Symptoms of inlet manifold gasket leak.

[Bandit1200]

With negative result on compression gasses in coolant, can a failed inlet manifold gasket cause over pressurization of the cooling system?
If so, how is the pressure transferred and from where?
Thanks in advance.
Steve

[LD334]

Steve,
The normal issue seems to be that the coolant leakage reduces the static head on the original pump leading to cavitation, in turn circulation breaks down and the coolant boils in the block giving over pressurisation.
As you have just fitted an EWP low down that shouldn't happen, was the system fully bled? I added a small amount of flouricene (I bought from Amazon) to the coolant to make leaks easy to identify, if you do that and run your EWP the leak path will probably show up.

Paul

[Bandit1200]

Hi Paul
The system was fully bled and filled to full cooling system capacity of 10.5 L
I looked on Amazon for flouricene without success. Is this the correct spelling?
Thanks
Steve

[Steve JP]

I think this is what you're looking for

https://www.amazon.co.uk/d/5nr/Tools...ds=Flourascein

[flying farmer]

When you say over pressurisation, is it actually chucking water out of the expansion bottle, or hissing out of the filler of a header tank?

An inlet manifold leak will not cause pressurisation as it is below atmospheric pressure all the while the engine is running, the only way it could do it is by letting the water level drop inside the engine, then the extra volume of air being heated on engine start will cause trouble on the original expansion tank system, but on a header tank system you would only get a drop in water level and no trapped air.
You say you have put the correct amount of water in, but your electric pump system may have extra capacity due to the extra plumbing, so you could in fact still be airlocked.
Neil

Just realised from your electric water pump post that you have a header tank fitted, in that case it must be passing gas out of the filler when hot.

When the head gaskets failed on my stag engined TR, it hissed at me when I turned the engine off for the best part of a year before I fixed it, but never lost any water.

If it is still pressurising after your recent head gasket change I would suggest re torqueing it yet again.

[Bandit1200]

Many thanks for the responses.
Tomorrow it's carry out compression tests on each cylinder, check again for combustion gasses in coolant. (there never has been any) and order the fluorescein.
If no anomalies, I'll remove inlet manifold and refit with Wellseal and thin gaskets and retorque heads down to 60ftlbf and try again.

I'm sure I'm not the first to feel that a seemingly insurmountable problem will soon cure me of love for the Stag.

Best wishes
Steve

[davidf]

Many thanks for the responses.
Tomorrow it's carry out compression tests on each cylinder, check again for combustion gasses in coolant. (there never has been any) and order the fluorescein.
If no anomalies, I'll remove inlet manifold and refit with Wellseal and thin gaskets and retorque heads down to 60ftlbf and try again.

I'm sure I'm not the first to feel that a seemingly insurmountable problem will soon cure me of love for the Stag.

Best wishes
Steve

It is never insurmountable; it is just a challenge to prevent boredom setting in. And for that reason, you will still love your Stag in 30 years time!

[LD334]

I think this is what you're looking for

https://www.amazon.co.uk/d/5nr/Tools...ds=Flourascein

That's it, use sparingly as a full tub is enough to turn an Olympic sized swimming pool a very bright shade of yellow!

I suggest a dose of dye, a full system bleed, then run the engine to temperature and watching for leaks. If the inlet manifold is leaking slacken one head, tighten the manifold then retighten the head and repeat.

[Stagdad]

That's it, use sparingly as a full tub is enough to turn an Olympic sized swimming pool a very bright shade of yellow!

I suggest a dose of dye, a full system bleed, then run the engine to temperature and watching for leaks. If the inlet manifold is leaking slacken one head, tighten the manifold then retighten the head and repeat.

Unless the heads have been off recently i think they are unlikely to move but could well leak afterwards.I know the rom says to do this but i would think twice.I would dry fit the inlet with no gaskets and check all around it with feeler gauges to see if the surfaces sit parallel with the heads.

[Bandit1200]

I've carried out compression tests on all cylinders. Good consistent pressures with minimal differences.
Block test indicates no compression gasses in coolant.
Re torqued heads to 60ftlbf and tweaked inlet manifold bolts.
Added K-Seal.
Symptoms now gone and I'm a happy Stag driver again.
Thanks to all those who gave advice.
Best wishes
Steve