Possible head gasket failure

[KSM62]

Hi all. I am Keith from Bristol and joined the SOC early last year when I acquired my first Stag from an ex SOC member in Wales. Its a 77k one owner manual with a hard top in need of some general tidying and improvements. I ran it until September when the MOT ran out and I took it off the road to do some body and mechanical work prior to getting it MOT'd. A couple of month later I started the car to be met with clouds of white smoke from the exhaust. I have done both a leak down test and compression test but haven't got any conclusive results that indicate head gasket failure. One thing that bothers me though, is that there is a fluid residue in the inlet manifold. It smells and feels more like oil than fuel. Surely this cant be right? I spoke to the previous owner today and he assures me that the heads have never been off the car so if it is a failed head gasket its unlikely to be a easy job to get them off.

Keith

inlet_manifold.jpg

[GDPR]

Hi Keith and welcome.

That residue is not anything to do with heads, just some condensate from fuel. Your clouds of steam could be an inlet manifold gasket or heads - sometimes you can get an indication of where by discolouration of the sparkplug on the affected cylinder/cylinders.

The fact that the heads have never been off doesn't bode that well though....

Good luck with it, there is plenty of good advice available on here

Russ

[KSM62]

Thanks for clearing that one up Russ. I have had the inlet manifold off and replaced with quality gaskets so it looks like my only option now will be to take the heads off. I've done a few head gaskets in my time but never a V8. I'll see how far I can get but if I get totally stuck my local classic car restorers in Bristol, Auto Classico, should be able to finish the job off at a price.

Keith

[HersnotHis]

Thanks for clearing that one up Russ. I have had the inlet manifold off and replaced with quality gaskets so it looks like my only option now will be to take the heads off. I've done a few head gaskets in my time but never a V8. I'll see how far I can get but if I get totally stuck my local classic car restorers in Bristol, Auto Classico, should be able to finish the job off at a price.

Keith

Don't jump in without further careful checking/examination as indicated by KRYTEN.

On a cold day our Stag on full choke issues volumes of white smoke - actually steam! When it warms up and preferably driven for a mile or so the exhaust is clear.

Please double check before removing heads

H

[wilf]

Was it a cold winter day when you started it up? It is pretty normal to see clouds of condensate until the engine is warmed through under those circumstances. Mine certainly does it but stops once it is warmed through, and I have never worried about HGF, as it is just "normal" for an old car. Even my modern daily drive does it to a degree.

Does your cooling system pressurise or lose coolant? Is one or more cylinders "steam cleaned" of carbon deposits"? If no to both of those, maybe reconsider the diagnosis.

Just always looking for the "easy fix" myself. Or "no fix" if it isn't needed.

[mole42]

Hi Keith,
Bring it around to me if you want a second opinion, I'm near Westbury-on-Trym.
I did my heads a year ago.

Richard

[Stagdad]

Thanks for clearing that one up Russ. I have had the inlet manifold off and replaced with quality gaskets so it looks like my only option now will be to take the heads off. I've done a few head gaskets in my time but never a V8. I'll see how far I can get but if I get totally stuck my local classic car restorers in Bristol, Auto Classico, should be able to finish the job off at a price.

Keith

It's not uncommon to get trouble sealing the inlet even with quality gaskets, I wouldn't rule it out even if you have just done them.

[Tdm]

Quite a few years ago now I replaced my Inlet Manifold with a reconditioned one from Paddocks during a HG change,
and that was 12 years ago now, and (touch wood) have had no problems with the Heads since.

[LD334]

Leak tight joints require the gaskets to be evenly compressed by the securing bolts, ok that's obvious, but you are bolting a very stiff piece of metal between two even stiffer pieces. If one side of the manifold is set tight to its head, torquing the bolts on the other side doesn't generate nearly as much clamping force on the gasket as the manifold will be very slightly off centre.
The Repair and Operations Manual says to slacken off one head, make up the manifold bolts, then retighten the head but that's better on paper than in practice given how tight heads can be stuck. I used lots of Hylomar and built up the torque gradually and evenly on both sides.

[flying farmer]

Was there more white smoke from one exhaust than the other?

