"Coolant temp is lower than thermostat temp" messa

Post by **ssforcey** » 29 Jan 2008, 17:42

I've gotten this as a message through a diagnostics test? Any idea what it could mean?

Thanks so much,
Sharon

Post by **MadeInJapan** » 29 Jan 2008, 18:24

That's a new one on me...what year and what model?
I may be wrong but logically what would make sense is that your thermostat is stuck...which means you need a new thermostat, or your coolant temperature sensor is malfunctioning. I'll try to research this and post back.

Post by **ssforcey** » 29 Jan 2008, 20:20

Thanks so much for your quick reply. It's a 2002 V70. Someone else mentioned a new thermostat also.

Thanks again,
Sharon

sony2000 · Post by **sony2000** » 30 Jan 2008, 16:33

Most likely the thermostat is stucking open and not letting the engine warm up to the operating temperature. Its also a cheaper part than the sensor.

Post by **ssforcey** » 30 Jan 2008, 17:49

Should I stop driving the car right now? I'm thinking I'm okay. Also should I go ahead and replace both of them while I'm in there?

Thanks
Sharon

Post by **MadeInJapan** » 30 Jan 2008, 20:30

On the earlier cars we would do both at once. Although the car has changed from the earlier models in a lot of ways, the basics haven't, including the location of the sensor and thermostat. If you replace one, you open things up that make replacing the other very easy. Just because of this, I would do both if I was doing one....and I think it's good preventative maintenance. Neither part are real expensive either, so that's good news!

However, before doing any of this, I would go to an autozone and let them reset your code with their scan tool (free at most auto parts stores) and see if this message comes back. If it doesn't, it could have just been a fluke (sometimes Volvo's do strange things). If it comes back, then you'll know for sure what's up.

Driving your car if the thermostat is stuck open really isn't going to hurt things for the short run (may cause you to not feel very warm in your car, and poor mileage and a few other things that can cause problems over time) like driving it with the thermostat closed shut which will over-heat your car and could cause engine damage. Best bet is, either way to take care of this issue as soon as possible.

Post by **JRL** » 30 Jan 2008, 21:25

MadeInJapan wrote:
Driving your car if the thermostat is stuck open really isn't going to hurt things for the short run (may cause you to not feel very warm in your car, and poor mileage and a few other things that can cause problems over time) like driving it with the thermostat closed shut which will over-heat your car and could cause engine damage. Best bet is, either way to take care of this issue as soon as possible.

Not quite true. If a thermostat is stuck open, especially in the winter, the engine will run VERY cold and very rich, neither very good for an engine.
A cold engine means cooler oil temp, BAD for an engine