Omega Owners Forum
Omega Help Area => Omega General Help => Topic started by: NaughtyNigel on 16 June 2009, 11:15:52
-
I have suffered slow coolant leak from my 2.5 V6 (facelift) for two or three years now, but have never found the source. I can nearly always smell hot antifreeze after a journey but until Saturday I have never seen anything.
Coolant consumption seems highest after short (10 ~ 15 mile) journeys, whilst 200 mile journeys use very little at all. Until a week or so ago it was using about one litre of antifreeze per 500 miles on mainly short journeys.
Anyhow, it has been getting much worse recently, and on Saturday, when I changed the front brake disks, I could see telltale pink streaks on both sides of the bell housing aft of the engine. There were also two small pools of antifreeze on the drive.
From what I have read here, this all points to the Heater Bypass Valve (HBV). However, peering behind the right hand side of the engine with a torch and mirror the HBV was perfectly clean, and there was no sign of coolant leakage anywhere around it.
Looking from the left hand side I could just see the top of the ignition coils (DIS Packs?), which were also clean.
So my question is; how, where and why does the HBV leak? And does this sound like a typical HBV leak? If not, where is the coolant most likely to be coming from?
The car has done just over 100,000 miles, the engine oil is perfectly clean and there is no 'mayo' around the filler neck, so I don’t think it is the head gasket or the oil cooler. In all other respects the car starts and runs perfectly.
Any advice would be very welcome as I would like to be able to use the car without worrying about loosing coolant all the time! :)
NN
-
Thats does not sound like a typical HBV leak, its to little for to long.
Yours sounds more like oil cooler plate seal or thermostat seal in the valley area.
-
Thats does not sound like a typical HBV leak, its to little for to long.
Yours sounds more like oil cooler plate seal or thermostat seal in the valley area.
That seems to make sense.
Are these easy enough to change?
NN
-
this will help http://www.omegaowners.com/forum/YaBB.pl?num=1221081908
and for thermostat http://www.omegaowners.com/forum/YaBB.pl?num=1229464812
:y
-
Ahaa. Thanks for that. Looks like my weekend is planned then. :y
NN
-
Thats does not sound like a typical HBV leak, its to little for to long.
Yours sounds more like oil cooler plate seal or thermostat seal in the valley area.
For future reference, what actually happens when the HBV fails? Does it break open or split, or is it less obvious than that?
NN
-
Thats does not sound like a typical HBV leak, its to little for to long.
Yours sounds more like oil cooler plate seal or thermostat seal in the valley area.
For future reference, what actually happens when the HBV fails? Does it break open or split, or is it less obvious than that?
NN
Mine sent a dribble down the rear of the engine.
-
I had much the same symptoms as you and I felt behind the HBV and couldn't feel any coolant so decided to strip the inlets off down to the V - pressuried the system and lo and behold it was ....................HBV so I'd seriously check this one out first altho' taking the inlets out made it an easier job.
My HBV looks perfect from the outside - it's the innards that fail. :y
-
There's a very well-written HBV how-to guide, in the maintenance section. *ahem* ;)
-
There's a very well-written HBV how-to guide, in the maintenance section. *ahem* ;)
I have just found that. Thank you. ;)
NN
-
Thats does not sound like a typical HBV leak, its to little for to long.
Yours sounds more like oil cooler plate seal or thermostat seal in the valley area.
Or coolant bridge.
-
have a look here, http://www.omegaowners.com/forum/YaBB.pl?num=1244468227/15
Covers alternative leak areas other than hbv and tips how to diagnose. Unfortunately most leaks end up dribbling down the back of the engine on the bell housing area.
-
Its strange. I used the car a few times on Sunday, two short (3 mile runs), and two 15 mile runs later in the day. Then my wife took it to work yesterday (11 miles each way). Last night the Coolant Low warning came on, and had to add more than a litre to bring it up to level.
My wife took it to work again today. It lost virtually no coolant today, but it started dribbling an hour or so after she came home. :question
Think I'll see what happens when the heater is turned up full. People here seem to say that turning up the heater can make the HBV leak. :question
-
Its strange. I used the car a few times on Sunday, two short (3 mile runs), and two 15 mile runs later in the day. Then my wife took it to work yesterday (11 miles each way). Last night the Coolant Low warning came on, and had to add more than a litre to bring it up to level.
