After the cambelt change the other week, we plugged in the diagnostics gizmo and found that there was an error relating to the coolant temperature sender ( in address 17, not address 01 as might be expected). Cleared it and it went away, then then on Monday I was happily driving down the motorway and noticed that the temperature gauge had dropped to 50, emmissions workshop warning came on and I started to wonder about getting off the motorway, not knowing what effect this was going to have. Car seemed OK, but stuttered as the revs went past the point at which the turbo cut in (about 2,000 rpm.)

Got to where we were going OK and checked with my knowledgeable mate that the car was OK to drive home. Turns out it is, it won't overheat, but fuel consumption may be worse as the ECU will assume that the engine is cold and squirt more fuel in accordingly. Luckily the gauge seemed OK on the way home and all was well.

Today I fitted the new sensor and can't believe what a difference it's made or how easy it was to do it on the V6. Just lift the engine cover and the (green) sensor lives on top and in the middle of the V of the cylinder heads. Small screwdriver to lift the catch on the electrical connector, pull the "lyre" clip out, wiggle out the sensor by hand, maybe 1/4 of a cup of coolant comes out then stops, check that the O ring is out using your finger, push the new sensor and O ring down in, refit the lyre clip and push the electrical connector back on. Job done.

Took the car out to test it and can't believe how smooth and quiet it is now, with shedloads of power and torque as the turbo comes in. As the sensor is a "twin head" job (one for the ECU and one for the dash display), it makes me wonder if it's been intermittently playing up for a while on the ECU side.

The cost? £6 off EBay, £10 at a local motor factors and £40 at the local VW agency. I went for the motor factors first, and think I'm going to order a spare off EBay as it's a common fault apparently and just so easy to change. I'll keep it in the boot just in case the new one fails a long way from home.

Does this look like the right one for the V6 TDi then please? Thanks.

Edited 5 May, 201115 yr by Fred Bloggs

Does this look like the right one for the V6 TDi then please? Thanks.

That's the one. I bought one and it arrived today and it looks identical to the one that came out and the new one that's gone in.

Believe it or not, the green colour is the giveaway. Other sensors on the car are coloured differently.

Thanks.