Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[oregad]

Hio, first post hope not last.

So I've had this omega for 2 months now, stomped to discover oil in water, dreaded.

Also have niagria-fall waterleak in the rear side of the engine (opting it's the oil cooler though, havn't looked too deep into it) since bought.

What else can it be. . And how hard is it to break the engine in two and change HG? Never done no more advanced than timing belts ... im big blue right now.

[dave the builder]

Could well be the OIL cooler failed
the coolant leak at the rear of engine could be HBV (heater bypass valve) very common fail 
https://www.ebay.co.uk/itm/193264835590
Welcome to the Forum 

[oregad]

Could well be the OIL cooler failed
the coolant leak at the rear of engine could be HBV (heater bypass valve) very common fail 
https://www.ebay.co.uk/itm/193264835590
Welcome to the Forum 

Hio Dave!

Fingers crossed. Guess it doesn't add up not checking. But im stomped, Dead end big sad right now, cant even eat lol.

Yeah, the HBV ... strange thing, why doesnt 20xev have it? Must be something about higher pressure in the v6.
Anyway, yeah it was leaking. Swapped it recently, not the hoses though. But it was spraying a mist of coolant when it became active. Never seen anything like it.

[oregad]

Car is running great, revving as it should. No other symtoms of it being HG other than, yeah ... oily water (and some silly smoke, but not excessive), oh and also the ridiculous leak, empties itself when driving normally. Not while idle though. No water in oil so what ever.

found the oily water just now, after doing some not-so-kosher intervention to the coolant water.

Why im asking here. Hate even to think pulling the plenum apart. It's not that bad, is it?

[Doctor Gollum]

The HBV leak may be slowdd by adjusting the cabin temperature settings to the opposite of what they are now, which I appreciate won't be great given your location.

That part is typically €20 and can be considered a service item.

Oil cooler failure is unfortunately going to involve a creative solution as they are less common than a zero alcohol Finnish vodka in a bar.

[oregad]

The HBV leak may be slowdd by adjusting the cabin temperature settings to the opposite of what they are now, which I appreciate won't be great given your location.

That part is typically €20 and can be considered a service item.

Oil cooler failure is unfortunately going to involve a creative solution as they are less common than a zero alcohol Finnish vodka in a bar.

Allready swapped the HBV (which was leaky), identified the leak from the back of the block with my finger. Thought I felt it from the centre, not above where the oil cooler is, i.e. no hose leakage as I would persume.
Silly question, regarding it's an oil cooler, but would it contaminate the water? No water in oil.

Maybe an idea pressure-testing and having an inspection camera at the back would be an idea to visibily see the leak...

Any ideas or thread of these creative solutions regarding the oil cooler? Haynes only recommend putting (vauxhall) "sealant 15 03 296" in the groove and new sealing washer on the pipe union.

[BazaJT]

Oil cooler failure is typically seen by oil in the coolant[but not the other way round]swapping one is not a particularly difficult job and I believe there's a guide on here in the maintenance section on how to do it.
I understand that some cars[about 1998?] had a problem with head gaskets leaking to the outside of the head/block towards the rear but others would know better about this than me.

[countrywoman]

Just fitted a Vectra stainless oil cooler to my 3.0L , okay it was in the engine stand so a bit easier but not to bad. In the car it would be a fair bit of stripping down just to get the oil pipes out of the way.

[oregad]

Oil cooler failure is typically seen by oil in the coolant[but not the other way round]swapping one is not a particularly difficult job and I believe there's a guide on here in the maintenance section on how to do it.
I understand that some cars[about 1998?] had a problem with head gaskets leaking to the outside of the head/block towards the rear but others would know better about this than me.

Said to the one having a 98 mv6 with leakage at pressure behind the head/block. BAH 

[Doctor Gollum]

Oil cooler failure is typically seen by oil in the coolant[but not the other way round]swapping one is not a particularly difficult job and I believe there's a guide on here in the maintenance section on how to do it.
I understand that some cars[about 1998?] had a problem with head gaskets leaking to the outside of the head/block towards the rear but others would know better about this than me.

Said to the one having a 98 mv6 with leakage at pressure behind the head/block. BAH 

Panic not, that's usually a weep. 

When the HBV fails it will dump coolant as fast as the waterpump can supply it. As you've recently discovered.

