Coolant temp gauge - Audi A4 - Pat L
Advice needed please.

The coolant temp gauge on my Audi A4 has started to return to the minimum (60) setting for a few minutes and then returning to the usual mid setting (90). Then a few mins klater will repeat this. No apparent reason, I\'m usually cruising at 65-70.

It never goes above 90 but should it be going up and down between 60 and 90 as it is at the moment.

Oil temp gauge stays constant.

Is there a sender fault?
Could it be connected to the fact that the aircon (climate control) is being pushed harder in the hot weather?

Car has 2 weeks of warranty left and I would welcome opinions.


Coolant temp gauge - Audi A4 - Malcolm_L
This is definitely a fault, what speed is this occuring at?
Could be sender fault, however a multitude of other faults, e.g. Dashboard connection, thermostat sticking open.

If the car is still under warranty register the fault now with your service garage (by fax or email).

Is your coolant level ok?

Coolant temp gauge - Audi A4 - Pat L
Thanks, Malcolm.

Yes coolant level is ok. From cold the car takes a good 3-4 miles to get to operating temp (90)(always has done), and it usually stays there. However, in last three weeks I've noticed this yo-yoing of the needle between 90 and 60. Seems to be getting more frequent.

I did mention it (in passing really) to the service manager at my Audi dealer a couple of weeks ago when I was having an oil change, and he mumbled something about a lazy thermostat! What's that?

Anyway, I'll contact them to register the fault.

Coolant temp gauge - Audi A4 - Malcolm_L
I suppose if your engine didn't start that would be lazy too!

What a load of carp!

Worth getting checked soon as if there is a coolant problem rather than a thermostat problem - not the time of year to find out!

best of luck
Coolant temp gauge - Audi A4 - sean
Hi Pat,

There is no connection between your engine cooling system and your cabin cooling system. Gauge temp and climate control, yes?

The gauge reading is determined by the instrument, the sender or the wiring (plus the voltage stabiliser).

You could have air in the cooling system, but unlikely.

Yes, there is a fault. See a VAG dealer and it will be fixed.
Coolant temp gauge - Audi A4 - Aprilia
Once had a very similar problem on a Mercedes - it was the thermostat slowly failing.
Audi A4 temp gauge - UPDATE - Pat L
Just a quick update on the little problem I posted a couple of weeks ago.

Dealt with very efficiently by dealer under warranty (just in time!) - they replaced the thermostat and temperature sensor and have cured the problem. Full marks.

Had an A2 courtesy car for a day. Quite impressed; handles nicely, well built, looks good (despite 'advertising' all over it!), though 1.4 petrol engine was a bit weedy. Not my sort of car but I liked it nevertheless. Certainly drew a lot of attention with the 6" writing all over it extolling its aluminium construction, 80 mpg economy etc!

The car is out of warranty from Sunday, and as this is the only problem I've had I just hope there's nothing big lurking round the corner!

Audi A4 temp gauge - UPDATE - daveyjp
I'd challenge anyone to get 80 mpg out of an A2 in general use - best I've ever had is 58 from the 1.4 diesel. The 1.2 Diesel (not available in UK) may achieve nearer 80.

Did you have a look at the service hatch on the bonnet? Best invention ever and I can't see why its not been adopted by other manufacturers. Check and top up the oil and top up the washer bottle easily without lifting the bonnet and no excuses about not finding the dipstick amongst everything else thats under the bonnet!
Audi A4 temp gauge - UPDATE - Stephen Tune Up (BTON)
Common fault on audis and is always cured by replacing sensor on all the audis that I have come across with that fault.
Audi A4 temp gauge - UPDATE - DL
Thanks for the feedback (I mean it!) as I have an Audi, which is performing well at the moment!

Added to the 'fault memory bank' for future recall!
Coolant temp gauge - Audi A4 - jud
i had a temperature sensor fault, this did not affect the gauge read out but did allow the car to rev up occasionally on start up. Audi found a fault code for this, i now have Vagcom to view the codes my self.

Value my car