Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: mantaray on 09 January 2026, 14:49:33
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Long shot, but does anyone have a coolant transfer pipe for the V6 engine.
Need to do a thermostat change, and I know the transfer pipe is going to brake, so trying to locate one first.
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It shouldn’t break unless you’re really rough with it.
The difficult part is getting the mounting bolt undone. Was for me anyway - goes at a slight upward angle into the block.
Once that’s undone, top hose off, gentle wiggling back & forth should loosen it. Twisting motion rather than just pulling.
Then a good clean, bit of vaso to refit and I was away.
I’ve had the same pipe off & on about three times now with no damage.
Just take it steady.
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Replace the O rings once it's off. ;)
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Replace the O rings once it's off. ;)
Yes, defo have the o-rings - 2 from memory - for the thermostat housing to transfer pipe. Also have an o-ring for the thermostat housing to the block - some thermostats come with them, some don't. Additionally, be aware that if the flags on the new thermostat housing is a different depth, you will need different length bolts as well.
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I had the idea a long time ago that the thermostat could be removed from / replaced in the housing without removing the transfer pipe just just turning the housing upside down in the valley of the engine.
I cant remember whether or not I managed to do it though. :-[ ::) ;D
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....... Additionally, be aware that if the flanges on the new thermostat housing is a different depth, you will need different length bolts as well.
Or a stack of washers .... ::)
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Pretty sure I do. I’ll check when home on Tuesday 👍
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I had the idea a long time ago that the thermostat could be removed from / replaced in the housing without removing the transfer pipe just just turning the housing upside down in the valley of the engine.
I cant remember whether or not I managed to do it though. :-[ ::) ;D
The thermostat can definitely be removed as a separate item, as I’ve done the old boil in the pan to test trick. :y You just push the stat down a couple of millimetres and turn the arms out of the castings. I don’t see why you can’t achieve what you are suggesting. :y
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Which begs the question - why do we go to all that trouble and replace the Stat with housing as a matter of course ? ???
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Which begs the question - why do we go to all that trouble and replace the Stat with housing as a matter of course ? ???
Annoyingly I'd already removed the transfer pipe to do it when I tested mine. ::)
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its because the removeable part of the thermostat is only half of the sealing valve .the other half is the alumunium housing which can become worn and pitted hence leaky !( this is the usual failure mode anyway - letting water past )
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Usual issue though, ime, is lazy Stat resulting in engine struggling to get up to temperature, which doesnt help empeegee figures.
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Which begs the question - why do we go to all that trouble and replace the Stat with housing as a matter of course ? ???
Annoyingly I'd already removed the transfer pipe to do it when I tested mine. ::)
Maybe the pipe still has to be separated from the housing to allow the housing to be turned over far enough to remove and insert the new Stat ?
My memory is so fuzzy ! :-[ ::)
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Which begs the question - why do we go to all that trouble and replace the Stat with housing as a matter of course ? ???
Annoyingly I'd already removed the transfer pipe to do it when I tested mine. ::)
Maybe the pipe still has to be separated from the housing to allow the housing to be turned over far enough to remove and insert the new Stat ?
My memory is so fuzzy ! :-[ ::)
There's not a lot of wiggle room for sure ;)
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You can find stainless steel pipes here https://acsparts.biz/en/cooling-pipe-90411629-opel-ss/
Never used this ACS part but I'm sure it's the same quality level as their oil cooler :y
4 things to know, as it happened when I changed mine this summer :
- The new thermostat housing can have higher cast's dimensions where you put the bolts. I grinded the aluminum of the housing to reuse original bolts.
- The original pipe was very very difficult to remove, even if it was free from any bolt, still impossible to extract. I used a heatgun to locally heat the pipe where it's inside the thermostat housing, in order to dissolve the crap around the o-rings, and it finally worked, without breaking anything.
- Can be useful to remove the 3 electrical plugs aside the ECU box, to clear the space and access.
- New o-rings ordered separately felt very thin and I was not confident with them. I put some Loctite 5923 inside the housing (because if you put directly on the pipe you need too much dexterity to avoid choping the loctite when passing through the tunnel).
I don't know if I'm clear because I feel that I can use more precise vocabulary, which, as a French baguette, I don't have :D
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You can find stainless steel pipes here https://acsparts.biz/en/cooling-pipe-90411629-opel-ss/
Never used this ACS part but I'm sure it's the same quality level as their oil cooler :y
4 things to know, as it happened when I changed mine this summer :
- The new thermostat housing can have higher cast's dimensions where you put the bolts. I grinded the aluminum of the housing to reuse original bolts.
- The original pipe was very very difficult to remove, even if it was free from any bolt, still impossible to extract. I used a heatgun to locally heat the pipe where it's inside the thermostat housing, in order to dissolve the crap around the o-rings, and it finally worked, without breaking anything.
- Can be useful to remove the 3 electrical plugs aside the ECU box, to clear the space and access.
- New o-rings ordered separately felt very thin and I was not confident with them. I put some Loctite 5923 inside the housing (because if you put directly on the pipe you need too much dexterity to avoid choping the loctite when passing through the tunnel).
I don't know if I'm clear because I feel that I can use more precise vocabulary, which, as a French baguette, I don't have :D
Very clear! :y :y
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The link to the stainless pipe is very useful as they are difficult to source these days. :y
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Thanks for all the input, have now sorted the stat, luckily the pipe.came out with little effort.
Interesting to see the the pipe is available.