This sound like a thermostat going?

[dan_b]

Since having the aircon regassed a few months ago, I've been running the aircon all the time - to keep the system lubricated, and also to see if it leaks again (so far, so good).
However, I have since noticed that my water temps have been a bit low. I first put this down to the aircon cooling fan running all the time - when I switched aircon off, it invariably would rise to the 90 position.

Now, this doesn't seem to happen anymore, and on a decent drive, water temp basically seems to be around 70, even with the aircon off (hard to tell as the grad lines don't make sense to me!).

Eg a drive back from Cheltenham on Saturday night along the A40 then down the M40 at fairly interesting velocity, with aircon off, don't think the temp actually got up to 90 the whole way back.

Does this sound like the thermostat?
Is this a major problem?
Is it tricky to replace?

Thanks guys

[blu_s2]

Dan, don't know if it helps.... but having spoken to a coupleof others off-line the general consensus is only take the guage as very rough guide.

Logging data with vag-com my car sits consistently at 87.5 degrees under *normal* driving. My guage shows 1-2 marks below 90 degrees.

I was worried my stat was on the way out but the vag-com logged data seems to put the blame on the guage.

[The Spanish]

My ABY coupe had a similar problem.
On highways water temperature used to fall halfway between the 50 and the 90 degrees marks, driving around the city it went up to around 1 or 2 gradients over 90.
Changed the thermostat recently and now it only drops to about one gradient bellow 90 no matter how fast I am going and no matter how cold is it. (Around 4 degrees and 130 mph actually)
Hope this helps

Cheers.

[martinjs]

Does it take longer for your heater to blow hot air, since changing mine guage sits 2-3 marks below 90 when cruising,rises to 90 when in traffic, get warm air through after 2 miles or so from startup

[The Spanish]

I haven't notice any major difference in the heater time to blow hot air.

I will try to pay more notice to this.

Before changing the thermostat and with a really cold weather outside (-3 ºC, FOR MADRID THIS IS VERY COLD) it did take two miles to get hot air. A lot of time to freeze inside the car in my opinion.

Cheers

[dan_b]

I guess I could just be being a bit paranoid - it has got colder here in the UK in the last few weeks, it may just be that? However, what I get does sound like what The Spanish has described.

If it is the thermo, is there a bigger problem waiting to happen, should I go out and change it?

[jameswkr]

If your thermostat is not allowing the engine to get up to the right temp it will be hurting your MPG and not helping the oil do its job. Dont forget to replace the two small hoses under the thermostat ( see other threads ). I was only able to access it by removing the PS pump, but other listers disagree.

[andre]

Hi there

Going from my experience on this subject, I think the important thing to worry about is the CHANGE in behaviour. My car used to always sit at two ticks below 90 on the highway and two ticks over in traffic. I found the second speed of the cooling fan was not working and once that was fixed it sat at 90 in traffic and two ticks below on the road. It then started to run slightly warmer on the open road which I put down to summer and the increase in ambient temp. Then the other day in traffic the thermostat says cheers and died CLOSED !! Thank goodness for the overtemp warning alarm.

It's now been changed and consistantly sits as three ticks below 90 on the highway and at 90 in traffic.

As before, be wary of a deviation from the normal behaviour rather than how it compares to other cars.

Andre