Temperature guage fault.

Jake Blight · 25-01-16, 12:01 PM

Flushed the radiator and replaced anything that needed replacing. Now the temperature gauge keeps shooting up even when cold. Any thoughts? Engine runs fine, pipes warm nicely, no apparent cold spots or air locks. I think its the temperature sensor/ sender (brass and white thing pictured). Not keen on forking out almost £30 just on a hunch.. Quattro Corner has a sensor on standby for me but I thought I would ask you lot first to see if anyone has had something similar happen.

No leaks, it's not overheating and drives fine.. I am stumped.

mikes2 · 25-01-16, 01:05 PM

what happens if you disconnect - I'm guessing it will fall to zero

Gauge going off the scale is usually achieved by earthing the signal wire for the gauge.

You can check for a short on the 2 wires and also across the terminals on the sender.

Duffy3074 · 25-01-16, 01:25 PM

I thought the one for the gauge was the one on the underside of that elbow?

Mellis46 · 25-01-16, 02:54 PM

The single one underneath (on the kv at least) is the coolant temperature sensor, plenty of fun and games it causes too with lack of cold start or funny idle speed when it begins to mis-behave...!

Jake Blight · 25-01-16, 04:50 PM

Food for thought there.. Thanks for the heads up.. Alas can't look at it for another few days so will have to fret about it until then. i so get 'tetchy' when silly stuff goes wrong..

sinbin5t · 25-01-16, 04:52 PM

[quote=Jake Blight;39828 Alas can't look at it for another few days so will have to fret about it until then. i so get 'tetchy' when silly stuff goes wrong..

[/QUOTE]

Yep know that feeling well

M4rkp · 25-01-16, 05:45 PM

out of interest - what engine code are you?

If it keeps shooting up randomly, then disconnect the sender, if it carries on shooting up then you have a short ( to ground) in your harness - if it stays at the bottom, you have a sender issue.

I recently had the reverse of your problem - no temp gauge at all - changed sender - twice - still no gauge.......it turned out that i had lost electrical continuity between the block and the water outlet!

Mark

Colin Aitchison · 25-01-16, 06:19 PM

On my 1987 B2 Coupe GT the one on top with two terminals is for the engine temp gauge the one on the bottom with one wire is for the ISV, if you would like I could go and measure the resistance across the terminals of the top sender when cold and see if you get close to the same if not a similar ohms reading I would say it is the sender.

Colin Aitchison · 25-01-16, 06:29 PM

just had a look on www.partsbase.org the part number for my coupe 2.2 GT is 049919501B copy and paste this in to ebay and there are two under £9. This part is fitted to many Audi/VW engines, also if you remove the two pin plug from the sender dose the gauge drop to cold, if not it is a wiring problem, if it dose it is the sender. Hope this helps.

Jake Blight · 25-01-16, 06:52 PM

Quote:

Originally Posted by M4rkp

out of interest - what engine code are you?

If it keeps shooting up randomly, then disconnect the sender, if it carries on shooting up then you have a short ( to ground) in your harness - if it stays at the bottom, you have a sender issue. I recently had the reverse of your problem - no temp gauge at all - changed sender - twice - still no gauge.......it turned out that i had lost electrical continuity between the block and the water outlet!

Mark

My cq is using the KV engine. Thanks for the above.. useful.

25-01-16, 01:05 PM	#2
mikes2 4 ring whore! Classic Audi Club Member Join Date: Nov 2007 Location: Polmont Posts: 2,617	what happens if you disconnect - I'm guessing it will fall to zero Gauge going off the scale is usually achieved by earthing the signal wire for the gauge. You can check for a short on the 2 wires and also across the terminals on the sender. __________________ 1991 90 quattro 20v sport 1991 90 quattro

25-01-16, 01:25 PM	#3
Duffy3074 4 ring whore! Classic Audi Club Member Join Date: Aug 2015 Location: Dalgety Bay, Fife Posts: 2,167	I thought the one for the gauge was the one on the underside of that elbow?

25-01-16, 02:54 PM	#4
Mellis46 Aero Advocate Classic Audi Club Member Join Date: Aug 2014 Location: Lancashire Posts: 1,455	The single one underneath (on the kv at least) is the coolant temperature sensor, plenty of fun and games it causes too with lack of cold start or funny idle speed when it begins to mis-behave...!

25-01-16, 04:50 PM	#5
Jake Blight Grown up member Classic Audi Club Member Join Date: Sep 2015 Location: Cornwall, near England Posts: 881	Food for thought there.. Thanks for the heads up.. Alas can't look at it for another few days so will have to fret about it until then. i so get 'tetchy' when silly stuff goes wrong..

25-01-16, 04:52 PM	#6
sinbin5t 4 ring whore! Classic Audi Club Member Join Date: Jan 2010 Location: Where a spike points skywards Posts: 12,960	[quote=Jake Blight;39828 Alas can't look at it for another few days so will have to fret about it until then. i so get 'tetchy' when silly stuff goes wrong.. [/QUOTE] Yep know that feeling well

25-01-16, 05:45 PM	#7
M4rkp Grown up member Classic Audi Club Member Join Date: Feb 2013 Location: Sometimes Roberttown - sometimes Surrey Posts: 194	out of interest - what engine code are you? If it keeps shooting up randomly, then disconnect the sender, if it carries on shooting up then you have a short ( to ground) in your harness - if it stays at the bottom, you have a sender issue. I recently had the reverse of your problem - no temp gauge at all - changed sender - twice - still no gauge.......it turned out that i had lost electrical continuity between the block and the water outlet! Mark

25-01-16, 06:19 PM	#8
Colin Aitchison Senior Member Classic Audi Club Member Join Date: Dec 2013 Location: Back home in Tillicoultry Posts: 1,343	On my 1987 B2 Coupe GT the one on top with two terminals is for the engine temp gauge the one on the bottom with one wire is for the ISV, if you would like I could go and measure the resistance across the terminals of the top sender when cold and see if you get close to the same if not a similar ohms reading I would say it is the sender.

25-01-16, 06:29 PM	#9
Colin Aitchison Senior Member Classic Audi Club Member Join Date: Dec 2013 Location: Back home in Tillicoultry Posts: 1,343	just had a look on www.partsbase.org the part number for my coupe 2.2 GT is 049919501B copy and paste this in to ebay and there are two under £9. This part is fitted to many Audi/VW engines, also if you remove the two pin plug from the sender dose the gauge drop to cold, if not it is a wiring problem, if it dose it is the sender. Hope this helps.