Originally Posted By: djb
You didn't mention the engine.
I'm assuming that you are talking about a coil-on-plug configuration with a spark plug that sits in a well. There is a "connector" on the bottom of the coil that's essentially a spark plug boot.
The geometry of 3+ valves per cylinder pretty much constrains the plugs to sit in a deep well. Typically the valve cover has individual spark plug seals. Any leak causes oil to gather in the well, with no place to drain.
The oil doesn't cause any direct problem. It is electrically non-conductive, and a good thermal conductor. But over time the additives soften the rubber, making the connector prone to splitting.
Once split, the connector is very likely to cause a misfire that's similar to a bad plug wire. Not right away, but a week or two later after a carbon track builds up from minor discharges that don't initially cause a misfire.
If you replace the valve cover gasket and clean the connectors off before they start splitting, they usually will be serviceable. It's normal for them to ooze oil for a while, most from the conductive core and a trivial amount that has soaked into the rubber. If they haven't split, just clean them off.
The coils can split from the oil? Oh great, and this is why ill be checking periodically on them by taking them out to inspect. I want to get all the oil thats traped in the rubbers pores out. Might take a couple more times of removing and drying before that happens.
You didn't mention the engine.
I'm assuming that you are talking about a coil-on-plug configuration with a spark plug that sits in a well. There is a "connector" on the bottom of the coil that's essentially a spark plug boot.
The geometry of 3+ valves per cylinder pretty much constrains the plugs to sit in a deep well. Typically the valve cover has individual spark plug seals. Any leak causes oil to gather in the well, with no place to drain.
The oil doesn't cause any direct problem. It is electrically non-conductive, and a good thermal conductor. But over time the additives soften the rubber, making the connector prone to splitting.
Once split, the connector is very likely to cause a misfire that's similar to a bad plug wire. Not right away, but a week or two later after a carbon track builds up from minor discharges that don't initially cause a misfire.
If you replace the valve cover gasket and clean the connectors off before they start splitting, they usually will be serviceable. It's normal for them to ooze oil for a while, most from the conductive core and a trivial amount that has soaked into the rubber. If they haven't split, just clean them off.
The coils can split from the oil? Oh great, and this is why ill be checking periodically on them by taking them out to inspect. I want to get all the oil thats traped in the rubbers pores out. Might take a couple more times of removing and drying before that happens.