[oregad]

Oil cooler failure is typically seen by oil in the coolant[but not the other way round]swapping one is not a particularly difficult job and I believe there's a guide on here in the maintenance section on how to do it.
I understand that some cars[about 1998?] had a problem with head gaskets leaking to the outside of the head/block towards the rear but others would know better about this than me.

Said to the one having a 98 mv6 with leakage at pressure behind the head/block. BAH 

Panic not, that's usually a weep. 

When the HBV fails it will dump coolant as fast as the waterpump can supply it. As you've recently discovered.

Third time's a charm, it's most likely not the HBV as I've allready changed the piece. Checked all hoses and non is wet, while there were liquid around the block/head. Running down the left side of the gearbox.

Started the bastard today and talking about weeps, more smoke than I'm comfortable with was pushing its way out of the exhaust-pipe. Gotta pull the plenum off and have a look before doing any more time with engine on. Anxiety-triggering car right now..

[Doctor Gollum]

In which case there's some good news and some bad news.

The good news is that you know what the problem is

The bad news?

Well, you know what the problem is...

[oregad]

In which case there's some good news and some bad news.

The good news is that you know what the problem is

The bad news?

Well, you know what the problem is...

Double up the bad news, only got outside parking. On a crossroad, either i fix it (dyi) or I put it aside and wait for a time to place another engine in. Lovely machine except the engine at this moment.

Cant be 100% right now it's the HG though, as I havn't pulled the plenum off, is it wishful thinking?    Hit the jackpot, that's for sure.

Wish I had a workshop, turboboosted saab engine+omega body is win.

[Doctor Gollum]

Replacing the head gasket is a straight forward job, slightly complicated by doing it twice, once for each bank.

Probably €3-400 in parts if you just replace the head gaskets, cambelt and head bolts and a weekends work. Cambelt is the only tricky part in terms of the actual doings.

[oregad]

Thanks for the reinforcement of confidence!

Gotta locate the leak for starters.
Went out to the car just now, only to find that it had barfed out the complete expansion tank (above the lower hose) of coolant under itself (within matter of hours while coldstart -> ran for 30 sec), nothing new.
Makes me wonder though, Holds water while just standing, apperantly loses 1L at just turning over. No contamination of water in oil as i've seen.

[Doctor Gollum]

The water pump only pumps when it's running. There's not much water in the head to leak down without pressure from the pump. 

[oregad]

Got to find another cap for the expansiontank, going to put in a bicycle-valve in it, low budget pressure-tester. Then pull the plenum off, have my doubts it's the HG, but you never know, to be continued... baw

[Doctor Gollum]

MarkDTM did a pretty detailed post regarding the V6 HG failure.

Basically, when it fails on the Omega it does so in such a way that coolant leaks out of the gasket rather than mixing with oil. When the HG failure gets worse, the failure point allows water into the #6 cylinder but not the oil passages because where the gasket fails first is between the water passage and the back of the engine and, then secondly, between the water passage and the cyinder. This means that it leaks coolant externally as the mode of failure and in to the cylinder only when the engine is running and at no point do the water and oil passages become connected.

This is in contrast to the oil cooler fail which sees the oil pump force oil into the cooler without allowing coolant into the oil, even though this is often misdiagnosed as HG failure.

Once the head comes off, the point of failure will be immediately obvious, at on the back left corner.

[oregad]

MarkDTM did a pretty detailed post regarding the V6 HG failure.

Basically, when it fails on the Omega it does so in such a way that coolant leaks out of the gasket rather than mixing with oil. When the HG failure gets worse, the failure point allows water into the #6 cylinder but not the oil passages because where the gasket fails first is between the water passage and the back of the engine and, then secondly, between the water passage and the cyinder. This means that it leaks coolant externally as the mode of failure and in to the cylinder only when the engine is running and at no point do the water and oil passages become connected.

This is in contrast to the oil cooler fail which sees the oil pump force oil into the cooler without allowing coolant into the oil, even though this is often misdiagnosed as HG failure.

Once the head comes off, the point of failure will be immediately obvious, at on the back left corner.

You're a champ for the recap, thank you very much. Dreading to pull it apart in a parking lot though, but what can one do...

[Doctor Gollum]

It's only 30ish bolts and the cambelt

[Nick W]

It's only 30ish bolts and the cambelt

Head gaskets aren't difficult, but there's a lot of stuff to remove first that's at least half the job time.