My wife took it to work again today. It lost virtually no coolant today, but it started dribbling an hour or so after she came home. :question
Think I'll see what happens when the heater is turned up full. People here seem to say that turning up the heater can make the HBV leak. :question
Hbv is actuated by vacume and depends on the climate controle settings as to its position and where its rooting the coolent. It then depends on the exact leak site on the hbv as to what climate setting gives the leak. I presume when the engine is off and the vac is lost the hbv position changes and then it leaks out more dramatically.....Sometimes. Sometimes they leak no matter what.
As said, depends where and how bad the leak is and what the climate settings are. Iirc Mat(in the link) said his leaked steadily for weeks and then it got worse and poored out when engine off. Certainly when we topped it back up and started the engine no leak could be found. When i checked the climate setting it was on"lo", flat out ac. When set to "hi" flat out heat it poored out. No reason to assume yours will behave exactly the same though.
But should give you something to work on. :-)
-
Thanks for that Chris.
I took it to our local independent garage this morning for them to have a look at.
Problem is, about a year ago they diagnosed a failing head gasket, on the grounds that they found Carbon Monoxde gas in the header tank, and they seem reluctant to consider anything else. But what other gas would you find in a coolant header tank anyway?
The coolant had been circulating in the system for around 5 years/50,000 miles, and even a 'perfect' head gasket will be slightly permeable to a small molecule like CO over a long period.
Has anyone here tried using an exhaust gas analyser on a good/newish engine?
Right now I feel as if I am banging my head on a brick wall. I don't mind paying a reasonable amount to get it put right, but I don't want to spend good money on an expensive fix that cannot work.
NN
-
Nigel how far are you from the Scotland Meet tomorrow? I can put a little pressure in the system to find the leak whilst you are there. If it is something I can fix whilst you are there I will :y
Daz
Here is the link
http://www.omegaowners.com/forum/YaBB.pl?num=1244483287
-
Thanks Loo-Knee, that is a great offer.
You are about four hours from me, but it would be worth it to get this problem fixed - or at least to find out what the problem is.
I should know in an hour or two whether the local independent has found anything. They are very good, but as always, time is never on their side.
I will let you know later today. It would be great to come, but I will bring plenty of antifreeze, just in case. ;)
I might even bring my helmet to have a go on that F1SE ;D
Before I go, I have been reading some of the threads about water leaks in the Vee. If I were to remove the plenum chamber, could I see from there where the water was coming from, or would I need to remove the inlet pipes and fuel gubbins as well?
NN
-
Both my 3.0L Omegas suffered coolant leaks recently.
One was actually squirting out from behind the plenum (roughly where the breather hoses attach) when you revved the engine - this turned out to be the hose from the coolant bridge to the HBV had a small nick in it, no idea what had caused this as I'd only had the car a few days.
On the other one it was the HBV itself and it was ok when the climate control was having to produce heat but coolant was trickling off the back of the block when no heating was required. The valve was leaking from the seal on the "plunger" and I guess it'd been sitting in the same position over the winter and spring and only started to leak with the recent warm weather when it needed to bypass the matrix.
So, as already suggested, see if setting it to Lo or Hi makes any difference, if it does then I'd say the problem is the HBV for sure.
With the plenum off you can't really see that much in the V, you've really gotta take the injector manifold and inlet bridge off for a proper look I'm afraid.
-
If you want to see if there is any coolant in the V then remove the 2 front bagpipes which connect to the throttle housing and you will see the thermostat housing - shine a torch in there and you might see coolant (you've got a leak).
For further investigation you will have to remove Plenum, injector bridge and inlet manifold - but it's not a big job and will take an hour or two depending on your expertise. :y
-
Interesting.
One thing I have noticed is that the climate control blows warm-ish air when set to Lo, (engine hot) unless the aircon is switched on. Presumably this means the HBV is not bypassing as it should?
From what you and others have said I am tempted to remove the plenum and the other bits and peices to have a proper look inside the Vee. I will change the plugs whilst I am in there. (They were last done at 60,000 miles ago, but the old ones seemed like new so I haven't done them since). :-[ :)
I guess that removing the plenum will also give a much better view of the HBV behind.
