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[MG]

Hi

I have a 1999 V6 Omega Estate which has developed a coolant leak with the engine running and fully warmed up.

As far as I can see the coolant is pouring out like an open tap from the rear of the engine dropping on the floor from the bell housing area.

Can't see any split hoses.

Any ideas?

Any help or advice fully appreciated.

MG

[Doctor Gollum]

Probably the HBV.

Change the temperature settings on the climate panel to the opposite* and see if the leak stops.

Presumably it's set to LO or just above, so whack it upto HI and report back 

[Migv6 le Frog Fan]

Yep, almost certainly HBV (heater bypass valve). 

[Enceladus]

It might also be the pigtail hose that connects the inlet spigot of the HBV to the spigot at the centre rear of the engine. GM part #90466222. Splits under the clip at the engine spigot end due to old age and heat and nicely showers the bell housing and maybe the coil pack. Very hard to see.

The HBV is more usual but if yours is all right it's probably the hose.

[Alnico Blue]

Removing wipers and scuttle will enable you to get a much better look.   

Wipers/scuttle removal process is covered in the Maintenance Guide - external trim  - wipers/scuttle removal .

[Nick W]

Removing wipers and scuttle will enable you to get a much better look. 

Wipers/scuttle removal process is covered in the Maintenance Guide - external trim  - wipers/scuttle removal .

£2 inspection mirror and a torch which should be in any toolbox

[MG]

Hi thanks everyone!

The leak started after the air conditioning was turned on and set to LO. So that concurs with the Doctor's diagnosis!! On closer inspection the top of the HBV where there is a small oblong opening near the mushroom top of the device, looks a little wet as if coolant may have leaked out. Is this how they fail (normally)?

I have already started dismantling the car - the plenum and the inlet manifolds are off and I have fully inspected all of the heater hoses at the rear. I have identified the HBV and have ordered a replacement from autodoc (which I hope is an OK firm to use).

I can't therefore try Doctor Gollum's test as the car is a bit in pieces at the moment - guess I was a little enthusiastic to try and find a split hose or similar

I have also removed the elbow at the rear of the valley area to try and get a better view of the transfer coolant pipe which I also suspected earlier in my investigation. I can't see any signs of leakage and the way the coolant was pouring out, it could not be a small leak. It was running like a tap, so to speak.

Is there any way of testing the HBV now that I have it removed from the car? Would be very satisfying to 100% identify a failed HBV before I set about re-assembly.

Cheers and best regards to all.

MG

[Nick W]

I have already started dismantling the car - the plenum and the inlet manifolds are off and I have fully inspected all of the heater hoses at the rear. I have identified the HBV and have ordered a replacement from autodoc (which I hope is an OK firm to use).

I can't therefore try Doctor Gollum's test as the car is a bit in pieces at the moment - guess I was a little enthusiastic to try and find a split hose or similar

Is there any way of testing the HBV now that I have it removed from the car? Would be very satisfying to 100% identify a failed HBV before I set about re-assembly.

it's such a common failure, that if you've got it off putting it back isn't worth the £15(or less) saving

[Doctor Gollum]

I have already started dismantling the car - the plenum and the inlet manifolds are off and I have fully inspected all of the heater hoses at the rear. I have identified the HBV and have ordered a replacement from autodoc (which I hope is an OK firm to use).

I can't therefore try Doctor Gollum's test as the car is a bit in pieces at the moment - guess I was a little enthusiastic to try and find a split hose or similar

Is there any way of testing the HBV now that I have it removed from the car? Would be very satisfying to 100% identify a failed HBV before I set about re-assembly.

it's such a common failure, that if you've got it off putting it back isn't worth the £15(or less) saving

This

If it's almost out, throw a new one in 

[MG]

OK many thanks for your encouragement

BTW I mean't to ask is there a part number for the elbow seals and where may I obtain them?

