2012 Mk6 Golf 2.0 TDI DSG

KAKADU

New member
Joined
Feb 26, 2021
Messages
5
Hi I have had the above car for just under two years. As part of the sale the garage changed the water pump and main thermostat housing. Since day 1 the temp gauge has been bang on 12 O'clock irrespective of driving conditions, weather and having heaters\air con on.

Prior to this I had a Rover 75 2.0 CDT where I drove over 60,000 miles a year. The above same applied not matter what the tem needle always stuck bang in the middle.

A couple of weeks ago my gold's temp gauge started to fluctuate and I could be driving for 20 mins before it started to move. Normally it would be up to full temp within 5 to 10 mins.

I took it to a local garage and diagnostic showed no error codes so they changed the CTS. Things improved slightly but it still took quite a while for the temp gauge to start moving and perhaps 20 plus of driving before the temp gauge went dead centre. However, it would then keep dropping and rising before it got to 12 O'clock and then when it did it would drop up and down between 10pm and 12 O'clock.

I took it back to the garage and this time they changed thermostat and housing. They told me that it was normal on diesel cars for the gauge to fluctuate. To be honest I have never seen this happen on any of my diesel based cars do this over the last 13 years or so.

They changed the thermostat on Tuesday but the problems are still there. i.e temp gauge taking about 20 mins to move even at 60mph speeds. Temp gauge still fluctuating and taking ages to reach 12 O'clock but then quite quickly dropping back to 10pm and vice versa. The cars interior heaters get up to temp quite quickly.

I don't really want to take the car back to the same garage as when I took it back a second time they said that all they could do was change the main stat.

I did say that I had been on a few VW forums and found that a possible cause could be an inline thermostat that some DSG cars have and that many garages do not know of their existence.

The mechanic told me to keep off of the forums as they are a load of crap and people on them do not know what they are on about. Hence my reluctance to take my car back there.

Any advice would be appreciated before I take it to a different garage next week.
 

Crasher

Administrator
Staff member
Joined
Apr 22, 2006
Messages
26,690
Location
Nottingham, England
Ignore whatever the dash gauge says except in extremism as it will read 90 at a real 77 and still be reading 90 at a real 117, it is calibrated to stop people obsessing about the reading which does work but also can mislead. The gauge is calibrated to not fluctuate but a Diesel, especially a modern CR TDI, does take a long time to produce high level heat as they are more thermally efficient. “Main stat” confuses me, is it a DSG, ahh yes it is... I am reading this in steps. Yes there CAN be an additional fluid cooler stat, send me your REG or VIN in a private conversation. On a side point, that mechanic was spot on, an awful lot of what you read on forums is utter tripe.
 

KAKADU

New member
Joined
Feb 26, 2021
Messages
5
Hi Crasher not sure how to Private Message.

Took car on 23 mile run on dual carriageways at 60 this morning.

Took 15 mins for needle to move.

When it moved it kept dropping back.
Took very short vid of temp gauge etc at end of drive but not sure if I can post it.

Took 50 mins to reach just under 12 0'clock or dead centre but within a minute it had dropped back to about 9pm.

Since I have had the car it has always gone dead centre on temp gauge within ten minutes and never fluctuated.
 

KAKADU

New member
Joined
Feb 26, 2021
Messages
5
Hi Crasher

Photo of temp gauge this morning after 50 mins of drive at between 50 and 60mph after driving approximately 21.5 miles. He got to just before 90 after about 50 mins of driving but quickly dropped back to what you see on the photo. It did also drop a few times when it was rising.
 

Attachments

  • Screenshot_20210227-191750_Photos.jpg
    Screenshot_20210227-191750_Photos.jpg
    806.9 KB · Views: 0

Crasher

Administrator
Staff member
Joined
Apr 22, 2006
Messages
26,690
Location
Nottingham, England
The values the engine ECU and cluster sees need to be viewed in measuring blocks and referenced against what the dash gauge displays whilst driving.
 
Top