And you do need to seriously consider the while you're in there parts: thermostat is easy with the belt-cover backing plate off. and I bet the engine end of the top hose is in a state; it's not worth putting suspect coil/leads back; how good is your oil cooler; if you're considering upgrading to the later manifolds do it now(they're really not worth the grief of fitting them any other way); V6s are always covered in oil and other crap so there's a lot of cleaning to, if only so you don't look as if you fell down a coal mine; etc etc

[Marks DTM Calib]

Its pretty much impossible for oil to get into the water via a failed headgasket, its usually the other way round (water in the oil) or water in the bores, or just water leaking.

The basics are that a headgasket has only one high pressure area for oil (to feed oil to the cam bearings and followers) and its very well protected by integrated rings and seals, to get oil into the water jacket would require this high pressure oil feed area to fail and get into the above atmospheric pressure coolant (which it is most of the time).

The one place oil can get into the coolant is the oil cooler 

[TheBoy]

Its fairly well known that Omega V6's never suffer HG failures.  Except mine. Twice


(For clarity, some early 1998 model year (so mid 1997 manufacturer) do suffer an issue where coolant leaks out the back of the 2/4/6 bank.  All others are near bulletproof).  As DTM and others say, on the Omega, the only way to get oil in the coolant is due to an oil cooler failure.

[oregad]

Allready changed thermostat, hbv, coils and dis-pack what else woild there be to consider changing?
Genuine VX-dealer gasket or £300 full set for rocker, head, intake with NN brand?

Its pretty much impossible for oil to get into the water via a failed headgasket, its usually the other way round (water in the oil) or water in the bores, or just water leaking.

The basics are that a headgasket has only one high pressure area for oil (to feed oil to the cam bearings and followers) and its very well protected by integrated rings and seals, to get oil into the water jacket would require this high pressure oil feed area to fail and get into the above atmospheric pressure coolant (which it is most of the time).

The one place oil can get into the coolant is the oil cooler 

Awesome answer. So there might be a chance in hell I'm on the wrong track and just need to seal the oil cooker.

Engine (usually) run great, recently it misses a sparks at idle quite random, as said, no watery oil.
Smokey exhaust (humidity 77% & 1°C outside, lovely weather), was way worse when 1st cyl was dead due to DIS-pack died cause corrosion.
Smokey oilcap when hot, dipstick. Not excessive or pressurising. Might be smelly, no idea.
Yeah, and ... draining water quicker than a drunk.

Makes me think of HG, but might just be valve-related and oil cooler being bust, riiight...

Would I be able to spot the leak on HG through pressure-test?

[Doctor Gollum]

Oh yes

[oregad]

Oh yes

excellent, enough hope to start the process and find out the false hypostasis is a way to go.

[Marks DTM Calib]

Either way, oil in coolant is NOT head gasket 

[Migv6 le Frog Fan]

You need to find the source of the coolant leak. A mirror on a tick so you can see the rear of the engine can be helpful. Or pressurise with compressed air is even better.
After that, you definitely need a new oil cooler. And then lots and lots of flushing of the cooling system to get rid of the oil from it.

[oregad]

You need to find the source of the coolant leak. A mirror on a tick so you can see the rear of the engine can be helpful. Or pressurise with compressed air is even better.
After that, you definitely need a new oil cooler. And then lots and lots of flushing of the cooling system to get rid of the oil from it.

Yes, my plan is to take the plenum+DIS-pack off (to see what's happening), then pressurise, let us pray.

[Doctor Gollum]

You need to find the source of the coolant leak. A mirror on a tick so you can see the rear of the engine can be helpful. Or pressurise with compressed air is even better.
After that, you definitely need a new oil cooler. And then lots and lots of flushing of the cooling system to get rid of the oil from it.

Yes, my plan is to take the plenum+DIS-pack off (to see what's happening), then pressurise, let us pray.

Praying won't help.

If you have oil in the coolant AND a coolant leak where you describe, these are two separate problems.

Your best case is that the oil cooler has failed and the oil cooler cover plate is perforated.

A more productive list of parts to remove for proper inspection is the plenum, upper and lower intakes. That way you'll be able to see if the coolant is coming from the oil cooler cover plate or thermostat and draining out over the bellhousing. 

[oregad]

So a cross in the water and chanting ave maria wont fix it? 

