A3 Tdi 1.9

[rfisher]

What temperature should this run at?

Used to read 90 deg C.

Then the gauge started to go up and down randomly.

Had the temperature sender replaced and now it reads 75 deg C.

[S2AVANT]

Ours both run at 90, once they have warmed up.

[sleep envy]

both the 2.0 and 1.9 TDI's run bang on at 90

[rfisher]

Thanks.

Just a bit concerned that the grease monkeys have either used the wrong sender unit or bust the thermostat during replacement of the temp sender.

Great!

[purdy84]

The needle points straight up....if thats any help

[Martin_Bpool]

Thermostat staying open?

How old is the car?

[rfisher]

Car is 6 years old.

Thinking it's an air-lock now as it got up to 90 on a city run. Normally spends its time on motorways.

[Slyjoe]

Tagging onto this, same question but a 1.8 petrol - runs at around 70 deg c - unless I'm driving hard then around 90 deg c - is this normal?

[MElliottUK]

mines 90 all the time, GT TDI

[jeffers999]

thermostat is stuck open mate i had the same prob with my s3 used to be on 90 deg all the time, then started creeping down when driving ..

[rfisher]

OK so where can I buy a thermostat?

Either around Leeds area or online with sensible delivery charge.

Thanks.

[S2AVANT]

German Swedish and French
or EuroCarparts

[philip walker]

If the fault happened when the temp sender was changed. I would look at that to be the problem.

Remove the sender and check the part number on the one fitted. There are a few options to fit.

[rfisher]

philip walker said:

If the fault happened when the temp sender was changed. I would look at that to be the problem.

Remove the sender and check the part number on the one fitted. There are a few options to fit.

Well that's what's interesting.

Old sender - showed 90 when warm. Took a long time to get there. Would drop below 90 and then go back up. Occasionally would not get to 90 at all but stay at around 70ish.

New sender - gets up to 75-80 slowly. Stays there.

So - maybe both sender and thermostat were bust and now it's just the thermostat that's bust?

[philip walker]

The fault occured when the temp sender was changed? The I would think this may be to blame. I doubt the thermostat has also failed. Red Herring me thinks.

A few simple checks.
1. Check the flow in the engine when warm. If the thermostat is stuck open the lower radiator hoses will be hot. The heater temp may also be reduced.
2. Plug the car into a decent scanner or Vag Com and in the "measure blocks" of data you will see the engine temp displayed.