Temperature drop off at motorway cruising speeds

[stu_b]

Noticed today whilst cruising on the motorway at normal fast lane speeds that the temperature would drop from 90 to around 70-60 and then back to 90 if i slowed to slow lane speeds. I do a lot of motorway miles and not noticed it do this before it was only 1*c at the time 5 this morning but shouldnt really affect it

Its had a thermostat about 4 months ago but was wondering if anything it could just be down to increased airflow? or something to do with temp sender unit?

 

[s3 Hoggy]

I'd say it was the thermostat again from what you described

 

[stu_b]

kin elll 3rd one in about a year now!
been using ones from Eurocar parts are Audi OEM ones any better and worth the extra ££?

 

[s3 Hoggy]

I had a supposed genuine part fitted by a garage before and it ply lasted a year when I removed the stat it didn't look like a genuine good quality part, I have since fitted a genuine part but that was only 300 miles ago

 

[sportquattro]

Most probably thermostat but, and I had this myself recently, the temp sensors are prone to giving same symptoms. Run VAG-COM and check for codes.

 

[s3dave]

do the 49c check....

 

[MrTackalakalaka]

I have exactly the same problem........ then had a list from Audi of jobs that popped up on their system.


One of them was the coolant temp sensor for £150..........****!!!!!
Thought i better get it done so fitted a new one yesterday and the gauge still floats about, so I'm glad i didn't take it to audi!

Next job is the Thermostat!

 

[hades-]

stat
and thats why i only use oem parts
maybe a few more £££ but only on labout charge or i do them myself

 

[RyanS3TT]

Not meaning to Hi-jack, But recnelty i ahd the same isue, lower temp reading while driving motorway and when a roads it would creap up or coasting or stationary.

I fitted my FMIC and this amde temps go up, i geuss by not giving the radiator as much cool air.

But my Miles per galon has gone up. its up to 420 Miles to a tank, which for me is really good. something like 36-37mpg

 

[MrTackalakalaka]

Not meaning to Hi-jack, But recnelty i ahd the same isue, lower temp reading while driving motorway and when a roads it would creap up or coasting or stationary.

I fitted my FMIC and this amde temps go up, i geuss by not giving the radiator as much cool air.

But my Miles per galon has gone up. its up to 420 Miles to a tank, which for me is really good. something like 36-37mpg

FMIC?

 

[S3featesV9]

Front mount intercooler

 

[slydog18]

stat
and thats why i only use oem parts
maybe a few more £££ but only on labout charge or i do them myself

I also found out that Audi parts have a 2 year warranty according to the parts guy in Watford Audi

 

[stu_b]

sorry chaps been away for the weekend its only a 1.6 8v a to b trundle mobile so no probs with FMIC! its just a daft problem that will niggle me!

whats the 49c check that was mentioned?

off to audi tomrrow to pick up an OEM stat to see if that helps typically enough its been fine all weekend and ive done about 400 miles in it helping the missus move her stuff to a new job its still doing fine on fuel and has been sat bang on 90*c when full warm not a problem

 

[s3dave]

Audi TT Climatronic Climate Control Panel codes: Unlocking t - YouTube