coolant Temp

[Audi33]

Hi All,

Firstly I'd like to apologise if there is already a thread for this, but I was unable to find the answer I'm looking for so hear me out..

I have an Audi a4 2010 B8 2.0 tdi 170, which seems to struggle to hold coolant temp at 90 it seems to fluctuate. This seems odd as Every car I've had in the past seems to stick at 90 once fully warmed up .

I have replaced the thermostat and temp sensor with OEM parts and it still does the same. I'm currently getting around 380 miles to a full tank again which is still quite shocking from a 2ltr diesel.

Could this all potentially be linked? Am I missing something? Any advice and help would be greatly appreciated.

 

[JRock247]

I had a similar issue with my previous B8 2.0TDi.

I could go out for a journey, say 10 minutes of driving, temperature reaches 90 and then pull over but keep the engine running and I would see the temp drop by about 15 degrees. Never had a car that has done this before. It would not drop while driving but pulling over for a couple of minutes should not drop the temp by 15 degrees, didn't matter what temp it was outside.

Does it do it while driving or pulled over?

380 miles to a tank! I could easily get 560 miles to a tank in my 2.0Tdi, it was the 143BHp version but still , 380 seems very low.

Have you scanned it with VCDS to check for any errors?

 

[Audi33]

I had a similar issue with my previous B8 2.0TDi.

I could go out for a journey, say 10 minutes of driving, temperature reaches 90 and then pull over but keep the engine running and I would see the temp drop by about 15 degrees. Never had a car that has done this before. It would not drop while driving but pulling over for a couple of minutes should not drop the temp by 15 degrees, didn't matter what temp it was outside.

Does it do it while driving or pulled over?

380 miles to a tank! I could easily get 560 miles to a tank in my 2.0Tdi, it was the 143BHp version but still , 380 seems very low.

Have you scanned it with VCDS to check for any errors?

Thanks for the reply.. I've noticed the temperature dropping off when idle at times but other times when I park up it seems to go up-to 90 and sticks around there for a while.

If the car is being driven soft taking it easy on the throttle I've seen the temp come all the way back down to 50, which seems very strange after the car has been driven for Atleast 20 odd miles.

Yep I have access to vcds and scanned it numerous times but there's no issues. As mentioned above I've changed the CTS & thermostat thinking these could be faulty but again these made no difference.

The cars serviced Every 10k regardless and majority of the time it spends it's time on the motorway. In the past week I've spent near enough £100 on diesel and in return got about 650 miles which to me seems very heavy on juice . my 320d gave me around 650 miles to a full tank which cost me £65-70. Prior to that I owned an Audi a4 b7 2.0tdi 140bhp with a stage one remap that easily gave me around 650+ miles to a tank combined motorways & local pottering.

So I'm at very big loss at the moment. Not really sure on what to do.

 

[Jemster]

Mines the 177 (2015 quattro) and it’s just as cr*p at maintaining temperature. Dealer says it’s normal. Audi say it’s normal. Lots of threads around with similar issues with this engine, and people who’ve done the same as yourself and changed thermostats, all to no avail. I’ve come to the conclusion it’s normal too... but I’m sure it’s not helping the economy.

As for the economy, they are woeful for a 2.0tdi and there’s a few threads about this I’ve found. Ive come to the conclusion Audi lied when quoting their figures (44-60 they say ... measured by dropping the car vertically from space I imagine). I can’t get above about 350 from a tank on mine (if you’re fwd you’ll get a bit more). Long runs I’m getting around 41 on the DIS so about 38-39. More typically, over the past 2500 miles I’ve seen 31mpg (measured with fuelly app).

Mines had the emissions update. I’m thinking of getting it reversed next month when out of warranty, but fear it’ll leave a mark on the ecu so dealers will think it’s tuned. It may not make any difference... but I haven’t anything else to try.

There’s a thread on here with B9 S4 owners who are getting high 30s... I guess I could try that instead

 

[JRock247]

+1 on reversing the Emssions 'Fix'! I noticed a considerable drop in MPG when they applied the 'fix'.

I could get just over 600 miles to a tank before the 'fix', after the 'fix', I could only get around 540 to a tank.

MPG went down by about 4-6 on average. If you have the 'fix', I would get it reverted.

I now have a Golf R and I can easily see 36 - 38mpg on a run!! Manged 36.8mpg on a 28 mile run last night

 

[Retroman]

Some part sites appear to show two different thermostat temperature opening options for your car. One at 82/83 C and another at 87/88C. Just going back over a logical elimination list - are you 100% confident yours has the correct one? Whilst this doesn't apply to me, I've seen some forum talk in the past that certain automatic variants have a second thermostat controlling cooling around the transmission system, which can also stick open.

 

[Audi33]

Thanks for all the input received, I'm assuming it's the right part for this vehicle as I bought it from the main dealers. I haven't had the emissions update done as I read online people were having issues once it was carried out, so the letter went straight in the shredder.

The car is a manual and non quattro so I don't think it has a gearbox thermostat.