More temperature gauge trouble...

[TomB 0]

Sorry, but I didn't want to highjack another thread :) I know my gauge is a little dodgy, as it doesn't read the water temp at all, until the car starts getting hot (usually when coming back into town after a run). When it starts to work, the warning light starts to flash, and keeps doing so even once the temp is back down.

The coolant level is fine, the fans are working, but I'd like to get it fixed just in case there ever IS a problem with the temp. Can anyone suggest where to start looking? Wiring? Behind the instrument cluster?

Any advice greatly appreciated.

Cheers,

Tom

[davidwort 0]

Sorry, but I didn't want to highjack another thread :) I know my gauge is a little dodgy, as it doesn't read the water temp at all, until the car starts getting hot (usually when coming back into town after a run). When it starts to work, the warning light starts to flash, and keeps doing so even once the temp is back down.

The coolant level is fine, the fans are working, but I'd like to get it fixed just in case there ever IS a problem with the temp. Can anyone suggest where to start looking? Wiring? Behind the instrument cluster?

Any advice greatly appreciated.

Cheers,

Tom

 

temp senders on the side of the head first I'd say, Haynes passat manual tells you which is which, can't remember off the top of my head I think there are 3 small ones one for oil temp (MFA) one for ECU, you could pull them one at a time to check which ones which. also check earth straps from head to bulkhead.

 

David.

[Henny 0]

The gauge water temp sender is the black on in the black plastic flange on the front of the head (where the blue on is)... They're about £10 from GSF/Euro and take about 2 minutes to change when the engine's cold... Don't forget to buy a seal too! ;)

[TomB 0]

Cheers gents, that sounds like a good place to start... :)

[Henny 0]

just thinking... get the engine warm and turn it off... disconnect the blue and black temp senders and swap the connectors over... turn on the ignition and see if your temp gauge works again. (DON'T start the car though!)

 

If you gauge works then, it's definately the black temp sender that's dead.

If your gauge still doesn't work, it's either a wiring fault, or the gauge is damaged...

 

Personally, I reckon you've got a loose connector on the back of the clocks 'cos the flashing light is set off by low coolant level, not by temp, so you've got 2 different sensors which are acting up, so it's more likely to be the gauge/common wiring which is at fault... ;)

[TomB 0]

Well that answers my question of what to do with some of the 3 days of A/L I have left :D Cheers Henny,

[coullstar 0]

Tom this happened to me for the first few days after I bought the car but just went away. I did notice that the water temp gauge did take a while to move but that was only after driving the silver one. I initially thought the silver one was overheating till I realised it was normal.

Hope all is well.

[TomB 0]

coullstar, all is very well, in fact this is the only minor niggle I've had! Like I say it's a minor problem, and one of those things that it would be nice to do, but not essential... It's still running beautifully, and I look forward to getting in the drivers seat every time :) How's your valver coping with the commute?

Cheers,

Tom

[coullstar 0]

Broke down this morning due to immobiliser probs. £65 a week in fuel is kinda killing my Christmas spirit.

[nephilim 0]

Silly question - are the blue / black senders on the front of the block to the rhs of the dipstick? I can see two correctly coloured connectors here and there's a yellow one to the left of them and a blank to it's left?

 

My temperature gauge is also non-functional (hardly moves at all) so I thought I would also try to diagnose the problem.

[Kevin Bacon 5]

Silly question - are the blue / black senders on the front of the block to the rhs of the dipstick? I can see two correctly coloured connectors here and there's a yellow one to the left of them and a blank to it's left?

 

Yep, there's a row of three....Yellow, Blue, Black.

 

My temperature gauge is also non-functional (hardly moves at all) so I thought I would also try to diagnose the problem.

 

Assuming the engine isn't undercooling, then it will be the yellow sender or the guage itself. The guages in the VR6 instrument cluster are all available seperately. The rev counter module is about £25 as a guide, so the temp guage module should be around the same or less.

[nephilim 0]

Cheers for that. I will try to take a look at the yellow sender tomorrow if that's the one connected to the temp gauge on the dash.

 

The temperature gauge does rise a little but only when I'm stuck in traffic. The oil temperature works fine (app. 90-100 deg on a normal run) and the oil pressure seems consistent with the oil temp so I don't think the engines running cool.

 

I will see if they have the part in Camberley Auto Factors. Does it just pull out of the block?

[Kevin Bacon 5]

Yeah I went through a thermostat housing and stat change for a fellow member as his guage did exactly as yours did and we suspected the engine was undercooling. But after all that, the guage stayed the same!

 

I'm not sure how far he has progressed it but I suspected it was either the yellow sender or the guage.

 

Yeah the sender just pulls out of the housing.... if you're quick enough, you can pull the old out and stick the new one in without losing too much coolant, but relieve the system pressure first by taking the expansion cap off. Put some oil around the new senders seal first aswell to ease fitting it.

 

Try the sender first. It's a 4 pin item and is now yellow/green I believe.