A lesson learned here on a simple job of replacing the spark plugs on my M271 engine
Due to the plugs being deep in the head, I had used an old tool to remove them - namely a short plug spanner with an extension tube secured with a couple of small self tappers.
I did not notice that one of the self tapper heads sheared off when removing one of the plugs.
When I started the car with the new platinum plugs, it sounded as though the bottom had fallen out of the engine - luckily I switched it off after about 2 seconds
Removed the plugs without having a clue what was wrong and noticed a couple of shiny spots on the top of no 3 piston and eventually noticed the missing screw head.
# Did a compression test to see if caught under a valve - good pressures - all OK
# Tried a Stanley magnetic probe fixed to a bit of flex wire - no good
# Tried probing the top of the piston (at BDC) with a stiff coat hanger (rounded end to not scratch anything and plastic tube to protect the plug threads in the head) - no good.
# Was then firmly convinced that the screw head was imbedded in the head beside one of the valves
# Got some heavy copper wire and twisted to get stiffness and folded two wires back so that it would open up like an umbrella and still be soft enough to pull out and not scratch the alloy head
# After many tries at scratching around to dislodge the screw head and following up with the magnet - out it came - Big smiles all round - would have been no car until 9th Jan when the dealer said they would be delighted to take $2000 from me for the 10hr job to remove and replace the head!
Two big lessons here
(1) Use the correct tools
(2) Be scrupulously clean and allow nothing to go near those plug holes
I feel extremely stupid about this and very lucky to have dodged a very inconvenient and expensive bullet!! - I hope the following pics will assist anybody unfortunate enough to experience a similar problem (quite common according to those dealers/mechanics I rang)
Oberoi
Due to the plugs being deep in the head, I had used an old tool to remove them - namely a short plug spanner with an extension tube secured with a couple of small self tappers.
I did not notice that one of the self tapper heads sheared off when removing one of the plugs.
When I started the car with the new platinum plugs, it sounded as though the bottom had fallen out of the engine - luckily I switched it off after about 2 seconds
Removed the plugs without having a clue what was wrong and noticed a couple of shiny spots on the top of no 3 piston and eventually noticed the missing screw head.
# Did a compression test to see if caught under a valve - good pressures - all OK
# Tried a Stanley magnetic probe fixed to a bit of flex wire - no good
# Tried probing the top of the piston (at BDC) with a stiff coat hanger (rounded end to not scratch anything and plastic tube to protect the plug threads in the head) - no good.
# Was then firmly convinced that the screw head was imbedded in the head beside one of the valves
# Got some heavy copper wire and twisted to get stiffness and folded two wires back so that it would open up like an umbrella and still be soft enough to pull out and not scratch the alloy head
# After many tries at scratching around to dislodge the screw head and following up with the magnet - out it came - Big smiles all round - would have been no car until 9th Jan when the dealer said they would be delighted to take $2000 from me for the 10hr job to remove and replace the head!
Two big lessons here
(1) Use the correct tools
(2) Be scrupulously clean and allow nothing to go near those plug holes
I feel extremely stupid about this and very lucky to have dodged a very inconvenient and expensive bullet!! - I hope the following pics will assist anybody unfortunate enough to experience a similar problem (quite common according to those dealers/mechanics I rang)
Oberoi