2L 170 CR DIESEL

the past few months whilst motorway driving, the car never gets up to temperature. it goes up when under load and drops when coasting. When in traffic it reaches 90 degrees and stays there. never overheats. obvious answer is a thermostat stuck open. Main dealer diagnosed a faulty thermostat and replaced it. however the problem still remains.  they had it in the workshop for a further day and are now telling me there is an additional thermostat in the system that 'could' be causing the issue. i've never heard of 2 thermostats in a system. why would you need 2??  any suggestions gratefully received. Thanks

DSG gearbox?

Is it a DSG?

 

 

Yes DSG 

reading previous comments it looks like it could be the DSG thermostat.  you would have thought a main dealer would have been able to diagnose this problem. at the moment i think they're clutching at straws.

 

 

thanks for the above responses.

I’ve read up on this over the last two days as mine has miraculously started doing this too. I was in -8.5’C when it first happened so I assumed it was down to this. From what I have read and deduced, it’s the DSG thermostat which has stuck open. It’s more common than you might think. 

 

the part is about £25 and it looks pretty straightforward to fit (cheap). I will be taking mine in soon. 

To @Bmason2000 - From 10 Problems like Your, 9 was solved with changing the "DSG"-Thermostat

2 hours ago, Bmason2000 said:

. i've never heard of 2 thermostats in a system. why would you need 2??

The DSG oil cooler has its own thermostat separate to the engine's one.

 

 

Plus one for DSG stat and an easy DIY change. Loads of write ups on this forum too. 

Many thanks to everyone who suggested DSG stat. Problem solved. Main dealer not so helpful.

So I’ve still not got round to fixing this (it’s only been a couple of weeks), but my car (100k miles) seems to be puffing out a bit of blue smoke from time to time under acceleration. Is this likely to be as a result of the dpf not getting up to temp? Or is the engine on its way out?

 

to confuse matters even more, it’s just been serviced so maybe they put thinner oil in?

 

any ideas as I’m a bit perplexed. Thanks 

Edited 24 January, 20215 yr by Gremlin170

Mine was the same, DSG thermo changed, back to normal now  .

53 minutes ago, oldian169 said:

Mine was the same, DSG thermo changed, back to normal now  .

With the blue smoke or just the temp?

 

ive been on a few good runs recently, eventually reached abs maintained normal operating temps and there’s been no smoke. Still needs changing at some point I guess.

No blue smoke , just never warmed up used more diesel as well !