Symptoms/Reason: Temp needle wouldn't rise to the centre of the guage for at least an hr of driving.. in the winter. Monitoring the coolant temp (on intravee) showed coolant temp was hovering around 70-80C.
Possible causes i've heard of:
1. themostat stuck open.
2. Auxiliary electronic water pump busted.
3. Mechanical air fan jell can harden?, making it continuously cool the radiator
Diagnosis:
Discount 2: my webasto works which depends on the auxiliary water pump, so i knew this wasn't the issue. plus, start the car whilst engine cold, open coolant filler cap, look for a stead jet of water coming in.
Discount 3: air fan could be easily rotated by hand with the engine cold, so i thought it seemed as expected.
I deducted that out of the common causes it had to be 1 above. Not very expensive to try so went for it.
How to:
Buy part number 11517805811 shown here in Real OEM
Remove the air intake, engine cover, and it looks like this, before the fun begins!
Remove A: Air intake to the turbo from the air filter. its only screwed in at the top (air filter end), just pull out from the other end (turbo).
now it looks like this:
Remove A: EGR pipe. it is fitted to the exhaust manifold with 2 torx screws and to the EGR valve with a hose clip. I've heard that the exhaust manifold screws can get fused due to extreme heat, but mine came out no probs.
Next the Thermostat. below pic was taken before the EGR valve was removed but easy to show from this:
Remove A: Unclip and remove this hose first. I removed the thermostat and tried to take this off next, which was a ballache as it was tight!
Remove screws B: 4 of these hold the thermostat in place. These need a female torx set!
Remove the hose on the other side too, that's easy its a simiple clip.
job done, ready for the new thermo!
Some coolant goes waste about a liter i think..
next just fit everything back in reverse order. Everything was easy apart from getting the bottom end of the air intake pipe into the turbo! that was a real pain!
anyways, all done now, coolant topped up, temp needle nicely dead centre!