Edit: Just thinking: how is it so many Omega owners seem to live in Scotland? :question :)
NN
-
If you want to see if there is any coolant in the V then remove the 2 front bagpipes which connect to the throttle housing and you will see the thermostat housing - shine a torch in there and you might see coolant (you've got a leak).
That's a good idea... seems so obvious, dunno why I didn't think of that when I was checking mine!
Edit: Just thinking: how is it so many Omega owners seem to live in Scotland? :question :)
Maybe there's just a lot of Jocks on here cos we're too tight to give our money to cowboy garages so we'd rather fix our Migs ourselves! :D
BTW, I'm an ABS and TotalCarlton member too, only recently migrated to an Omega.
-
If you want to see if there is any coolant in the V then remove the 2 front bagpipes which connect to the throttle housing and you will see the thermostat housing - shine a torch in there and you might see coolant (you've got a leak).
That's a good idea... seems so obvious, dunno why I didn't think of that when I was checking mine!
Too obvious! I did't even know there was any fresh air between the cylinder heands and the plenum at the front. Doh! :-[
I'm sure with a small Maglite torch and a mirror I could see enough to work out if the problem is in the Vee or not. That's my next job then. :)
Thinking about it, I have been smelling hot antifreeze for about two years now, but I had never seen anything until last weekend, so the chances are its just been boiling away inside there.
NN
-
Nigel, just spotted you're very close to me. Drop me a PM when you get your car back, if they've found nothing.
-
Thanks for the kind offers of help everyone, but I think decision time has come.
I have just got the miggy back from the local indy garage, and they have confirmed that it is actually the port side (passenger side) head gasket which is bulging out and leaking coolant to the outside world; although the oil remains perfectly clean, and the engine seems to run as well as it ever has done.
They say the starboard side head gasket is doing the same thing, but not as badly.
Looking underneath the plenum from the front of the engine (using a torch) I can see pink staining from the antifreeze along the port side cylinder block.
They have added a professional quality leak sealer to the cooling system (like Rad Weld but better they tell me) to see if that solves the problem for now.
So, the plan is that my wife will continue to use the car for now, and we will see what happens over the next few weeks. I think I am unlikely to pay the going rate for a new head gasket to be fitted (quoted price around £850), and I don’t really have the time or inclination to do the job myself these days. (At one time I wouldn’t have thought twice about it, but that was before the days of Torx fasteners and ECUs). :-/
That being the case I might just revert to Plan A, and offer the old girl for sale to someone here in Omegaland who can nurse her back to health. :'( :'( :'(
NN
(http://www.passionforpaint.co.uk/ap/omega/P4129850.jpg)
-
They have added a professional quality leak sealer to the cooling system (like Rad Weld but better they tell me) to see if that solves the problem for now.
:o
-
They have added a professional quality leak sealer to the cooling system (like Rad Weld but better they tell me) to see if that solves the problem for now.
:o
Not ideal, is it? :(
I think I still might just take the plenum off at the weekend to have a proper look inside.
NN
-
Before you get to upset about your car, it is not unheard of for the head gaskets to go, but I have seen and worked on a number of cars that garages have said the head gasket has gone when it hasn't. If you can make it tomorrow (PM Dave for his address) I will pressure test your car myself and see if they are actually right or not.
If your head gasket was shafted you would be losing water, plus your car would not be running correctly. They could be trying to get £850 off you >:(
For the sake of a ride over to meet some of the guys and gals you could save yourself a few quid :y
Daz
-
Before you get to upset about your car, it is not unheard of for the head gaskets to go, but I have seen and worked on a number of cars that garages have said the head gasket has gone when it hasn't. If you can make it tomorrow (PM Dave for his address) I will pressure test your car myself and see if they are actually right or not.
If your head gasket was shafted you would be losing water, plus your car would not be running correctly. They could be trying to get £850 off you >:(
For the sake of a ride over to meet some of the guys and gals you could save yourself a few quid :y
Daz
So I'm told, they don't actually want to do the job! (Too much other work to take on a big job like head gaskets on a V6 engine).
Right now I am undecided what to do. My plan at present is to remove the plenum and inlet manifolds this weekend to see exactly what is going on. It was leaking again half an hour ago, so I am not too keen on driving it four hours each way!
Anyhow, I will PM you for your address, etc. just in case.
Thanks again.
NN