ED30 not reaching temperature

[MrChin]

Hi - I have an 2007 Edition 30 DSG that will not reach temperature.  It takes a long time to warm up and normally reaches 75-80, will get to 90 on extended runs but will drop down again.  To try to fix this the main thermostat was replaced along with both the coolant temperature sensors and then the DSG inline.  The main thermostat was a BEHR MAHLE TI 6 80, part number 06F121111H (part number advised by vw-classic-parts based on my VIN and ED30 BYD engine code).  I've read countless threads on this, some imply there is a 3rd inline Thermostat for the DSG model depending on the year.  Are there any other potential causes of this temperature issue that I can explore?  Help really appreciated to finally fix this!!

[mjmallia]

The inline stat that usually causes this issue is between the alternator and radiator if the one on the DSG box and the main engine one has been changed.

[FatWelshBoy]

I was under the impression an inline thermostat will just cause the coolant to take a long time to reach temp but it will stay there when it does? I stupidly replaced my thermostat when getting a RFD fitted, the new thermostat from TPS never reached temp so I paid to have another from TPS fitted. This one is better but not perfect, I can get the temp to drop off 90⁰ by putting the heaters on full. What I'm saying is don't think that because it's a new thermostat it's not faulty.

[mjmallia]

Mine used to fluctuate between 70 and 90 or on colder days never get to 90.

The inline one that I mentioned was stuck open. Once I replaced it, the car got to 90 in about 10 minutes and stuck there.

[mjmallia]

Looking from under the car up.

[MrChin]

Thanks @mjmallia, appreciate the response and the picture, really helpful.  I'll investigate this and see how I get on.