Thermostat

[quattrogary]

A warning to all you aftermarker buyers.Buy genuine parts!Just had to have the front of my car off again due to a faulty aftermarket thermostat.A costly time consuming job on my 2.5 tdi.
Also can a faulty stat effect the cars running in any way?

[Crasher]

You don’t necessarily have to buy genuine parts but you should buy a reputable make, not some white box rubbish. In the example of your thermostat (part number, 078 121 113 G) I totally agree and I never fit anything other than genuine BUT the reason for this in this instance is not that the perfectly acceptable parts from Behr or Wahler are inferior, it is just that for a few pounds more, a genuine part gives you a two year parts and labour warranty for a part which is a huge job to change.

A faulty stat reduces the coolant temperature which makes the ECU add more fuel.