Temp gauge/sender?

[dest]

My temp gauge never stays up at the normal 90.
If I start the car and let it idle, the guage will go up to 90 and sit there all day with the fan kicking in to keep it in check.
If I then start driving it drops back down to pretty much nothing showing on the gauge, then get back into town/traffic stop start driving and it will start to go back up to 90 again.
The heater works fine.
Ive been told it could be the sender on the back of the block (ABY) is that this part?

https://sslrelay.com/s74326199.oneandoneshop.co.uk/sess/utn;jsessionid=15479728f15747e/shopdata/index.shopscript?main_url=0010_Audi%2F0080_S2%2B%3D2B%2BRS2%2F0030_Electrical%2Fproduct_details.shopscript%3Farticle%3D0120_3%25252Bpin%25252Btemp%25252Bsender%25252B%25253D28034919369C%25253D29

[S2central.net]

Ignore the sender at back of engine for this - that is just for the ECU.

The temp display in the cluster comes from the MFTS in the water rail.

You should also check the voltage regulator on the cluster - if its wobbly you will get strange readings on the water temperature and fuel gauges.

I have some updates to s2central.net on this subject in the works. I'll see if I can get my finger out over the next or so and get that polished off.

Paul

[dest]

The fuel gauge works fine.
My main thought is the thermostat not working?
At a guess, it is warming up enough to get the gauge moving when idling, but once on the move with air cooling it the gauge is staying low.
I really hope its not the stat cause I dont want to try changing it

[Jas11n]

Exactly the same as what mine was like before changing the stat (also my bro's 95 ABY was like this when he bought it, stat changed and it was sorted).
I lived with it for a while purely because I feared as you do now, that it was a nightmare to sort, but a split hose under the water rail (the common little ****** to fail) forced me into doing it.

I really hope its not the stat cause I dont want to try changing it

It's not that big of a job, honest. Get at it from the front by moving the PAS pump out of the way. Ignore posts saying you'll have to faff around remove aux rad, no you don't and I even had air-con condensor in the way too.
Use the time you are in there to replace that little ****** of a hose I mention above cos it'll most definately go at some point (it's only a couple of quid from vagparts) and to give the whole water system a good flush, including the now available to flush "throughly" block.
Stepped run through with pictures >>> here

Start to finish (including me indulging in a bit of OCD) was about 2.5 hours.

My temp gauge now sits a nats nut below 90 and stays there while driving, whatever the temp. Sit in traffic and it'll creep to a tad over 90 when the fan then cuts in.
Oh, G12+ (plus) for the coolant as you'll not know what in there now, G12+ mixes with G11 and G12 (which seriously piss each other off)

HTH's
Jas..

[Pirvu Eugen]

Is the thermostat.
my one was the same.
Changed the stat and no problems.

[dest]

As I thought then
Thanks for the guide, I dont really feel confident in doing it myself though
Anyone fancy earning afew quid?

[S2central.net]

Agreed this sounds like thermostat also. As Jas11n says - wrap it up with a few other tiresome jobs when you get that far in.

[Animal Mother]

As I thought then
Thanks for the guide, I dont really feel confident in doing it myself though
Anyone fancy earning afew quid?

Defo the stat, mine did the same.

Not a big jub either, just a little fidly. Plus you get the satisfaction of not having to pay anybody.

[Jas11n]

As I thought then
Thanks for the guide, I dont really feel confident in doing it myself though
Anyone fancy earning afew quid?

Shame you are so far away, I'd have done it for nowt.

Jas..

[dest]

Am I right in thinking it will cause it to run rich cause the ecu thinks its running cold all the time?

I dont mind travelling abit to get it done, Co. Durham might be abit too far though!

[Jas11n]

Am I right in thinking it will cause it to run rich cause the ecu thinks its running cold all the time?

You'd have thought so, and by rights yes, but I've noticed no difference between before and after in mpg figures. [shrug]

[Animal Mother]

Am I right in thinking it will cause it to run rich cause the ecu thinks its running cold all the time?

Spot on.
When mine needed changing it was kicking my MPGs ****! Will be on "choke" for want of a better word.

[S2central.net]

Yep - when water is cold, you get more fuel for enrichment and more advance.

Can't say I miss using a 'choke' right enough. Last time I had to do that was on the Astra 1.6SR of my student days - had a flaky GM Varajet carb with automatic choke that was temperamental so I put on a Weber 32/34 DMTL carb with a manual choke to solve that problem. Ahh the old days.

[redz]

I have the same issue will have to take a sunday out to get it done as well as the Mark H mod ..

[S2central.net]

I removed that weber carb before I sold that car - glad I did - only had a few thousand miles through it and these puppies can make decent money on eBay. Bonus - just gotta find it now

Paul