MrGorsky · Jan 25, 2016

Evening all,

My beautful V8 has developed a worrying sound! There is a clearly audable chuffing coming from the centre of the engine. If you remove the oil filler cap it gets louder, and is clearly coming from within.

Tick-over is steady.
Starts fine.
No steam of anything coming from the exhaust.
Can't really feel any pressuring of the crank case.
No smoke or fumes puffing out of the oil filler eith the cap removed.
Drives very well. No noticable loss of power or misfires.
No faults showing on the Nanocom.
It does use a bit of coolant, I've recently added UV dye, and still can't find the leak.

I've made a little recording of the sound (on the link) you can hear it very clearly. It disappears a bit when the engine is revved, but that might be it just getting lost in the other noise. The clicking you hear after I've revved it are the LPG injectors kicking in.

http://we.tl/8LBPWAijKI

Where do I go from here? It looks like Head Gasket failure doesn't it?

Grrrrrr · Jan 25, 2016

How about the exhaust manifold gasket? One of them anyway.

MrGorsky · Jan 25, 2016

Grrrrrr said:
How about the exhaust manifold gasket? One of them anyway.

Couldn't feel and draught coming from the manifold area. Didn't check too closely because of the increase in noise when I opened the oil filler. Seems to be coming from inside the engine to me.

Grrrrrr · Jan 25, 2016

Strip of paper in cleft of stick? Of course, need to be out of the wind to try it.

Grrrrrr · Jan 25, 2016

What does a slipping liner sound like? Any clips on Youtube?

MrGorsky · Jan 25, 2016

Grrrrrr said:
What does a slipping liner sound like? Any clips on Youtube?

More of a rapid clinking, like a metalic rattle. I've seen a video somewhere. I'm pretty sure it's not that.

Saint.V8 · Jan 25, 2016

Blocked breather??

MrGorsky · Jan 25, 2016

Saint.V8 said:
Blocked breather??

I can check it. That goes from the top of the rocker cover to the throttle body doesn't it?

Saint.V8 · Jan 25, 2016

MrGorsky · Jan 26, 2016

Saint.V8 said:
Yep!

Thanks Ant, but it seems clear so we can discount that.
I've always wanted to do a HG on a V8. It's probably a lot of fun. How are you getting on with your V8 rebuild? You don't fancy doing another do you?

biketeacherdave · Jan 26, 2016

ok so uv dye added no leak found now go pull your dip stick and see if that floureses thats how i finnally pinned down my head gasket failure

Falk · Jan 26, 2016

MrGorsky said:
Thanks Ant, but it seems clear so we can discount that.
I've always wanted to do a HG on a V8. It's probably a lot of fun. How are you getting on with your V8 rebuild? You don't fancy doing another do you?

Compression test.

Have you checked your intake side of it ?

All spark plugs done at same time ?

MrGorsky · Jan 26, 2016

Falk said:
Compression test.

Have you checked your intake side of it ?

All spark plugs done at same time ?

I haven't got the tools for a compression test, so I'll have to take it somewhere for that.

I haven't checked the intake side of it, and I have had the inlet manifold off in the last year to replace the valley gasket. Whats the best way to check it, soapy water and a spray gun?

All spark plugs were changed at the last service, Feb/March time I think. All looked in VGC, exactly what I'd expect to see in a healthy engine.

biketeacherdave, I'll check the UVness of the dipstick tonight....

Saint.V8 · Jan 26, 2016

Soapy water on the manifold won't show anything as on a petrol the manifold is a vacuum....

Brake cleaning fluid is pretty good....if the revs rise when sprayed on the joint, there is a leak....

A chuff chuff would be air escaping not sucking....so think exit side of the engine.

Maybe a stuck valve....whip the rockers off and check for anything untoward.

HG on a V8 is relatively straight forward, only pain is the exhaust manifold.

Oh and if you wanna borrow it, I have a compression Gauge somewhere!

Grrrrrr · Jan 26, 2016

MrGorsky said:
I haven't got the tools for a compression test, so I'll have to take it somewhere for that.

I haven't checked the intake side of it, and I have had the inlet manifold off in the last year to replace the valley gasket. Whats the best way to check it, soapy water and a spray gun?

All spark plugs were changed at the last service, Feb/March time I think. All looked in VGC, exactly what I'd expect to see in a healthy engine.

biketeacherdave, I'll check the UVness of the dipstick tonight....

I've got the ones for the diesel but can probably get an adapter to fit the petrol, although sensitivity might be an issue. Failing that I might be able to cadge one for a weekend. [EDIT: compression guage I was talking about.]

MrGorsky · Jan 26, 2016

biketeacherdave said:
ok so uv dye added no leak found now go pull your dip stick and see if that floureses thats how i finnally pinned down my head gasket failure

I have a glowing dip stick! And green dye under my oil filler cap too. Unless my oil has green UV dye in it for some reason, there's definitely coolant mixing with the oil.

MrGorsky · Jan 26, 2016

Saint.V8 said:
HG on a V8 is relatively straight forward, only pain is the exhaust manifold.

Do you know what the official name of the socket (they're star shaped aren't they?) I need to get the exhaust manifold studs off is? Might as well start collecting tools before I start!

Saint.V8 · Jan 26, 2016

Bi-Hex aren't they!!

No special tools required for HG job....aside for torque wrench and you may need an angular torque gauge.....

It is a simple job, just bolts, nuts and a few electrical connectors!

MrGorsky · Jan 26, 2016

Saint.V8 said:
Bi-Hex aren't they!!

If you say so Ant! I looked at them when I last had it all apart, they're pretty corroded... that's why thought they were some special star shape!
I do remember thinking "I hope I never have to tackle them" at the time.....

Saint.V8 · Jan 26, 2016

MrGorsky said:
If you say so Ant! I looked at them when I last had it all apart, they're pretty corroded... that's why thought they were some special star shape!
I do remember thinking "I hope I never have to tackle them" at the time.....

Plus Gas or another decent penetrating oil/release aid.....liberally applied, allow to soak in, apply again.....soak in......give them a slight turn, then re-apply and soak in

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