WD's top tips for Tstat changes

**Wobbly Dave** · Thursday 8th September 2005, 01:40

How to Change your thermostat

You will need
A T40 torx bit
A hose clamp (optional)
Antifreeze/Water mix (50/50)
15mm or 17mm open ended spanner (I forget exactly which)
A new thermostat (obviously)

This is a job best done on a cold engine. But if you are doing it on hot please ensure you slowly release any pressure in the system by undoing the cap on the coolant reservoir - infront of the n/s suspension turret.

The thermostat on a T5 is housed in a case next to the timing belt. If you follow the top hose out of the rad - you will see it. It is secured by 2 T40 torx bolts

On the pre-ME7 models it is good practice to undo the fuel line as it comes over the top nearside end of the head, as this will promote proper access to the rear of 2 torx bolts which you need to undo to get the top of the Thermostat housing off. On ME7 cars this is not necessary as the fuel line does not foul the line of sight to the rear bolt.

Clamp off the top hose (optional) to reduce fluid loss. Undo the fuel line slowly using rags (it might be pressurised) - NO NAKED FLAMES/IGNITION SOURCES!! (as if you didnt already know!!). Move the fuel line to one side, being careful not to kink the solid line. Undo the fuel line clamps 1/2 way across the head if necessary.
YOu can do this job without undoing the fuel line but access to the rear bolt is difficult and you do run the risk of stripping the head.

Undo both torx bolts. I found using long nose pliers essential when removing the bolts - access is fiddly. Remove the top of the housing which is attached to the thin overflow pipe. This too can be a bit fiddly but be patient.

Remove the old Tstat - noting the orientation (spring is on the bottom side)

Some new thermostats dont come with "o"rings - so you will need to renew or reuse depending on condition.

Drop the new Tstat into place and secure the housing. Reattach the fuel line if you have remove it - take care not to cross thread the junction.

Top up the fluid loss from opening, into the coolant reservoir - to the apppropriate level.

Run the car and check that there are no leaks from around the housing.

Splice open a beer and bask in the glory of a job well done!