Hello ladies and gents, been a lurker for years but today I need assistance from the hive mind. 

 

I recently bought a 2014 Superb estate, 2.0 TDI CFFB.  On the test drive I could tell the water temperature was slow to warm up.  My old TT TDI had been like that, I replaced the stat and all was well in the world. 

I did a big service on the Superb, including the stat, and lo and behold the temperature issue is basically the same. 

The stat I fitted was basically no brand from GSF, but I trust GSF usually.  Ive done research and found there are loads of people with DSG stat issues and older Audis with oil cooler thermostats and one way valves. 

 

Ive been through ETKA, I cannot find similar on my CFFB, Ive been under the bonnet this afternoon, no sign of additional stats.  Ive ordered a new stat from my local audi dealer, should be arriving tomorrow but this seems like a common pattern. 

What am I missing?  Do the manual cars have additional temperature controls? 

Thanks

I have the same car as you, same year & engine, manual gearbox.

 

I've been over it with a fairly fine tooth combe in the past & never found a second stat.

 

It does take a good 5/6 miles to get up to temp ( 90 on the gauge ). 

Thanks for your reply!  Ive been through ETKA, checked the part number for ever component, no signs, been back under the bonnet, no sign either. 

 

 Its a bit slow getting to 90* but on cold days, when im in 50mph average sections the temp can drop and if I have the heater on while stationary, itll drop, I made a video below (tried to attach but was too big)

 

Ive just spent another £50 on a genuine VAG stat.  I just hope im not spending more money and time chasing the wrong thing. 

 

Im wondering if its an issue with the electronic water pump? 

https://photos.app.goo.gl/sEWDYPi4HWfHRfth6

Once mine gets to 90 it stays there, no drop off at all.

 

There is no electronic water pump on the CFFB engine, they only started fitting it to the EA288 engine from 2015.

 

There is an auxiliary electric pump that circulates coolant to the EGR. 

Had that fail on my previous Passat, but it made no discernible difference to the engine running or temperature at all when failed.

So I had my suspicions regarding the EGR water pump (the electronic pump below the thermostat) so on the way home today I logged anything I could find relating to coolant temperature and I found

 

Temp sensor for EGR after cooler: raw value: -270.6 °C

 

also Exh. gas recirc, cooler pump, specified value:  95%

 

Im guessing thats showing duty cycle.  The pump is working overtime and overcooling the engine??  Also, in 40mph traffic, I can set my heating to hi, turn everything up and get the coolant temp to drop into the 70s

 

So potentially still a bad stat.  I water logging temperature of radiator outlet and that stayed as high teens, if the stat closed Id have thought itd drop

 

Also the egr coolant temp sensor needs attention.  Either a new sensor or check the wiring, Im guessing it has been damaged when the timing belt was done last

Just as an update, I went out there today with a new stat that I bought from Audi (nearest VAG place), the Audi one fitted better (oring on the aftermarket one was slightly too large so the excess was pinching etc). 

All reassembled, refilled, tested.  The coolant temp will drop from 90* if youre driving at residential area speed with the heating on full. 

The aftermarket stat lets water through to the rad even at ambient temperature, totally faulty.  Shame on me for not practising what I preach, I wont be getting stung by that again, its a **** of a job to change the stat on these TDIs

Even reputable aftermarket thermostats I have known people use have been rubbish. Have to go OEM every time or do the job twice. 

On 14/02/2021 at 18:03, Matt_82 said:

Just as an update, I went out there today with a new stat that I bought from Audi (nearest VAG place), the Audi one fitted better (oring on the aftermarket one was slightly too large so the excess was pinching etc). 

All reassembled, refilled, tested.  The coolant temp will drop from 90* if youre driving at residential area speed with the heating on full. 

The aftermarket stat lets water through to the rad even at ambient temperature, totally faulty.  Shame on me for not practising what I preach, I wont be getting stung by that again, its a **** of a job to change the stat on these TDIs

Did you fix the isse with the second new thermostat? Was it the 4/2 Way Valve and Thermostat?

Thanks

How do you replace the stat on one of these. As you say initially looks awkward?

A few steps would be good please.

What engine code you have?