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[danzigfan]

Hi guys, my omega has always had some coolant missing, small amounts, nothing serious, but in latest month it became really strange.
Omega had heater core blocked so I did matrix flush and the heat is back. Job jobbed or so I thought...It developed a leak on lower heater hose fast clamp, so I cut plastic piece off and used hose clamp - success....not really...
it started leaking on HBV...replaced it and now it's dry as a bone....but leak transfered to radiator AUX pump, so I removed it and connected both radiator hoses together with a piece of steel pipe...And then leak transfered to fan switch on the top of lower radiator hose...
Strange thing is it only leaks a tiny bit when the engine is cooling down, not being hhot anymore.
What concerns me the most is, when the system is cold, next day after driving, coolant level is an inch low... if I open coolant bottle cap level rises close to max and a sound of pressure is released. Pressure in cold system makes me wonder if there is maybe head gasket problem....
Any help appreciated.
Thanks guys

[LC0112G]

You can buy head gasket test kits from eBay for not very much...
https://www.ebay.co.uk/itm/284004648824

They're easy to use, and will detect any combustion gasses that end up in the water. The coloured dye starts off blue, and will turn yellow if there are combustion gasses present, like this...

https://www.omegaowners.com/forum/index.php?topic=148724.msg1988834#msg1988834

If the dye goes yellow, then you can be pretty certain you've got a head gasket problem.

[TheBoy]

Fire ring failure on the v6 is very rare, but certainly no harm in testing, either by smelling for fumes in the coolant tank, or one of the test kits as mentioned above, or get your local garage to use their tester.

[danzigfan]

Thanks, will give a try

[cam.in.head]

also worth trying a new cap in case either of the valves are stuck ?

[countrywoman]

I would say cap first. Sniffer test as well.

[Nick W]

Head gasket replacement is a lot of work, and money in parts. Consequently, you need to be sure it's the problem.


That means spending some time, and probably money, on proper diagnosis.


The chemicals that check for combustion gases in the coolant are probably the place to start as they're quick, cheap and easy to use without any dismantling.


I'd do a pressure check on the cooling system for similar reasons, although you need to remove the spark plugs and check the bores with a camera to be thorough.


A leak down test is the definitive method, but requires some costly kit and a lot of time - you could probably lift the heads off a Ford OHV V6 in the time to do this test on an X30.


My 3.0l exhibited similar symptoms, in that it only lost water after switching off, but briefly produced noticeable steam from the exhaust when restarted from cold. The cause was failure of the gasket at rear of the RH cylinder head, although the LH one wasn't much better - that cylinder was cleaner than the other two, unlike the RH which looked like it had been steam cleaned.

[Doctor Gollum]

Weren't the 2.5 and 3.0 of certain year prone to failure of the back of the 246 gasket

[YZ250]

Weren't the 2.5 and 3.0 of certain year prone to failure of the back of the 246 gasket

My 98 MY certainly was. The rear corner of the 246 bank gasket rotted outwards, causing a slight coolant leak on cool down. As previously mentioned, the fire rings were fine. The heat from the engine evaporated the coolant leak, making it difficult to find initially. It left a slight water mark just under the cylinder head rear corner. 

[danzigfan]

I ordered a "sniff" tester today, I hope it's not a head gasket but I have a sneaky susspission it could be...I don't know what else to do...It would be a shame to scrap it, after all this work and money I've put into it. Really shame...
And there is absolutely no other car that I like, nothing to replace it after more than 15 years of omega ownership.
So it will probably go for a rebuild if it happens to be a head gasket

[TheBoy]

Weren't the 2.5 and 3.0 of certain year prone to failure of the back of the 246 gasket

Early 98MY 3.0l (built in 1997) were prone to a HG failure allowing coolant to escape at the back of pot 6.  That particularly failure causes no other symptoms aside from coolant loss and associated steam.

[danzigfan]

..some update. Link to video is added...
 https://youtube.com/shorts/lOiYNaOll_Q?si=Tv7OXVxt-ATjv8NZ
https://youtube.com/shorts/Pfc05T5GOmY?si=YGJrnpdMnYUDnDgd

...I'm not in a good mood🙄

[biggriffin]

Weren't the 2.5 and 3.0 of certain year prone to failure of the back of the 246 gasket

Early 98MY 3.0l (built in 1997) were prone to a HG failure allowing coolant to escape at the back of pot 6.  That particularly failure causes no other symptoms aside from coolant loss and associated steam.

 I've done a few 3.0L head gaskets,  as was stated back cylinders on both banks,.

[JamesV6CDX]

Weren't the 2.5 and 3.0 of certain year prone to failure of the back of the 246 gasket

Early 98MY 3.0l (built in 1997) were prone to a HG failure allowing coolant to escape at the back of pot 6.  That particularly failure causes no other symptoms aside from coolant loss and associated steam.

 I've done a few 3.0L head gaskets,  as was stated back cylinders on both banks,.

Interesting observation there. I too have seen 3.0 failures but only ever on pot 6.

I’ve never seen it at the back of the 1-3-5 bank. Not doubting you at all, just sharing my exoerience

[olm]

Weren't the 2.5 and 3.0 of certain year prone to failure of the back of the 246 gasket

My 98 MY certainly was. The rear corner of the 246 bank gasket rotted outwards, causing a slight coolant leak on cool down. As previously mentioned, the fire rings were fine. The heat from the engine evaporated the coolant leak, making it difficult to find initially. It left a slight water mark just under the cylinder head rear corner. 

It happened to me too! I'm surprised that it broke from the outside in until it attacked the ring, I thought it was a bad purge on the part of the LPG installer, but I see that it is common.

[Doctor Gollum]

MarkDTM did explain how/why it fails without mixing oil. Something to do with where the oil and coolant galleries are in the engine. It's one of the few engines where it will run indefinitely as long as you keep it topped up with water.

[Nick W]

Mine was leaking coolant into the driver's side rear cylinder, once the engine was turned off due to a rotten gasket. No other symptoms other than a slow but persistent water loss and a steam cleaned spark plug.


The passenger side gasket didn't look any better, but wasn't leaking.