Volvo 480 Club Europe

Can the Thermostat get stuck?

Every day the car gets overheated. I sometimes have to stop and let It cool down a couple of times, when going to work because the warning flashes "STOP" as the water temp rises to 115 degrees celsius.

Sometimes the temperature suddenly drops to 80, (finally opens?) and after that the thermostat works as its supposed to. 80-90 degrees.

But after cooling down when Im working, its the same behaviour on the way home again.

I had the thermostat replaced at a shop, since the old one failed, and after replacing, the probloms occured.

Please help!!!!

is it the right thermostat?
Is the cooling water circuit ok? Or do you have any blockage?

Really dont know. Did not experience any problems before having the termo changed. Its supposed to be the 89 degrees celsius, but maybe the garage installed a different..

sounds very much like a sticking thermostat . can be checked easily enough but you would need to remove it.

I would change the thermostat it is an easy job.

I'm with Jim

what is your OIL temperature saying? typically it will lag behind the water temp and on a LONG run it does get up towards 100C ,

try this BEFORE removal of stat

is there water in the radiator, did they bleed it at the wee red plug between the block and bulk-head, open slowly when cold and water should 'just' weep out

it is only three bolts and if been replaced already then the bolts should come out NO problem.

or try removal of stat and run a couple of days with 'open to radiator' approach aand check results, it could be a dicky sender but TBH if run OK for a while his is unlikely.

Thanks guys! Unfortunatly I haven got it sorted yet. I returned the car to the garage, but they dont find anything wrong. It wont overheat, they say. But still, they changed the thermostat.. At least they claim.

Took a "longer" trip and had to stop because it got overheated again. Its funny how it gets stuck when the engine is cold. When it comes loose, it works great as long as it doesnt cool down. Could it be they have mounted thermostat the wrong way, so the engine have to overheat before the water reaches 89 degrees on the outside / wrong side of the thermostat at first warm up, so to speak?

Just a thought

I took it to a garage because I didnt want any troubles...

the thermostat can only mounted in one way! So thats not the mistake ...
Did have the sensor at the fan cooler the right worths? But it only manage the fan cooler, not the KI.

Well.. cooling fan sensor is not in any way the problem. It sits in the radiator, and how do you figure it would have anything with the stat not opening? Even if it would, the hot water could not reach it, because.. ..the stat is not opening so the water cant cirulate.

The garage will change the stat for the third time this friday, and this time to a volvo original! Hope that does the trick!

Finally!

They installed a Volvo original thermostat and the problem vanished. No more overheating! It opens an closes perfectly, and works between 80-83 degrees.

Stay the f-word away from after market junk stats!

The garage is a big swedish franchaise, "Mekonomen" and have their own parts, so to speak. But after replacing it twice with the same problems, they finally tried the original spare.