Hele-coiled spark plugs

[Captain Bongo]

Hi - Dull as dish water issue for you.

I have had 2 spark plugs blow out of the cylinder head on a 90k mile Mk1 Ford Focus. This happened within 2000 miles of each other and roughly 3 months after a full service. I am guessing that the spark plugs were done up too tight which buggered the thread.

On both occasions the car was towed to a local garage and they used heli-coils to get the spark plugs back in.

The car is worth peanuts and we only really use it when we need to take the dog out, but my concern is that one of the other two threads fail when in a dodgy spot (or when the mrs is driving alone). So do you think it's worth hele-coiling in the remaining two spark plugs or am I looking at a new cylinder head (guessing a couple of hundred quid)? I don't know if a hele-coil is a plaster or a more long term fix.

Cheers in advance.

[paintman]

Properly done helicoil is fine.

[Boosted LS1]

If you're concerned then get somebody to look at the remaining threads and then decide. Helicoils aren't expensive if you need to make a repair.

[Evoluzione]

Get somebody to check the condition of them first.
A Stainless steel thread insert is stronger than a 'normal' original thread in aluminium, many aluminium parts come with them already fitted.

[ian_uk1975]

Agree with all the above. You can easily install the Helicoils yourself (head off, obviously) for just a few quid.