Petrol 2.0 20V Thermostat Replacement

[pontyslapper]

Does anyone have any idea where the thermostat is located on a 2004 2.0 20V petrol passat with engine code ALT.

It is not on the back of the block housed with the temperature sender unit - we had that apart last night - If you do it, make sure the car is COLD!

I have the FiL looking on Autodata today, all I can find is the 'big' expensive (£50 odd) thermostat - please tell me thats not the only one on the car and it has a more 'traditional' one?!?

[pontyslapper]

Right - found it.

Its under the manifold - in the block behind the large black plastic moulding that has a few coolant pipes going into/out of it.

No chance of 'doing it' without removing the bumper etc/putting the car into 'service position' - this is a minimum of 45-60 minutes each side of an easy job!

We're at the stage where most of the 'service position' is done - just have to pull the rads forward, take the alternator off and then do the thermostat.

Photos and writeup to follow - there's so much differing info out there, that some more in the mix might help someone else with a 'normal sized' Petrol 'ssat rather than TDi's or petrol stuff over 2.3L as most petrol instructions come from US bods with V6's and other 'large' stuff!

[cruiser647]

Sorry! I was going to look it up on ETKA.

[pontyslapper]

Right here goes - sorry no actual photos from me as by the time my Scouts meeting had finished and I arrived at the garage, FiL and mate had done the 'easy' part and were just starting putting stuff back together.

If you have access to a garage ramp - so much the better. A mate is a must have - if only to pass and fetch in the main, but also to help with the lock carrier bit!

Firstly, print off and LAMINATE the stuff from the following link:-

Putting the B5.5 Passat lock carrier in the service position

This will be your bible - it will allow you to see whats coming on what I thought was the scariest bit - 'taking the front' off the car!!

TAKE YOUR TIME - ITS NOT A RACE!

INSTRUCTIONS

1. Work your way through the lock carrier service printouts from above. Your choice as to whether you go the 'whole hog' and have it all off or just move the front forward a bit - we moved it forward a bit, but also removed the lights, but left the grille 'dangling' on the bonnet opener catch.

Might be an idea to have some envelopes/pen/plastic tray for the nuts/bolts etc - we had 2 tubs - one for 'outer' stuff from the lock carrier/lights/undertrays etc and one for 'inner' stuff - the nuts/bolts/etc from the actual engine part.

2. Feel behind the viscous coupling fan into its 'centre housing' - big black fan with silver finned 'drum' holding it onto engine, next to alternator. You'll feel a nut that needs an Allen key to undo it. This will remove the viscous coupling fan, and allow you to get the alternator out. We undid the 4 screws holding the fan to the housing and more than doubled our work!

3. Remove the alternator, if you haven't done part 2 you'll be going back to it - you ain't getting the front left bolt out of the engine unless part 2 is done - you'll see what I mean when you do it!

4. Gently unhitch all the 'jubilee' clip things on the inlet manifold. Then undo the bolt on the bottom of the bracket that holds it in position, down 'behind' the alternator space. This will allow you to move the inlet manifold sideways just enough to wiggle the thermostat housing free.

5. Unbolt the thermostat housing - its only 2 bolts, right on the engine block next to the mounting that holds the alternator. Let the wiggling begin - just enough to slacken it.

6. Undo the bolt holding the black metal pipe on the 'side' of the housing. Now unclip the blue electrical connection to the rear side of the housing. Now you have to ease the inlet manifold sideways so you can wiggle the thermostat housing free. Undo the other hoses that are attached to the housing - taking care with the hoses - on each of the places where the hoses attach to the housing, they have to be worked over stubborn 'bumps' - BE CAREFUL, you may damage your hoses doing this!

7. Don't bother examining the internals - I'll assume you've paid about £50 odd for the new thermostat housing and that contains the whole kit and caboodle, including a new electrical connector - well ours did, luckily!

8. Bolt the new housing in place, making sure you put the rubber O ring in place in the hole on the engine block.

9. Now gently reconnect all the hoses, and work backwards to reconnect/reattach all your bolts etc.

10. Top up/refill the coolant and run the car - check for leaks - sort them if you find any.

11. When you are happy, start reversing the 'lock carrier service position' that you put the car in at the start.

It took us way longer than it should have - mainly down to having no real instructions or a Haynes manual, and the fact we were only able to spare the odd few hours here and there.

If you make a concentrated effort - it should be do-able in around 3-4 hours

You undertake this at your own risk, and bear in mind, this is for the 2.0 20V ALT engine - it maybe useful instruction for the same engine from the Audi A4/A6 but I've not seen those engines and don't know if they are the same engine code.

VW estimate about 2-3 hours for this, so at VW prices you'd be looking at around £300 for this job in the main dealers, whereas you could save about £250 for several hours of your own time!

[pontyslapper]

Picture showing the rear of the viscous fan for part 2 of the instructions. Sorry its the only picture I have - it was the only way to find out what was behind the fan - dangle my N97 mini behind it and get a fuzzy shot! The alternator 'shelf' can be seen at the top of the picture. The alternator bolt comes out and hits the rear of the shiny metal fins.

Oh so technical - sorry about my poor grasp of engine type terms, I'm only an ICT teacher after all!