What to do........

[Little Red Car]

Hi all

Just confirmed with a block tester that head gasket has gone, I suspected it had as the cooling system was pressurising. It has been like it for some time and will use a about half a pint every time I go out and the engine gets to full working temperature. The gauge hovers just over the midway mark and it only starts to go up if I stay at a constant speed on a motorway or dual carriage way for example, so I don’t do that!

The question is what if any damage will I do, if I continue using it like it is? I have to top it up every time I use it but I’ve got used to doing that. I don’t really want to miss the summer but on the other hand I don’t want to cause any irreparable damage.

The next problem I have is that I know the PO skimmed the heads by 70 thou, can I skim them any more? Would I need shims and what are people’s experiences with them? I must say I’m tempted with a couple of heads from Tony Hart as a ‘quick’ solution……


Keith

[Nambo]

Wouldn't that water getting in the combustion chamber possibly cause rust damage necessitating a rebore?
I also understand that hot pressurised gasses being forced through the small gap your failed head gasket offers, might damage further the alloy cylinder head face requiring an even deeper skim.

[flying farmer]

As a carry on using it measure you can fit a header tank, I did about 5000 miles with a pressurising cooling system and left it to Winter to sort out.

A header tank allows the gasses to escape without blowing water out unlike the standard system.

First I would try re torquing the head bolts, if they have not been done for a while they may be suprisingly slack and this may solve the problem. Slacken each one by a flat before retorquing.

Water does not generally get into the cylinders from the head gasket, usually inlet manifold gaskets.

It is quite possible for the head gaskets to fatigue fail without any damage to head or block provided it is not allowed to overheat, I had this happen after about 70,000 miles on one engine.

Neil

[jleyton]

A header tank allows the gasses to escape without blowing water out unlike the standard system.
Neil

Hi Neil,

That's very interesting. Why is that ?

Cheers

Julian

Ps Please don't get me wrong - I don't doubt what you say, I'm just intrigued as to why a header tank should make a difference.

[grumpy2]

The symptoms you describe are very similar to mine, I also had a misfire when starting from cold. I reasoned that this was due to hot pressurised water seeping through the gasket into cylinders 4 and 8 during cooling. Then on startup the water had to be ejected before combustion could occur. I confirmed the water theory by inserting a paper towel through the plug hole when the engine was cold and it came out wet and smelling of carbon and antifreeze.

Gary

[Nambo]

Water does not generally get into the cylinders from the head gasket, usually inlet manifold gaskets.

Neil

So where would his missing water be going?
I would have thought on every induction stroke, water would be sucked in from an already pressurized system, whilst possibly not damaging a hot engine, when the car is cold and not running, wouldn't water still leak in to rust those bores?

When I previously rebuilt my engine, one of the bores had signs of rust stains, fortunately removable by a hone.

[Little Red Car]

Some interesting points made here!

When the car starts cold or hot I have never seem any signs (i.e. white smoke) that there is water in the bores. I have always assumed that as the water system was being pressurised further than it should be the water was being pushed out the overflow....... I don't remember it ever missfiring either.

I can see the logic of the header tank conversion, it has never seemed right that the overflow should be at a lower level than the radiator and I had always intended to fit one, I will be doing it sooner rather than later and checking the torque of the cylinder head bolts!!



Keith

[Stagsongas]

I think I'm correct in assuming that an 8 cylinder engine only ever stops in one of 4 positions ( 4 cylinder, 2 positions, 6 cylinder 3 positions)

If that is the case, it may be that your engine stops with the leaking cylinder(s) on compression or with either valve open (only atmospheric pressure in the cylinder) but not on induction, with no low pressure and hence no coolant ingress.

It may also be that coolant is only being inducted whilst the engine is running (with manifold depression) which might point to an inlet manifold gasket failure rather than a head gasket failure?

Good Luck

Steve

[richardthestag]

A header tank allows the gasses to escape without blowing water out unlike the standard system.

Sorry but i do not agree, recent hgf on my stag v8 and extensive hgf issues which turned out to be slipped liner on my last Range Rover V8 both displayed exactly the same issues. I guess it depends on how badly the head gasket has gone.

