temperature gauge

[kalim]

Hi everyone.hope someone can help with this.my 08 vectra sri was of the road for 3 months before i bought it and repaired it(side damage cat d).its been on the road now for 2 weeks and was fine at first.since 3 days ago the temperature gauge has been acting weird.ive read some prevous threads and seen that these symptoms are linked to the thermostat being faulty.the heaters work fine after about 10-15 minutes of been started but if ime driving on the motorway the temp gauge goes down to zero but the heaters still work.get of the motorway and park up the temp goes back up to 90.I know that whilst driving cold air hits the engine but surely the temp needle shouldnt go down all the way.its not that bad when driving around town but sometimes if i put the heaters on the needle will slowly start going down but not all the time.my last car an astra didnt have a temp gauge so didnt worry bout it but looking at this i know somethings not right.any advice apreciated.

[scotstrucker]

Hi I would get the thermostat replaced. Is your car a petrol or diesel. The 1.8 petrol engine thermostat is easily replaced as I changed the one on my old 1.8 very easily. The temp when it was replaced was just under the 90 mark no matter the road or outside temp and the heaters were roasting. I sadly now have a 1.9 cdti 150 which is pish and am getting the thermostat replaced on that under warranty.

[carpet]

As scotstrucker, I would look at the thermostate as motorway driving blast lots of cold air around the engine and if the thermo is stuck open this will drag the temperature down, but allows it to raise when you slow down in traffic.

[robert_dale]

Defo a thermostat change, I had the same problem, new thermostat fixed it!

[scotstrucker]

Does anyone here have a 1.9cdti 150?

[kalim]

thanks for the advice.you guys were all correct,it was the thermostat.i took it to vauxhall motorbodies and they replaced it free.a point to note is that they said if you have a damage repaired car it doesnt affect the mechanical warranty as long as the fault isnt caused by the actual damage.result