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[Alex Wood]

Has anyone had trouble releasing this from the head?

My car started running really hot, even at motorway speeds, so I have tomorrow off to replace rad and thermostat (need car for work and can't spend time figuring out what the cause is!).

Started removing stuff this eve to give myself a head start. Rad is out and I just about managed to undo the nut holding the coolant transfer pipe to the head. After 45 minutes of heaving and wiggling and a couple of tentative attempts at levering I've packed up for the day.

Is there a knack to removing this pipe? Haynes says to "withdraw" it.  

[Mike Collins]

My way of separating the thermostat housing from the transfer pipe is a die grinder. Very carefully grind a slot in the socket in the thermostat housing, then use a large screwdriver to crack the socket. So far the pipe has separated without damage.

You were going to change the housing and O rings anyway. On my first attempt at separation, before trying this method, I broke the transfer pipe. Two days to obtain a replacement.

[carlos_fandango]

Never done it on 3.0 but perhaps some soft jawwed plumbing pliers, grease and a hammer if ya can get on it with them?  :question

[rickyboy]

Probably quite a bit of corrosion in there and it can be tricky to remove.  Perserverance I'm afraid!!!  

[Alex Wood]

Blimey! Will the pipe come out complete with the thermostat housing or is there not enough room in the V to lift them out? My thinking is if I can at least get them out together I can try and separate them without all them orrible pipes in the way.

This is my first V6 and I'm a bit scared!

[Big_Roger]

Hi,
This is a common problem. If the "O" rings sealing the transfer pipe into the thermostat housing have been leaking, then there will be a lot of crud built up siezing it and stopping you from turning and removing the pipe.

As the new thermostat comes complete with the housing, sometimes penetrating oil and lot of tapping of where pipe goes into housing may help to release it without the worry of damage.

If this fails, then you have to hammer and chisel to split the thermostat housing, or maybe you have a small angle grinder to grind a vee in the boss and split it.

I would advise that you also get a new transfer pipe and "O" rings, as even if you do release it, it may well be pitted and difficult to get a good seal in the new thermostat.

Also, a word of caution, if your new thermostat has a thinner flange than the old, make sure you use shorter bolts, at least in the rear thermostat fixing hole, as it is a blind tapped hole.
Also, have you got a new seal ring for the thermostat as well. my new stat didn't have one supplied, had to get separately. A smear of grease around  "O" rings helps to get pipe back in.

I also found it easier when re fixing the transfer pipe, to use an 8mm hex head bolt instead of the torx head one, I found it's easier to locate and get started if you can use a deep ofset ring spanner.

Roger

[Big_Roger]

Hi,
No, the pipe and thermostat housing will not come out while joined together. At least not until you remove the cambelt cover and the camshaft and all that entails!!!

Roger

[Alex Wood]

Ah ok - but I'm guessing that taking the plenum off will expose the area around the join so it can be tapped while the other end is wiggled! I'll give that a go and order the new transfer pipe and o-rings. Wonder what the chances are of geting them tomorrow! Cheers fellas.

[Big_Roger]

Hi, you never know, I was amazed, my dealer got one sent from another branch within an hour.

Other tip, don't undo the thermostat until you have got the pipe out.
After a lot of tapping and penetrating oil, mine finally turned using a pair of Stillsons, but it was slightly distorted.

When you do get to putting back, don't be tempted to discard the engine lifting bracket, it also acts as a spacer to get pipe in correct place.

Roger

[cbs2]

Ah, the b'stard bolt, I remember it well
I had to drill a slot in the housing & open it with a chisel to release it.
Then spent hours trying to get the bolt back in. dropped it several times. in the end cable tied the transfer pipe in tight to the thermostat till the stevie put it back together

[Alex Wood]

Gulp..... Right, my new transfer pipe wil lbe ready for collection at 14:00, as will my new rad. I've just had the old one flow-tested and he says it flows ok but there's a load of silt coming out of it. Recore costs £125 + VAT and new rad on TC from Vauxhall is £167 + VAT so I'm getting a new one, might as well do it properly.

Rain has stopped so off I go to get the plenum off and try again to shift this pipe!

[ians]

As I recall Haynes make this job sound like 5 minutes with one hand tied behind your back.   No mention of the problems getting the b@stard bolt out and back in , or difficulties releasing the transfer pipe.

One of my standing complaints with Haynes is they always assume the car is in pristine new condition, nothing seized or corroded, so they don't deal with these practical issues that we all face.

[humbucker]

nightmare. when changing my oil cooler and thermostat this 'bastd bolt' was the one thing that held me up more than anything else. assistance from serek and others on the forum got me through it but to get that far in and then grind to a halt over something so minor was a real kick in the teeth!! good luck with it; putting it back in is more hassle than getting it out f'sure!

[Alex Wood]

You weren't kidding about the bolt! I lost it three times, the third time for an hour at which point I got on with other things until it reappeared, happens sometimes! New thermostat, transfer pipe and spark plugs fitted, plenum and cover back on. New rad is going in tomorrow morning. Plugs were dry, which was nice, and they didn't half squeak when I undid them. New ones went in ok with a blob of copper grease.

If it leaks or heats up once it's back together I'll not be happy!

[Darth Loo-knee]

I left the Bastard bolt fastened, undid the thermostat housing bolts, got some Mole grips on the housing then wiggled the housing until it was free. Then undid the Bastard bolt to move the transfer pipe slightly to enable me to remove the thermostat