How To: VR6 Thermostat Housing Replacment

[mic_VR 3]

After all the fun I had with the replacment of my thermostat housing I decided that maybe a write up was in order.

 

Ok the first thing is to drain the coolant from the system. Found the easiest way to do this was to crawl under the car and undo the drain plug on the underside of the drainage pipe('crackpipe'). Get under the car and look up between the rad and the engine block and you'll see it. Just be careful to have something ready to catch the water and have something to cover your eyes as you will get coolant splash on you.

 

Now remove the plugs from the coilpack and move out of the way, and if you can (I couldn't :( ) remove the plastic cover from on top of the coilpack.

Now undo the four bolts holding the coilpack in place using a 5mm allen key attachment and a socket set, and unclip the electrics and remove/put the coilpack somewhere safe.

 

 

Next thing is to remove the 3 hoses that attach to the housing. Watch the bottom rad hose as there will still be a bit of water left in the rad that hasn't drained off and I also found it easier once i'd removed the fan electrics and tucked out of the way.

 

 

The hoses were a pain in the a*@e to remove and i'll admit that I did swear a little bit at this point, ok a lot! :oops: Make sure you have a good pair of mole grips is my tip and something to ease the hoses off the housing.

 

Ok now disconnect the electrics from the senders and tuck out of the way.

 

The housing is held onto the engine with 3 bolts for which you'll need your 5mm allen key attachment again. The front 2 are easy to get at and are just behind/to the right of the senders.

 

 

The rear one is a bit more tricky (cue more swearing). This one is a short bolt at the back of the housing and is recessed between the housing and the cam chain cover.

 

 

To get this one you'll need a universal joint and extender bar on your socket set but it should come out quite easily.

 

Now you're ready to remove the housing from the car. Pull it towards the battery but you'll need to give it a good bit of force as it'll be quite well attached to the drainage pipe but don't worry, it will go.

 

Now the housing is out of the car, strip it down and check it over for any damage/cracks. Also have a good look at your senders and thermostat for any damage or dodgy looking marks. My thermostat and senders were fine, as were the lower and upper connection joints. The housing though was cracked all around where it attaches to the cylinder head.

 

 

Now it's time to clean up any parts you're not replacing with a cloth and some engine degreasant, I used Auto Glym Engine cleaner as it doesn't corrode plastics. Then you can rebuild your new housing up in the comfort of your kitchen (don't tell the missus) with all new seals, any new parts and all the freshly cleaned old parts.

VW recommend that you put all the seals in dry but I used very very small bit of clean oil to make it easier to put all the parts back together and help the seals sit correctly, but I'm not sure how much difference it makes.

 

Now you'll need to clean up the face on the cylinder head with the engine degreasant and a little bit of emery cloth, you can also check over the electrics and the coilpack and clean/repair as required. My coilpack had a very slight crack so I got some epoxy resin glue on it to make sure it doesn't get any worse.

 

Once all the areas are cleaned time to put the housing back in. Reverse the removal procedure and all should be fine, although I little more swearing my be needed in order the line up the housing ready to put the bolts back in!

VW say you should torque the bolts up to 10nm but my torque wrench doesn't register that low so you'll have to use your better judgement as to how tight you go, sorry I can't be more accurate on this.

 

Then its time to refit all the hoses.

 

TOP TIP - make sure that when you put the hoses back on go: small hose at the front, then bottom rad hose, and lastly top rad hose. Making sure you line up the clips in such a way that it is easy to get at them again at a later date. Believe me, if I ever meet the person who put the ones on my car originally in such a stupid manner I swear I will not be held responsible for my actions :mad:

 

Reconnect all your electrics up to the sender, put the coilpack back in and reattach ALL the spark plug leads :oops: and generally give the engine bay a good clean up and make sure you've not buried any tools in and around the engine area.

 

Then its time to refill with coolant and run up to temp. VW state that you should use a coolant mixture of 35% anti-freeze. As the VR coolant system holds about 9 litres in total I used 3 litres of G12+ coolant and topped up with distilled water. This should give you almost the correct mix, just top up with pure coolent if you lose little amounts to start with.

 

I know that people have differing views on how to fill the system but I filled from the header tank with about 5 litres of the mixture then started the car with the cap off the header tank and slowly filled up with the rest of the mixture as the car warmed, letting all the air out of the system and making sure I had the heating on in the car on max to make sure the heater matrix got filled. Be careful when the car gets up to temp as it can overflow but just get the cap on quickly and you should be ok. Just make sure you take your time and fill slowly.

 

Once the cap is back on make sure all your pipes are warmed up nicely, especially the top and bottom rad hoses. Check all around for any leaks or anything untoward and let it idle for a few more mins. Then, if all is ok and you're feeling brave enough, take it for a spin and enjoy the fruits of your labour! :D

 

Hope this is of help to others and I'd like to give a massive thanks to all those that helped me while I did mine, a special thanks to big_chris1981 for all the advice and all the part numbers which can be found in this thread.

 

http://the-corrado.net/.archive/forum/viewtopic.php?t=54730&highlight=

[mrbeige 0]

Good write up dude. Maybe one of the mods could add this to the Wiki?

[VR6 South 0]

Quality write up. I wish this had been posted earlier as I've just paid for mine to be done.

[CazzaVR 0]

Excellent stuff- defo needs to be in the Wiki! :)

[big_chris1981 0]

glad you had fun fella.

[DanVW 0]

Did it yesterday with Goldie first job on a VR was nice to be able to get to it from the top! I hate having to remove my ps braket to get at the stat on my G60!! :mad:

 

Only thing to mention would be dont get a VW stat get a low temp after market one! The VW ones are s*1t

[Goldie 2]

Good write up, reminds me of yesterday and i can confirm mine is so much healthier with the lower temp thermostat.....