At the risk of an essay, my findings are as follows.

Both have a nice big header tank and installed above the top point of the cooling system.

In both cases cooling system over pressurisation caused the excess to be released by the cap on top of the header tank. On both you could tell when this happened as you got a nice healthy whiff of coolant while driving along.

Neither showed any sign of overheating at all. Both drove very well. Although the last few weeks of the range rovers life it suffered from chronic misfire and despite head gasket replacement. Different story.

When the low coolant light comes on, indicating .5 litres has been dispensed with in the above fashion i would stop. Both tv8 and rv8 took 30-40 miles of motorway driving. My stag had a see thru header tank and i could see that it was about 1/4 full. Wait 10 mins or so and then very carefully release whatever was left of the pressure. I used a large lump of carpet over the top of the cap before slightly releasing the cap. Probably lost another 2 litres or so of coolant out of the still hot system before all pressure was released and i could safely remove the cap.

Continual excess pressure caused the Range rover to pop a plug on top of the rad, defied gravity and spat all its coolant upwards and into the atmosphere while on the m40 at speed. In the time it took me to pull over from outside lane to hard shoulder the temp gauge dropped to nowt and then started to climb again. I didn't have to worry about switching the engine off as it simply stalled and seized at the same time. It did release and actually start once it had cooled but the engine was a goner.

Rv8 can take some horrific punishment and still run.

I tried k-seal in the rv8 and it lasted 12k or so. Became part of an annual top up. But eventually the problem got so bad that it led to catastrophic failure. I had the heads off, did gaskets and skimmed heads etc. k-seal in the stag made no difference at all.

Header tank and level switch on the stag saved me from almost certain overheating on my most recent trip. It also allowed me to limp the car home by stopping when ever the low coolant light came on. Without either of those the first i would have known about hgf would have been steam and a broken engine.

[Jeff]

Sorry but i do not agree, recent hgf on my stag v8 and extensive hgf issues which turned out to be slipped liner on my last Range Rover V8 both displayed exactly the same issues. I guess it depends on how badly the head gasket has gone.

At the risk of an essay, my findings are as follows.

Both have a nice big header tank and installed above the top point of the cooling system.

In both cases cooling system over pressurisation caused the excess to be released by the cap on top of the header tank. On both you could tell when this happened as you got a nice healthy whiff of coolant while driving along.

Neither showed any sign of overheating at all. Both drove very well. Although the last few weeks of the range rovers life it suffered from chronic misfire and despite head gasket replacement. Different story.

When the low coolant light comes on, indicating .5 litres has been dispensed with in the above fashion i would stop. Both tv8 and rv8 took 30-40 miles of motorway driving. My stag had a see thru header tank and i could see that it was about 1/4 full. Wait 10 mins or so and then very carefully release whatever was left of the pressure. I used a large lump of carpet over the top of the cap before slightly releasing the cap. Probably lost another 2 litres or so of coolant out of the still hot system before all pressure was released and i could safely remove the cap.

Continual excess pressure caused the Range rover to pop a plug on top of the rad, defied gravity and spat all its coolant upwards and into the atmosphere while on the m40 at speed. In the time it took me to pull over from outside lane to hard shoulder the temp gauge dropped to nowt and then started to climb again. I didn't have to worry about switching the engine off as it simply stalled and seized at the same time. It did release and actually start once it had cooled but the engine was a goner.

Rv8 can take some horrific punishment and still run.

I tried k-seal in the rv8 and it lasted 12k or so. Became part of an annual top up. But eventually the problem got so bad that it led to catastrophic failure. I had the heads off, did gaskets and skimmed heads etc. k-seal in the stag made no difference at all.

Header tank and level switch on the stag saved me from almost certain overheating on my most recent trip. It also allowed me to limp the car home by stopping when ever the low coolant light came on. Without either of those the first i would have known about hgf would have been steam and a broken engine.

Have to agree, with my original header tank fitted, pressurised coolant used to poor out of the cap and head gaskets were found to be gone.

My daily had a very small leak in the rad a short while ago and K seal did nothing at all so had to have a new rad, despite wonderful reports on the stuff.

Jeff.