Head gasket leaking?

[Chris Ivin]

I was checking the cylinder heads nuts as it had been 18 months since I reconned the engine. When setting the tappets after checking the head nuts(only one tightened very slightly) I noticed that gas was bubbling trough the threads of the two centre most studs!

Does this indicate that the head gasket is leaking (probably a silly question)

I have had her overheat a couple of occasions and have just had the radiator recored, I guess that the damage was done already! There is no sign of oil in the coolant or water in the oil, I wouldn't even had known if I hadn't got the rocker cover off.

[Jan 59]

Yes possible ,these studs are close to the cylinderwall.
Did you run your reconned engine for an hour and retorqued head nuts after that time with the engine still hot? Its also recommended to loosen cylinderheadnuts slightly before retorqing.
Did you coat the gasket with sealer? (Ford says that it is neccesary)
I did mine with Rolls Royce Hylomar and its perfectly tight.

If there is oil in the cavity between head bore and stud it may cause bubbling at the nuts. Suggest run engine with radiator filled to top and run engine .
If head leaks also in cooling system water will bubble up.

Regarding overheating this is very uncommon unless faulty waterpump or radiator . I use my dexta with a 7ft rotary orchard mower and that's hard work, sometimes the engine lugs down about 500 revs but temp. gauge stays in green area. and the fan is only 2 blade.

[Chris Ivin]

Yes I did coat the gasket with sealer. I also retorqued after running for about half an hour.

I will check the radiator as you suggest.

I must admit that I knew that the radiator wasn't 100%, it had some filler in places where leaks had been stopped. I was OK 99% of the time only very occasionally causing a problem e.g. running a 1.8 metre flail mower in tall grass(once only).

As i said I only noticed the symptoms because I took the opportunity to check the tightness of the head nuts while I was fitting the recored radiator. Otherwise I would still be none the wiser.

I am unsure whether to leave it for the time being and keep an eye on the water and oil or whether to dive in and change the head gasket?

[Brian]

Leave it Chris. The only time to worry is when it leaks into the oil, the radiator or bore. She will tell you when you have a problem with white smoke or bubbles in the radiator.

[Chris Ivin]

Thanks Brian,

I'll leave it and keep a close eye on the water and oil.

At least she shouldn't overheat now the radiator is fixed.