Hi,

I've just bought a 2002 V40, my very first Volvo!

Since the trip to my work and back allows me to drive at constant speed for quit some time it's probably needless to say I'm a fond user of the cruise control.

However, when travelling on cruise control I notice that the engine temperature is fluctating. Initially the engine gets up to normal working temperature but then the gauge starts to fluctuate. Usually the guage moves somewhere between the normal operating temperature and about half of that, but sometimes the needle drops way down only to recover quickly. Since I assume that the acual engine temperature does not fluctuate that easily I'm suspecting a broken temperature sensor or thermostat.

Suggestions anyone?

Thanks!

you are correct, the t-stat has failed in the open position.

Replace before it gets too cold.
--
'88 240, '92 745, '98 v70 John, Tampa Bay

Hmm, I suspected something like that.

However, the strange thing is that de temperature is not fluctuating all the time and, lucky for me, the temperature is about right most of the time (needle hoovering at the 'straight-up' position). Is this a sign that the t-stat is about to give up completely of can there also be something else causing the fluctuations (or at least the appearance of fluctuations)?

Thx.

Dekam

If the 2002 is similar to the 2000 S40 there is a temperature sensor screwed into the thermoatat housing. Since the temperature is fluctuating so quickly on the gauge it might be the connection on the sensor or the sensor itself.

Look to see if there is a connector in the tstat housing and go from there.

Also since youre there, changing the tstat probably wouldn't be a bad idea either.

Miker