95 Volvo 850 GLT thermostat issue

BlackyChan91 · Post by **BlackyChan91** » 26 Dec 2015, 20:49

Hi again guys... I resolved the starting issue in my other post just needed a new battery... Now I'm having another issue... I'll be driving along and all of a sudden the temp guage shoots up to half then back down to a quarter after 5-10 mins... I'm thinking thermostat but maybe I'm wrong... Any ideas lads???

Steve

95 850 GLT 2.4 vrooooooom
88 MR2 bone stock
84 Mustang 3.9
Toyota Camry XLE
94 Honda Civic EJ
06 Civic LX
04 VW Jetta 2.0
91 Prelude Si 4ws

Post by **cn90** » 26 Dec 2015, 21:44

- Tstat: use Wahler $18 or so. Search forum for the tricks on how to undo the stubborn Torx bolts.
- ECT: use Volvo or SWF brand, around $50. I wrote the DIY in forum.

Post by **erikv11** » 26 Dec 2015, 23:24

More likely the problem is the ECT sensor = Engine Coolant Temp sensor, and most likely is an ECT connection issue. First thing to do is to check the connector where it gets crudded up with coolant over the years, and sometimes falls apart. If the connections appear good then probably need to replace the ECT, but replace both that and the stat, as alluded to by cn90.

Post by **abscate** » 27 Dec 2015, 06:18

There are good sets of resistance measurements in threads on this Board and the VRD as well

BlackyChan91 · Post by **BlackyChan91** » 27 Dec 2015, 09:21

I'll look into both and reply asap... Should I be worried about possible overheating?

Post by **erikv11** » 27 Dec 2015, 09:44

I would be pretty careful about using the car, yes. As you have probably surmised, there is a very low chance that the temp gauge is showing actual temperature, due to some kind of erratic thermostat opening and closing or another clog in the cooling system.