Hi all,

The temperature needle on my Octavia MK1 has started to behave erratically. Every now and then it just shoots up to the top (130) and I get the red indicator and beep.

I have read other posts that blame the sender but I have changed it about a year ago (for a green one), and the timing belt was done professionally around the same time so the cooling pump is new as well. I can also hold my hand on the radiator and the expansion vessel which are definitely hot but not impossible to touch even when the temp needs says otherwise.

This seems to only happen when driving. If I'm idling for an extended period of time the needle settles at 90 so I'm assuming the thermostat is fine. The driver side radiator fan starts periodically once I've reached 90 degrees (there are 2 fans on the radiator, I assume the passenger side one is for cabin heating?).

The fan creates a fair bit of vibration when it's running which led me to think the car is detecting an issue with the fan. But at idle, when the fan runs, the needle behaves normally and I get no alarm.

Another strange thing but probably unrelated is there is a component marked "Sagem" almost constantly clicking on top of the charcoal vapour filer.

Any leads is greatly appreciated, as well as advice regarding whether I can drive the car or not. I have hell of a lot on my plate until Wednesday so I'd like to delay a trip to the garage until then.

Thank you for reading!

Edited 7 March7 Mar by mrfry
spelling mistake

Update: I noticed that coolant was weeping from the temp sender slot. I had kept the old sender which I had only changed because of a "manufacturer control" error code but was otherwise working fine.

I noticed the old o'ring is thicker than the one provided with the spare so I assume I bought a subpar spare. So far no alarm...

May have been a wiring connection issue. Check the wiring back from the sender to make sure its not shorting somewhere.

Alasdair

Thanks Alasdair, yeah I did try and wiggle all the accessible parts of the loom but no luck in triggering the fault that way. I have managed to trigger it by bleeping the throttle at idle which shakes the engine a bit so I agree with you that a bad wire is a strong contender... I have only driven the car from where it's parked to where I can work on it, and so far so good. Electrical issues can be very elusive...

Edited 8 March8 Mar by mrfry

Reckon if its going to max it may be a short somewhere. Your being very polite by saying electrical issues are very elusive. I have many other phrases. Hope its an obvious one

Alasdair

Female dogs and hemorroids might get a mention eventually but I try to save those for offline ;)