[Engine] temp gauge goes up and down

[Rui Peters]

hy everybody


My little van has a suspected head gasket temp, gauge goes up and down while driving but never boils over. I'm no mechanic i did a head gasket test and it's showing negative  so any sugestion and help from someone please!!! Many thanks

[geoff]

.... up and from what and too ???

[robbiec97]

Mines just started doing this after replacing head gasket, any suggestions would be great! going up and down between 90 & 100

[saskak]

what engine is that? Petrol/Diesel?

[robbiec97]

dw8b 1.9d 8valve mate

[oilyrag]

Might be worth bleeding the system and also the thermostat itself might be sticking?

[Carl.1]

Just going by what we did years ago when we had no money ....

If the temp rises and when hot then noticably drops but then stays even your thermostat is working ok.
If it stays hot with a little or no drop your thermostat may be sticking and either needs replacing or throwing away. Years ago we threw them out as it was cheaper!
The car will not complain. I was told this may cause an issue in the winter, just mevr discovered what as the car still ran fine just the heater took a lot longer to get going.

You can whip the thermostat out, and boil it up in a pan of water. If it is ok you will see it open when hot.

Unless cars have moved on and all the above no longer applies! Who knows?

[asdf]

What about coolant temperature sensor?

[RattyCortina]

I believe that taking the 'stat out can have the opposite effect as the coolant circulates too quickly and doesn't transfer heat from the engine as effectively...??

[geoff]

Don't remove and leave out the thermostat please as you will likely compromise cooling at the cylinder head causing local overheating and probable head gasket failure.

No further info from Rui ?? anyway it is possible that all is well and normal.

Robbie, it gets confusing with folks jumping onto someone elses Topic always better to start on specific to yourself.
Robbie I'd be looking at bleeding the system ( there are specific bleed points ) can you tell us if the temp problem was present before the head gasket failure or is it since then ?