Regards,

MG

[Doctor Gollum]

Dowty washers, from VX with new banjo bolts

[woolley11]

Could be the coolant transfer pipe at rear which is over the bell housing.

There’s a little seal on that that goes brittle/breaks up. A bit of a pig to get to but if you’ve removed plenum etc should be visible. 2 hex bolts and 1 near exhaust O/S heat shield.

[Doctor Gollum]

Never touchedthe coolant bridge on my 285k 3.2... Did have at least 2 hbvs in the six or so years I had it for

[Migv6 le Frog Fan]

Im tempting fate here, but mine has been fine in the four + years Ive has it. I have one or two spare HBV,s in the shed, so ni biggy of it lets go.

[Doctor Gollum]

Im tempting fate here, but mine has been fine in the four + years Ive has it. I have one or two spare HBV,s in the shed, so ni biggy of it lets go.

The do about 80k, so you should be ok for another four

[MG]

Thanks for that - I will order the Dowty's - hopefully can source them OK.


HBV en route from Germany at the moment!

Cheers,

MG

[MG]

Hi

I have had a look around for  Vauxhall spares to source these dowty washers and banjo bolts. I can't seem to find any...am I looking in the wrong place!!

MG

[Doctor Gollum]

Dowty washers, from VX with new banjo bolts

[MG]

Thanks Doctor.

I can't seem to source these....maybe I am looking in the wrong place. Can you give me a website please?

The bolts themselves look OK, however on one bolt the top rubber seal is split and may have been leaking. Is it possible to get rubber washers and the metal washers and re-use the old bolts?

Thanks for all your help.

Regards.

Mel.

[henryd]

Thanks Doctor.

I can't seem to source these....maybe I am looking in the wrong place. Can you give me a website please?

The bolts themselves look OK, however on one bolt the top rubber seal is split and may have been leaking. Is it possible to get rubber washers and the metal washers and re-use the old bolts?

Thanks for all your help.

Regards.

Mel.

https://uk.rs-online.com/web/c/pneumatics-hydraulics-power-transmission/power-transmission-gaskets-seals-packings/seals-o-rings/?applied-dimensions=4294532979
In bags of 50 but not a fortune   

[Doctor Gollum]

Thanks Doctor.

I can't seem to source these....maybe I am looking in the wrong place. Can you give me a website please?

The bolts themselves look OK, however on one bolt the top rubber seal is split and may have been leaking. Is it possible to get rubber washers and the metal washers and re-use the old bolts?

Thanks for all your help.

Regards.

Mel.

Obviously wasn't clear enough... Go to Vauxhall and buy some...

Or buy the bag full that Henry suggested 

[Nick W]

Or take one of them to a hydraulic/pneumatic/fastening/bearing supplier and get them for a few pence each. If you don't bore the counterman with what you want them for, he might not bother charging you at all. This will give you fewer spares than a bag of 50

[MG]

Thanks again!

@Henry: have ordered the RS ones (16.7 x 24 mm) are the perfect match to mine. Guess I will have 46 spares!!

@Doctor Gollum: Did try Vauxhall and it is a real pain to get parts - didn't get anywhere. The nearest Vauxhall dealer really only wants to sell new cars not old ladies like the Omega!! Do you use a particular tame dealer that has a decent parts person that is willing to spend time looking up parts for future reference.

Hopefully get the old girl up and running soon 

Cheers,

Mel.

[Doctor Gollum]

I used to have a tame dealer, but long since gone

Now Vauxhall in Weybridge were always pretty helpful, but equally I have never been afraid to obtain genuine parts from overseas. Obviously it helps to have a part number...

May be worth having a sit down chat with the dealer principle/Aftersales manager, but don't expect much

[MG]

Thanks for all your help. Much obliged.

Hopefully get the Dowty washers today. The HBV seems to still be in Germany....I guess Covid will slow it's delivery. Was hoping to get it buttoned up over the weekend but more likely next weekend now.

Will let you know how I get on.

All the best.

Regards,

Mel.