temp guage drift

[antelope]

Hi
My temperature guage on my '91 2.3 carlsson drifts from about one third up to two thirds up and back again, regularly, on about a sixty second cycle when I'm driving. What could be causing this?

Cheers
Antelope. Well, Dave actually.

[Simon]

Welcome Dave...

Sticky thermostat?

Simon.

[antelope]

Hi Simon
Last time I saw you was at northampton couple of years ago when I had just bought a 900 cab. Yes, thought the thermostat and have bought one...just can't bring myself to fit it in this brass monkey weather. poste just in case anyone had any other insights.

Dave

[Simon]

Dave,

I'm know I'm going to embarrass myself here as I've got a memory like a sieve but it was either a dark blue or grey 900 Convertible, right?

Simon.

[antelope]

Yep. grey. Mutts nutts or so I thought. Turned out to be a cut and shut job. I lost over 7 grand putting it right and went through a court case which I lost even though the judge admitted I was the big loser in the right. Had no proof though. Anyway, at least the car ended up a proper one. Had to take the whole front end off, windscreen forward, an rebuild. I did enjoy it whilst I had it though.

d

[Simon]

What an absolute nightmare! Sorry to hear that. Hope you have more luck with the Carlsson.

Simon.

[Elmo91]

I have the same problem with my 9k. I replaced the thermostat with a lower temp., but the engine temp. still fluctuates quite a bit.

Since the coolant is pretty old, I am going to try to flush the the radiator to see if that helps.

If there are any other known culprits to this problem I am open to suggestions.

Thanks,

Trey

[antelope]

:! Apparently another possibility is a dodgy temperature sender. Unfortunately they cost over 30 quid and I haven't splashed out yet..thought I'd replace the thermostat first. I'm told that, if i change the sender then i must, under no circumstances, do so with the ignition on.

[antelope]

Because the temperature sender also sends data to the Engine Management Unit, when the temp is percieved as being low, the mixture is made richer...so fuel consumption goes up...and the bores are repeatedly washed with excess fuel and so the engine wears out! Seem to be answering my own question here!

d

[BillJ]

Originally Posted by antelope

Seem to be answering my own question here!

I reckon it's time to get on with it and let us know whether it cured the problem :wink:

I've never done this myself, but I believe that if you keep the new one to hand while you unscrew the old one, then swap them over quite quickly, you should lose very little coolant. If you've changed the thermostat and drained and refilled the coolant in the process, then you won't be wanting to do it all again.

[antelope]

Glad you said that as the prospect of draining the system was one of my main reasons for being lazy! I'll do it this wednesday and let you know if it worked.

Cheers
Dave
1991 9000 Carlsson 2.3 manual

[BillJ]

Just make sure the coolant reservoir cap is fitted before you start (dunno why it wouldn't be, but since you're messing with the cooling system...), otherwise the stuff will gush out