Thermostat Replacement Advice

[callahanoffroad]

Does anyone have a diagram for a non-ecc climate system? I did a cursory search online and only saw ecc diagrams.

This what you're looking for?

MCC Manual

Yes!

Exactly! Thanks!

[brunocerous]

Thanks to all the great advice. When refreshing the coolant system in my '98 V70 a few months ago, I stripped the T40 bolt due to not applying enough downward force. (I had done my other '00 V70 correctly, so it was probably a bit of overconfidence on my part.)

I ended up removing the fuel rail, drilling the bolt and using a screw extractor. In place of the Torx bolts, I used 10mm bolts from a water pump. Then I swapped the thermostat, temperature sensor and upper radiator hose.

1998 Volvo V70 thermostat with a stripped Torx bolt

1998 Volvo V70 thermostat housing bolt extraction

[mecheng]

I think thermostats get lazy or don’t seal well. My 850 would take a long time to get to operating temp, when I replaced the OEM wahler thermostat it looked fine. It wasn’t broken and was closed. I replaced it with a Mahle and it warms up much quicker. No codes were thrown

[Sommerfeldt]

I think thermostats get lazy or don’t seal well.

That's exactly what happens. The multitude of heating and cooling cycles does result in "lazy" thermostat operation due to a kind of "metal fatigue". It is also the reason for them mostly failing in the open position though, so the bad goes with the good, I guess.

- S