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[Varche]

Getting quite dispondent about this.

Had the car six months. First five used hardly any water or oil. The other car lost water and that was part down to heater matrix and part down to suspected RH bank head gasket (or pipe at the back). I am a dab hand at changing hbv for no end result.

Back to current car. It has been getting warmer and so have been using the climate air con (well fan as it needs regassing). I assumed that something in using air con was responsible for the problem. After a short journey of 4 miles the other day I had a great big puddle (pint?) under rear of engine. Assumed it wasn't just condensate. Just done 150 miles today with air con off. No water loss. Got back home and have had air con going , heat, fan, driven about-  nothing. No drops and the level hasn't gone down. Will recheck in the morning. I have the scuttle off and will put a different hbv on in the morning.

It has always run cooler than my other car but I didn't think much of that. Now it seems to run the same - maybe 27deg C ambient causes that?

So what can be causing losses of water varying from a pint, two pints and nothing on similar one hour, 40 mile journeys.?

My neighbours Lada Riva is looking mighty tempting. In fact so is his mule

[Andy B]

.... I assumed that something in using air con was responsible for the problem. After a short journey of 4 miles the other day I had a great big puddle (pint?) under rear of engine. Assumed it wasn't just condensate. Just done 150 miles today with air con off. No water loss.  ....

that's how my car was when the heater by-pass failed.

[feeutfo]

Hbv. Ac diverts the flow through it. Poxy thing. Odds on IMO.

[Captain Slower]

Hmm, this sounding like the problem I have started to get. The coolant warning message popped up yeterday when I first started the car up. Checked the level in the expansion tank and saw that the water was below the sensor so I topped it up. This morning the warning came back. Topped the water up again and drove across town, no more than 3 miles. Bang, the warning is back on and the level has dropped considerably. Cant find any split pipes, no teltale puddles under the car. I have no idea where the water is going. Any suggestions as to what to check/look for in the engine bay?

[Andy B]

Hmm, this sounding like the problem I have started to get. The coolant warning message popped up yeterday when I first started the car up. Checked the level in the expansion tank and saw that the water was below the sensor so I topped it up. This morning the warning came back. Topped the water up again and drove across town, no more than 3 miles. Bang, the warning is back on and the level has dropped considerably. Cant find any split pipes, no teltale puddles under the car. I have no idea where the water is going. Any suggestions as to what to check/look for in the engine bay?

This is the guide for the V6s HBV but I believe the 4 cylinder cars are similar. (God knows why I thought it was a 4 pot  :-? )
 http://www.omegaowners.com/forum/YaBB.pl?num=1193594464

[Varche]

Cpt Slower - One leak I had was the heater matrix itself. damp patches in footwell and more tellingly misted up windscreen inside. There are loads of other places including in the engine V, a pipe down the back of the block near the DIS pack and core plug again down the back of the engine on your V6. Unlikely to be a head gasket but apparently some 98 cars(I believe )could have head gasket failure on the rear back corner. Maybe that is what mine had in the end. I will never know!

Your first port of call is to look at the hbv and the rubber pipes connecting it.

[Captain Slower]

Had a look at that link Andy and got this "This field only accepts numbers from 0-9 Thread ID: '1193594464 '

Not sure what it means.

hbv? , sorry varche, what is that?
Appologies if i'm making this hard work gents.

[Andy B]

Had a look at that link Andy and got this "This field only accepts numbers from 0-9 Thread ID: '1193594464 '

Not sure what it means.

......

It's a glich somewhere ......  :-/ :-/ :-/
this is what I meant to post .... http://www.omegaowners.com/forum/YaBB.pl?num=1193594464

[Varche]

hbv = heaterr bypass valve. Looks like a star trek space craft (though obviously a lot smaller) black. has three pipes carrying water. the valve is operated by vacuum like most everything else on the Omega. The vacuum pipe plugs into the top. GM part number is 90 566 947. Get  agenuine one if yours id bust. Cost about 30 of your sterlings. aftermarket on Ebay much cheaper but don't last. 

[Captain Slower]

Thanks Andy, I've had a look at the "how to" and will have a go once the sun returns, hopefully that'll be tomorrow

[Captain Slower]

Varche, Is it going to be blatently obvious if the hbv is caput?
How does the hbv being broken/faulty cause the loss of water?

[Andy B]

Varche, Is it going to be blatently obvious if the hbv is caput?
How does the hbv being broken/faulty cause the loss of water?

The valve opens & closes using vacuum via a diaphragm inside it. When the diaphragm wears/perishes, it leaks coolant. Watch the valve as the heating is altered from cold to hot and/or the air con is switched on or off. If it's leaking, the above should show it up. 

[Varche]

Sadly no it isn't obvious when you look at it off the car other than it may have brown staining on part of the body. With luck when you put the climate/air con through its various stages heat, cool, screen, off you will get water leaking out. Don't confuse it with condensate off the air con "fridge". That is normal and leaves drops under the car.

Why do they fail. Pretty poor design in my view. The valve actuation is done by vacuum and that operates a diaphram which allows water to go through the other pipe. I believe that the rubber diaphram fails. If only Heineken made diaphrams.

[Captain Slower]

Thinking about this, I turned the aircon on on thursday for the first time in probably a month and fiddled with the temp settings, starting with hi and then seeing how cold the system would go. The water loss was first noticed on Friday. Perhaps that was enough to finish the hbv off if it was already in a fragile state.

[Andy B]

Thinking about this, I turned the aircon on on thursday for the first time in probably a month and fiddled with the temp settings, starting with hi and then seeing how cold the system would go. The water loss was first noticed on Friday. Perhaps that was enough to finish the hbv off if it was already in a fragile state.

Sounds like you've identified your problem. Replacement isn't difficult, just take your time & be methodical, you should have it done in a couple of hours (an hour with practice  )