[neil t]

Hi folks

My Laguna 1 has now topped 117,000 miles with few problems, 45 to the g etc but big G has dealt with my smugness.

Heard a pop last night, engine lost a bit of power and started missing. Found no.3 plug out of its thread, plug holder melted and smashed up. threads on plug and plug hole damaged. doesn't seem to be any other damage.

Any ideas of cost and possibility of helicoil refitted in situ?
appreciate ideas comments or sympathy

 

[scatz]

You have my sympathy!

Helicoil was my first thought but then I thought....it'd need to be drilled first which would mean metal filings in the cylinder

I dunno pal, beyond my abilities to advise really, hence the sympathy

 

[S80]

Hi - that's a bit of a bum*er

The other fly in the helicoil ointment might be access to the plug threads from the top of the head. The deep 'wells' may be a problem (that's for the 16V engine - not sure if that's the case here).

 

[madnoel10]

There is a special tap which has a hex end the same size as the spark plug so tapping the hole isn't the problem. Drilling is the difficulty - you would need either a long drill or drill extension.

There are two methods of preventing filings from entering the cylinder. One is to fill the flutes of the drill and tap with grease in the hope of any cuttings sticking and by careful slow drilling and constant cleaning you may be able to catch most of the swarf.

The other method involves using an air-line to pressurise the cylinder via an exhaust or inlet port causing any swarf to be ejected and extracted into a vacuum cleaner attachment.

Both methods are not totally risk free but the latter is the least risky.

There are specialist kits but sourcing a garage or engineering shop that has the facility may be the difficulty.