Normally a leaking inlet manifold will cause more smoke on the affected side, though some can transfer between exhausts via the balance pipe. A very small leak usually shows up worse after a long time standing, simply due to more time for water to leak into the inlet manifold. The cylinders affected are the rear two on both sides due to the proximity of the large waterway. Inlet manifolds can be a PITA to seal properly due to the face becoming warped.
I recently rebuilt a mates Stag engine and had to spend an hour with a block of flat metal and some Emery cloth to remove the banana like bend in the mounting faces.
Neil

Head gasket failure more often causes cooling system pressurisation than white smoke as it is easier to pass gas at high pressure into the cooling system than water at low pressure into the cylinder.
Personally I would leave well alone until you have run it some more just in case it is only condensation. All my Stag engine cars chuck out clouds of white smoke on cold mornings.

[Guest]

You are lucky.
On Jaguar V12 E types it's usually clouds of blue and black smoke!

White smoke and steam are usually more like early 19th century industrial revolution stuff, - typical old fashioned black & white tech...the image equivalent of silent films.

It took Jaguar of Coventry until the 1980s to go to full colour glory with lots of loud noise to go with it. Took 3x more fuel mind you...

[KSM62]

Hi all, back again

All good info from the collective. The car currently doesn't have an MOT and it was while it was at the testing station in November that the extent of the problem became obvious. My initial thoughts on the day of the test were that the grey smoke would clear once it was fully warmed up. I used to experience the same on a 86 500SL but that always cleared after about 10 mins. However the testing station had it running all morning and it never reduced enough for them to be able to do an emissions test.

My early investigations showed even smoke from both pipes and the odd bubble appearing in the expansion bottle. However I was not able to replicate this with a leak down test. There was moisture in the V but this was also contaminated by a leaking carb. When I refitted the inlet manifold I did so with quality thick gaskets and plenty of Hylomar. I also Helicoiled with 7/16 inserts the long inlet manifold bolts as one stripped removing the bolt and another felt it was going. The manifold was pulled down evenly and gradually. Once everything was back in place I ran the engine for about 20 mins but still had the same volume of white smoke.

I had actually already started the process of removing the heads before reading these posts and have removed all the lower bolts and two from the NS bank above 2 and 4. The other 3 wouldn't budge with the extraction tool. Currently soaking everything in easing fluid. I'll hold off til tomorrow to see if anyone has any other thoughts - long weekend booked off - but I don't think this is a problem of condensation.

Keith

77 Triumph Stag
78 VW T2 Bay window
71 Triumph Herald 13/60
02 Rover 75 CDT Tourer

[GDPR]

Sounds like you need to get your paws on some head jacking bars and an air chisel with a shortened blunt end tool to shock the studs. You did miss an old trick of mine to drain the coolant and run the engine up to temp, then attack the studs immediately - the ally of the head expands slightly and can relinquish its grip on the studs while it's still hot.

I will say I've never yet had a head that I haven't been able to remove without damage (famous last words) - 4 so far this year - so it can be done, just needs patience and care if you need to cut the studs

Good luck

Russ

[KSM62]

Hi Russ. I do have an air chisel and have read that you can use bottle jacks but I am not familiar with the technique. Can you elaborate. I haven't disturbed the heads yet other than removing the lower bolts and a couple of studs over 2 and 4.

[Tdm]

I wonder if there are any Stags around that have not had a Head Gasket change at all in their life?

I am only the 2nd owner of my Stag and have all the repair bills from the 1st owner who between 1978 and 1994 when I bought the car didn't suffer a HG failure. During my own ownership of the car I have done 2 Head Gasket changes, but the reason for the 2nd one in 2005 was that I obviously didn't do a particularly good job on the 1st one 7 years previously.

I don't expect to have to do another one unless I have a catastrophic failure of something like the jackshaft or the timing chains (which I changed some years ago), and the crankshaft was replaced in 2003, so that should be O.K.

The engine is sounding and running well at the moment (fingers crossed), and Tenerife is only a small Island so I don't do a lot of miles in the car, but it is my only car and it gets used every week I am at home in Tenerife.