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[terry paget]

2008 Vectra 1.8 petrol manual
I have just changed the thermostat and body. On refilling with coolant there is a leak from behind the exhaut manifold. There is a pipe from the water pump to the thermostat, presumably the source of the leak. How do I change that?

[terry paget]

Just a couple of pics. Above is the LH end of the pipe disappearing behind the exhaust manifold

and here is the right hand of the pipe, entering the water pump. Note the bellows to allow for movement in installation. Both pics taken with the manifold heat shield removed.

[dave the builder]

Are you sure the thermostat housing is not cracked (very common) , and the coolant is just running along the pipe ?
best to pinpoint the leak for sure before part swapping
you could pressurize the cooling system with air 

[Doctor Gollum]

Presumably the gasket was replaced prior to refitting.

Also, the 'bellows' are to prevent vibration fatigue, not fitting as the pipe is generally fitted prior to the exhaust manifold...

[terry paget]

Yes, Dave, and have just checked. There is no coolant running along the pipe, but it is still dripping off, and running off the catalyst/front pipe joint, see.

As I suspected, Doc. Next question - will the pipe come off without removing the exhaust manifold? I am hoping if I remove the coolant pump it will come out that way.
The original problem was a coolant leak below the thermostat to pipe joint. To correct this I changed the thermostat and holder, and applied some gasket compound to the square section sealing ring on the pipe LH end.
There was some sort of joint or rubber support in the middle of the pipe, sadly photograph did not show it.
My donor Astra 1.4 is not the same.

[Doctor Gollum]

Manifold off.

iirc, water pump is cambelt driven so there is no way on this planet you will be removing it the way you suggest.

[Doctor Gollum]

Also, coolant should be orange...

[terry paget]

I think coolant pump is aux belt driven, Doc, must be a Z18XER engine. Sorry to hear about the exhaust manifold coming off, though, I have memories of head studs breaking off on Omegas. and that job getting out of hand. and I cannot find any used coolant pipes on e-bay. I wonder if Vx still stock them?
Wife says I should stop doing car repairs. I wonder what a garage would charge for the job?

[Nick W]

I don't think you should stop doing car repairs Terry.


I do think you should get somebody else to buy the cars for you.

[biggriffin]

I don't think you should stop doing car repairs Terry.


I do think you should get somebody else to buy the cars for you.

 Couldn't have put it any better.

[terry paget]

Thanks gentlemen, I accept exhaust manifold has to come off. Haynes gives it 3 spanners, so not too difficult. Trouble is, he dismantled a new car, my car is 14 years old. I had the heat shield off yesterday, that was half the job.

 Next time I must cork the dip stick hole to avoid oil loss.
Any tips on removing the removing the screws attaching exhaust front section to manicat?
Do the manifold and the catalyst form one item, the manicat?
Is there any way I can facilitate removing manifold to head nuts from studs?
I imagine the pipe is cracked. Both ends appear to have 'O' ring or similar joints. Pipe looks like stainless steel. Will it be repairable?

[Viral_Jim]

I suspect removing the manifold will be a serious pain in the Arris. I'll bet a tidy sum that you'll end up having to drill out snapped studs and all sorts of other sh!te.

Is there an option of cutting the old hose to remove and then re-routing using a longer flexible coolant hose, such as used by kit car builders. E.g.

https://www.carbuilder.com/uk/38mm-id-x-450mm-long-vulcoflex-flexible-coolant-hose

[terry paget]

I suspect removing the manifold will be a serious pain in the Arris. I'll bet a tidy sum that you'll end up having to drill out snapped studs and all sorts of other sh!te.

Is there an option of cutting the old hose to remove and then re-routing using a longer flexible coolant hose, such as used by kit car builders. E.g.

https://www.carbuilder.com/uk/38mm-id-x-450mm-long-vulcoflex-flexible-coolant-hose

I don't think I have a choice. I am aware of the risk if studs breaking off in the head, I have been there before on Omega2s and 2.2s. I enquired about means of avoiding this. I presume it is studs in the head and nuts on them. Posibly a little heat might help, but the head is aluminium alloy, so care is necessary. I have bought cars with the odd stud missing and the gasket still holding. I again invite suggestions. I had no trouble on Omega V6 cars,nor indeed on my first Omega 2 litre, just lucky I suppose.
 

[Doctor Gollum]

Pressure test the cooling system first, the source of the leak may well become more apparent. 

[terry paget]

Pressure test the cooling system first, the source of the leak may well become more apparent. 

Good suggestion, something I have never done. I have a brake bleeding kit which pressurise the master cylinder using he spare wheel, is that any use?