Running temp fluctuation.

[jm-baker]

Recently i noticed the temp would suddenly drop from 90 on the dial to around 80 - 85, noticed it most when on the motorway driving at a constant speed....

Instantly thought thermostat !

Tonight i got the temp up on disp #49 on the Air-con diagnostic display. For most of my journey the temp didnt go above 80 deg (dial a fraction under 90), so still thinking thermostat...... untill i pulled up and it crept upto 90 on the diagnostic disp, but kept going to 102 untill the fan kicked in and bought it back down to around 90 ish, though all the time the dial was bang on 90, even tho it apparently hit 102....

a) I thought the fan should come in way before 102. so could this just be a faulty temp sender reading HI?, or even a faulty fan switch?

b) Why does it stay down at 80 when drivng, either thermostat is sticking or the temp sender is reading LOW?

Any ideas please.

Might just change both the Thermostat and Temp Sender.!?

Cheers

James

 

[jm-baker]

The more i think about it, i think it is the thermostat.

I would imagine a fan switch would come in somewhere around 100 ??

Therfore the sender is correct.

 

[jimbobery]

Hi. I had a temperature fluctuation problem which turned out to be thermostat. Now it goes up to 90 and never moves. When I was looking into this I think I read that the fan does kick in around 100 and then switches off around 95.

Its not too expensive to change both thermostat and temp sender. Thermostat is a bit of a pain as one of the bolts is a bit tricky to get at but with the right tools its not too bad. There is a fair few post about thermostat change on here and a guide.
There is also a guide for the temp sender on http://www.wak-tt.com/ (I think)

 

[Clach]

well done soame probs on mine. Although it has not fluctuated for a while now!!

 

[jm-baker]

Replaced the thermostat today, all seems to be sorted now! Will keep an eye on it for a while tho!

James

 

[1animal1]

where is the thermostat on these? picking up the sender tomorrow....

 

[1animal1]

actually cancel that, ive just searched the previous posts and found a fitting guide....what an **** of a job!!

 

[themanthatcan]

actually cancel that, ive just searched the previous posts and found a fitting guide....what an **** of a job!!

Certainly looks it if you don't have the right tools. I got mine changed at the same time as my clutch as it looked a bit too fiddly for my liking!

 

[jm-baker]

Not the easiest of jobs, prob took me an hour in total. Not too hard just fiddly. I removed the wires from the alternator to give more access too.

The most important tool is a 3/8" set of extentions and a UJ adaptor to get to the bottom bolt!!

 

[1animal1]

my worst worry is emptying the coolant.... replaced on my first car and didnt prime it correctly, almost ended up over heating..... last time i touch a coolant system

apart from the sender unit which is a doddle to fit