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[Webby the Bear]

Thing is mate, if it turns out to be the HG (which I really doubt from all that's been said) consider that there's a massive positive to take from it: you get to renew loads of seals 'n' gaskets.... exhaust fanny-mould's, cam seals, the HG's themselves, lifters, stat, re-seal or replace oil cooler, cam covers, timing belt kit, aux belt. Could also take the opportunity to upgrade to 3L camshafts.

 

[Webby the Bear]

Ps, Taxi...

I presume where the HGs fail isn't just the back of the 246 head and could happen to the back of the 135 head? if so how on earth would you check for this? I suppose you could get ya hand at the back of the 135 but impossible on the246 bank 

[chrisgixer]

If the hg had failed internally, there would be water in the oil and Mayo ON THE DIP STICK. Ignore mayo on the filler cap, that's purely a sign of short journeys and the engine not getting quite hot enough to warm the extended filler neck which sits in colder air. To disprove that symptom, remove the filler neck and fit the oil cap in its place. No more mayo. The neck is there purely to aid filling of the v6 engine on rear wheel drive applications.

If the hg has failed externally then the compression test would read normally.

You need to pressure test the cooling system to find the water leak, having tested the hbv with engine running with ac on hi and then on low, or vice versa, while getting a hand on it to feel for (hot) water.

Oil leak, likely cam cover gaskets. There is very little chance of oil leaking from the hg, with only one oil way on the high side of the v, so that would be evident from the pressure test if done with plenum and inlet manifold etc removed.

IMO, ignore the hg concerns, and concentrate on the individual symptoms of oil and water loss. Certainly get in touch with Guffer to get eyes on.

[chrisgixer]

How much oil /water loss are we talking?

Core plug on the 246 bank head is not unknown. Although 99 year hg's do seam to fail externally.

Search the site for oil and water leaks though.

[Webby the Bear]

Sorry Chris, all this talk of HG is me hijacking 

I can be a stoopid bear sometimes..... pressure test to find the rear HG leak. Why didn't I think of that 

[Webby the Bear]

Ps, whilst pressure testing.... if i wanted to check the back of the heads whilst systems under pressure is viewing best with a torch from underneath? Can you even see the backs of the heads from underneath?

[Nick W]

Ps, whilst pressure testing.... if i wanted to check the back of the heads whilst systems under pressure is viewing best with a torch from underneath? Can you even see the backs of the heads from underneath?

Sort of. What you want for that is a mirror on a stick.

[Webby the Bear]

Ps, whilst pressure testing.... if i wanted to check the back of the heads whilst systems under pressure is viewing best with a torch from underneath? Can you even see the backs of the heads from underneath?

Sort of. What you want for that is a mirror on a stick.

Cheers Nick 

[Webby the Bear]

PPS, sorry one last question... how long should it hold the 15psi (roughly) pressure for to know that there's defo no leaks?

[Rods2]

When I had head gasket go on my 3l it was on pot 6 and the fire ring had corroded so it was leaking. I suspect that cylinder 6 runs the hottest and is the most prone to go. As you the lowest compression on this cylinder on your test, so it maybe suspect. I also made a coolant pressure testing cap as per the maintenance guide, which showed the system would not hold pressure. I could also smell exhaust fumes being released via the coolant system with the expansion cap top off and on a hot day with a hot engine I was still getting steam which smelt slightly of anti-freeze.

Personally, I would double and triple check to be absolutely certain as it is not cheap parts wise to replace the head gaskets, if it proves unnecessary. I would not recommend running it for sometime like I did when I suspected the head gasket as I had slight pitting on the alloy head which meant I had to have the heads skimmed.

[Gaffers]

Ok I had a bit of spare time this evening and popped over for a look.

Results were:

- coolant, clear.
- oil in plugwells present due to previous mechanic not cleaning the breathers and using pattern gaskets.
- recent change of hbv pipes due to them being the wrong way around.  Noticed a little coolant drop on the very bottom hose clip.  Tightened it up a little more but to keep an eye on in case of early hbv failure.
- engine runs smooth, no excess moisture at exhaust, no air bubbles of note in the coolant system and it heats up normally.
- no coolant leaks noticed underneath the engine bay.

Diagnosis:

Hbv pipe was slightly loose causing slow and gradual leak.  Potentially some leakage by the oil cooler plate but this can be inspected when the rocker gaskets are replaced. Not convinced there is a leak there though as no evaporation noticed once the engine was hot.

In all a nice motor

[05omegav6]

Good stuff

Gaskets and Hbv are easy fixes much better prognosis that head gasket failure...

[Gaffers]

Yup, an easy fix and as usual just fixing the crap work of shoddy mechanics

Follow the guides Steve and you will be fine ;-)

[kevinp58]

Ok I had a bit of spare time this evening and popped over for a look.

Results were:

- coolant, clear.
- oil in plugwells present due to previous mechanic not cleaning the breathers and using pattern gaskets.
- recent change of hbv pipes due to them being the wrong way around.  Noticed a little coolant drop on the very bottom hose clip.  Tightened it up a little more but to keep an eye on in case of early hbv failure.
- engine runs smooth, no excess moisture at exhaust, no air bubbles of note in the coolant system and it heats up normally.
- no coolant leaks noticed underneath the engine bay.

Diagnosis:

Hbv pipe was slightly loose causing slow and gradual leak.  Potentially some leakage by the oil cooler plate but this can be inspected when the rocker gaskets are replaced. Not convinced there is a leak there though as no evaporation noticed once the engine was hot.

In all a nice motor

 

[Rods2]

Ok I had a bit of spare time this evening and popped over for a look.

Results were:

- coolant, clear.
- oil in plugwells present due to previous mechanic not cleaning the breathers and using pattern gaskets.
- recent change of hbv pipes due to them being the wrong way around.  Noticed a little coolant drop on the very bottom hose clip.  Tightened it up a little more but to keep an eye on in case of early hbv failure.
- engine runs smooth, no excess moisture at exhaust, no air bubbles of note in the coolant system and it heats up normally.
- no coolant leaks noticed underneath the engine bay.

Diagnosis:

Hbv pipe was slightly loose causing slow and gradual leak.  Potentially some leakage by the oil cooler plate but this can be inspected when the rocker gaskets are replaced. Not convinced there is a leak there though as no evaporation noticed once the engine was hot.

In all a nice motor

Well done.