Temp gauge dont move much

[melvin]

I have noticed my temp gauge stays at 70 for a long time, if I drive about 25 miles it may go up a wee bit maybe to 75 and then it could drop again. I have heat in the car but I dont know if its as warm as it should be. I was going to replace thermostat but was wondering if it could be anything else.

Its a cdti 150, 80k.

Thanks for any advice.

[hairy31]

I have noticed my temp gauge stays at 70 for a long time, if I drive about 25 miles it may go up a wee bit maybe to 75 and then it could drop again. I have heat in the car but I dont know if its as warm as it should be. I was going to replace thermostat but was wondering if it could be anything else.

Its a cdti 150, 80k.

Thanks for any advice.

there all like this mate..........there are loads of posts on here about it!

[mozzer99]

The latest thermostat is modified and improved.
These engines are so fuel efficient that they give out little heat compared to a petrol.
The heater is capable of pulling more heat out of the engine than it is producing at slow speeds.
If at motorway speeds the gauge should go to 85c no matter what setting the heater is on.
With a new thermostat my 150 CDTI takes 5 miles at motorway speeds to warm up. If in queuing traffic with heater on full it never reaches 85c.

However in the summer these figures are halved.

From what you say I'd change the thermostat at it should go higher than 75c on a long (fast?) run.

[barney490]

Tis true, the heater is capable of pulling more heat out of the engine than it is producing at slow speeds. In summer on my usual journey to and from work, the gauge will reach 85 just as i get to work, its only 6 miles. The same journey in this weather with the heater on and the gauge never moves, all perfectly normal for the Vectra. If however, as has already been stated, the gauge doesn't hit 85 at motorway speeds, then suspect the thermostat jammed open.

[melvin]

Thankx for replies guys. I havent really been doing any motorway speeds as I dont be on any motorways just A and B roads, average speed has probably around 50 mph with the frost and all.

[jrh1]

there all like this mate..........there are loads of posts on here about it!

So does that make it right.Did they leave the factory like that?

[diesel dog]

Lots of these engines are thrashed up and down autobahns on a daily basis. If you look at some of the vids on youtube you will find that they have no problem getting all the way up to 90 and above on the temp guage!

But it does seem as though VX, or whomever, intended the latest 1.9 engines to run as cool as possible. I guess that's what happens when an engine that was originally intended for no more than 100bhp or so gets tuned up a bit.

[husky]

Did my thermostat on my CDTi 150 yesterday as the gauge never moved unless your were sat in traffic , half an hour later sorted and now sits at 85 round town and toasty warm inside the car and the total sum of £37.95

[Paulrushton]

I drove 13 miles in temps as low as -11 and the gauge never moved. Car was toast and warm though. I'm leaving mine.

[Das]

Sorry I dont agree with this theory that the diesel engine runs too cool to make the gauge work properly. Thermostats open and close as the temp rises and falls. If the temp doesn't get high enough, think its either 86 or 92 degrees C, then the thermostat would not open and the gauge will rise and only show actual engine temp, and the only cooling will be through the small heater matrix if the heater blower is on. Next time you've been driving for a while and the temp gauge is flat on the floor feel the radiator bottom hose, if its cold the thermostat will be closed and the diesels run cool theory will be true, if its hot then the stat must be open.