the radiator fan come on when it should?

DawnK31 · Post by **DawnK31** » 21 Aug 2014, 12:18

The water is not bubbling, the temp gauge immediately goes into the red as soon as your start the car. I think that the ECT sensor was replaced with the thermostat and the radiator fan seems to be coming on more than necessary. The person who looked at it said the fan is running too much and it will eventually drain the battery.

Post by **abscate** » 21 Aug 2014, 14:07

Good.

Obvious problem in the ECT, wiring, or gauge as opposed to engine.

You need to measure the resistance of the ECT when cold with a volt ohm meter and compare to a chart which I will try to find and link here.

We will ignore that this was replaced, it's likely a bad part. The resistance test is definitive.

Post by **jreed** » 22 Aug 2014, 05:41

CN90 wrote up a nice guide here that explains the symptoms of a bad ECT and how to replace it:
https://www.matthewsvolvosite.com/forums ... hp?t=52203