Wondering if the weeping water would be intermittent if its the HG (seem unlikely doesnt it?)? Idled for 30 min and took a 10min drive around 1500rpm today just to ... I dont really know. But no lower coolant...

Realise I still most likely have a oil cooler leakage though. Would that mean the heat-exhanger is leaking, or just the sealant leaking (resulting in oily coolant water), i.g. should I prepare to replace the cooler instead of just cleaning it up and replace sealant.

Questions, questions.

[Doctor Gollum]

You misunderstood.

1. Failure of the cooler = oil in the coolant

2. Failure of the cover plate = coolant loss
2a. Failure of the head gasket as described = coolant loss
2b. Failure of the HBV = coolant loss.

1 is fixed by replacing the oil cooler (and flushing the cooling system with dishwasher tablets about 26 times.

2. Is not fixed with sealant. But rather replacing the porous aluminium plate with a new one. And maintain it by renewing the correct coolant every four years.

[oregad]

You misunderstood.

1. Failure of the cooler = oil in the coolant

2. Failure of the cover plate = coolant loss
2a. Failure of the head gasket as described = coolant loss
2b. Failure of the HBV = coolant loss.

1 is fixed by replacing the oil cooler (and flushing the cooling system with dishwasher tablets about 26 times.

2. Is not fixed with sealant. But rather replacing the porous aluminium plate with a new one. And maintain it by renewing the correct coolant every four years.

So, yes. New plate and oil cooler. Thanks.

[cam.in.head]

why were these engines designed with an oil cooler anyway in the first place.
is the engine stressed enough to need one ?

[Migv6 le Frog Fan]

In certain countries in certain circumstances - probably.
Imo, (based on no science whatsoever) I seriously doubt there would be any adverse affect to binning it on a UK car, unless you tow a huge caravan long distance every August .

[oregad]

Binning it means simply put, connecting the two unions together in the middle of the v (or removing and plugging from where the pipes should have been)?

It allways have a purpose, but I also doubt its function on normal drive (also, its ridicolously tiny, wouldnt function as a preheater for wvo-diesel)). Will search to replace it though. Wouldnt be fine finding it overheat at a long road away from home. But first I want it freed from problem.

Great thanks for the replies all. Strangely enough looking forward for some more wrench-friendly weather (longer days, less snow/mud, more sun) so I can start...

Any takers if intermittent leak can be HG? Leak been present for +6 months (of course I realize it can be, but putting it on a counter of probability).

[Doctor Gollum]

It allows the oil to warm the coolant more quickly in order to get the engine up to temp more quickly and reduce the cold idle times for emissions purposes.

Once upto temperature the cooling system maintains the overall engine temperature.

It isn't an oil cooler in the traditional sense, rather a liquid to liquid heat exchanger, although it could be modified to run through the radiator in cars with a separate trans cooler. (it's almost impossible to buy an Omega radiator without the trans cooler built in even though later cars are fitted with an external one. 

[TheBoy]

And intermittent coolant loss is far more likely to be HBV, and is easily checked visually.

But as you have to change the oil cooler anyway, you'd be radio rental not to change the cover plate.

Top tip when changing the oil cooler - do not bend the pipes.  Do it properly and undo the pipes near the oil filiter.  Bending them will stress them enough to cause them to leak at the oil filter end anyway, and also make them a complete arse to refit.  No need to ask how I know that, after I chose to ignore the good advice here

[oregad]

And intermittent coolant loss is far more likely to be HBV, and is easily checked visually.

But as you have to change the oil cooler anyway, you'd be radio rental not to change the cover plate.

Top tip when changing the oil cooler - do not bend the pipes.  Do it properly and undo the pipes near the oil filiter.  Bending them will stress them enough to cause them to leak at the oil filter end anyway, and also make them a complete arse to refit.  No need to ask how I know that, after I chose to ignore the good advice here

HBV is brand new (was spraying coolant like a mist), double-check and the engine watery just at the middle of the "v" when leaking.

Yeah Ove had my fair share of ruptured metal pipes.

[countrywoman]

The cover plate I had come with the stainless Vectra cooler was almost perforated through so good idea to get a new one.

[oregad]

Would a 3.2 cover work its magic? There are no 2.5 or 3.0 scrapped in Sweden.

[Doctor Gollum]

All exactly the same