|
Any suggestions welcomed on how to free a seized spark plug in a 309 GTI before bowing to the inevitable new cylinder head. Garage noticed the seized plug when my daughter's car was being serviced and left it in a small pool of releasing fluid for a couple of weeks. Yesterday the fluid was still there and the plug still wouldn't budge and the only thing they can suggest is to try after a hard run when the engine is very hot. Unfortunately, I am 5,000 miles away and don't know what the garage uses for releasing fluid. Anyone got any last resort suggestions?
|
|
Before trying anything with a chemical action, the obvious thing is WD40, which is first and foremost a penetrating fluid like paraffin. If the plug won't release after giving the warm plug recess a soaking in WD40, drastic means must be needed.
|
Ah! Routine problem with some small Ford engines I think, so the boys who have dealt with them may be along shortly.
I would tend to sparingly and often apply materials specifically marketed as penetrating oil or releasing oil. My favorite is "plus gas". It may be possible to use epoxy or similar to make sure it doesn't drain away (not sure of the head shape/design). Best applied when the thing is parked up for the night.
When you make the final attempt, best to make allowances should the thing snap off, and be prepared to take the head off and take it to a specialist for a helicoil (or even a new head)
Alternatively, just ignore the thing until it gets to the point where the plug causes a consistent misfire. You may be surprised how long plugs can last
|
If Plus Gas (good stuff) doesn't work:
I used to change the interference fit iron liners in my alloy kart racing engine barrels, and the main bearings in the alloy crank cases, by placing the assembly in the oven, whilst the new components (liner or bearing) spend a short spell in the deep freeze.
I lived at home in these years past, and Mum used to go Ape, but it worked a treat. Easy peasy every time.
Obviously the freezer bit doesn't apply to you, but I would still consider an industrial oven (to get the size) as a uniform, controlled, heat source to expand the head (The alloy will expand more than the spark plug). I would be too much of a coward to risk localised heating such as from a blow torch, as you want the head to seal afterwards, and doubt that taking the car for a run will get it hot enough.
|
Yup
I realise my suggestion re epoxy may be misleading. I meant you should apply 2-3mm in a thin bead around the plughole if possible, so as to make a shallow "bath" in which the Plus Gas can lie instead of draining away. Beware, If you try and use a flame on it it may ignite. Should be OK if the engine runs up to temperature though
The reason I suggest preparing to take it to an engineer's is that if the thing is really stuck it can snap off, or take the thread out of the head as it unscrews.
You will then need a helicoil, large oven, drill press etc, and you don't want to be researching that on a Sunday afternoon.
|
It's not common for a steel plug to seize in a alloy head.
Sure it's not cross threaded ? In either case, when the plug is removed the thread in the head is likely to come out with it. Trying to remove with the engine hot is the best bet, but be prepared for at least a helicoil insert. If the plug hole is accessible it should be possible to fit an insert without removing the head.
|
Should have mentioned in the first post, but forgot.
If the sealing gasket or taper on the plug seat is working correctly, penetrating fluids won't be able to reach the thread.
|
|
|