[mic_VR 3]

Cheers guys, only sorry I couldn't get it up in time to help a few of you out.

 

DanVW, Goldie, I used my old thermostat as I've never had a problem with it overheating. I've heard about all the issues with the newer vw ones and tbh I'm taking a bit of a risk not replacing mine while I had the chance.

But I've done about 60/70 miles it in today with plenty varied driving and water temp has been rock steady at 85c all day so fairly happy that all is well.

[dinkus 10]

Top job, sir 8)

 

If you drop Andi a PM, he'll get you sorted out with a wiki login and you can wiki yourself silly :)

[Goldie 2]

mic_VR, If mine had behaved like that i wouldnt have changed it, my car now is a little colder than that but much better than what it was...

 

Did you replace the housing that bolts onto the engine (one with the three senders). If so how much did it set you back??

 

I kept mine but its looking a bit rough in places and will probably need replacing in the future, glad to say its not leaking anymore as the seal was well passed its best..

[mic_VR 3]

Goldie, yeah I replaced the main housing with a new vag part but both of my connection hoses were fine.

 

Part was 021 121 117A and set me back a massive....... £26.87!

 

As for the seals, the one between the housing and the cylinder head wasn't there. Completely destroyed, all that remained one bit about 1cm long attached to the housing.

 

dinkus, I'll send him a PM, cheers mate

[Goldie 2]

I wish id done mine at the same time, 26 quid is ok...

 

My seals were in a similar state.. Oh well i may have to do it all again if the housing gives up....

[trudubrstu 0]

more great info! thanks mic, my mechanics gonna love u for this!

[mattkh 0]

Cheers guys, only sorry I couldn't get it up in time to help a few of you out.[.

 

Hi

 

What a lovely writeup. Thank you.

 

Did you take a photo of the thermostat.

I have read that it can go in two ways. Which is the right way.

 

Also how did you know which order the plug leads went back in.

[mic_VR 3]

trudubrstu, :lol: cheers mate. I aim to please and I'm hoping to speak to Andi about putting it on the wiki.

 

mattkh, Don't worry, the thermostat only really seems go in one way, well on the VR anyway, which was with the spring facing into the housing (makes more sense when you've got it in front of you but you'll see what I mean).

As for the leads, on the VR the coilpack has the numbers on it and you just match it up with the correct lead for that cylinder, which if already clipped into the plastic covers in correct order is quite straight forward. If not the cylinders are numbered as follows (standing in front of the car looking at the engine) back 3 cylinders from left to right are numbers 1, 3, 5. Front 3 (L to R) are 2, 4, 6.

 

Hope this helps

[mattkh 0]

Thanks m8

 

You are a star.

[poll250 0]

Wow that write-up is just what I've been looking for! Thanks alot for going to the trouble.

 

Anyone know where to get these lower temp thermostats from? Any recomendations for model and whatnot!?

 

Andy

[VRTrickster 0]

I got mine from Awesome

 

http://www.awesome-gti.co.uk/

[CazzaVR 0]

Yep, get a Neuspeed one from Awesome. My oil temps are at least 10 C lower since fitting.

[poll250 0]

Well I did the first half of this job today and thanks to this "how to" it was miles easier. Took some pics of the carnage!

 

Problems started early on though with the coolant plug (below) being rounded off:

 

I just let the water drain from the hoses as I disconnected them. This in itself was a bit of a mare as all the clips were underneath the hoses. Nothing a mole grip and alot of swearing couldn't fix though!

 

Then while taking the plugs out I found this!

Think its still ok, just gonna glue it back together?

Anyway, It'd been leaking slowly for a while before it started gushing coolant:

All that rust should clean up easily though with some emery cloth.

 

Finally, got the housing and ancilliaries off pretty easily, took it apart and found the cause of all my problems!

 

This seal somehow got stuck in the thermostat! damm little bugger.

 

I ordered new blue and yellow sensors, and all new housings, seals, gaskets and bolts from vw beforehand, but on further inspection I'm not sure if I need all of it, we'll see in a couple of days when they've managed to get it in, I might just tell them I dont want some bits cos its £110 as it stand plus the £23 for the neuspeed thermo. An expensive exercise all down to a little seal going astray!

 

Thanks again Mic VR for this guide!

 

Andy

[mic_VR 3]

Hey Andy you are more than welcome sir!

 

Even with a write it is still a pain of a job but glad it was worth it and that you found the issue.

 

I had a crack in my coilpack that I found when I did mine, I just got some araldite on it and it's still working perfectly. :D

[ReekieVR 0]

Same here. Cracks in coil pack. Had planned to use J B Weld, but cant find a non internet supplier. I can see you have one on the case too. Same place as mine.

 

Shame i didnt see your post sooner. I just ordered the sensor housing from VW yesterday.

[steve @ 0]

Same here. Cracks in coil pack. Had planned to use J B Weld, but cant find a non internet supplier. I can see you have one on the case too. Same place as mine.

 

Shame i didnt see your post sooner. I just ordered the sensor housing from VW yesterday.

 

Halfrauds sell JB Weld or at least they used to.

[dinkus 10]

Well I did the first half of this job today and thanks to this "how to" it was miles easier. Took some pics of the carnage!

 

Problems started early on though with the coolant plug (below) being rounded off:

 

Probably just as well - that's the oil filter housing! (You'd only have drained the 0.5l or so of oil in the filter housing itself rather than the whole car, but worth knowing)

 

There's a plastic thumbscrew that screws into one of the flexible coolant pipes that's for draining the coolant.

[poll250 0]

I'm not gonna lie, I pretty much put that picture up because I was hoping someone would say something like that. I knew it was meant to have a flathead screwdriver head on but couldnt find it anywhere!

 

Lesson learnt!