There are 2 other seals under the timimg cover which fail as frequently as the cam seal. Unless you removed the cover it is not possible to know which is leaking. These seals should normally get replaced all at once as a preventive measure while doing a timing belt change.

Don message was not referring to the rear main seal, he is referring to the plug at the rear of the valve cover which often leaks or worse still blows out under crankcase pressure.

As Don says a leak on the air intake bellows tube would not affect crankcase pressure. Is that the plastic pipe you refer to? Make absolutely sure the small brass nipple for the flame trap vacume line is clear. You can "feel" for crankcase vacume by applying your palm over the oil filler opening, in a few seconds a very slight vacume will build, you will feel it release when palm is removed. Do this before engine gets hot.

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David Hunter

I don't think that holes in the intake hose will affect crankcase ventilation. The system works in two regimes: At idle, and at speed.

At idle, vacuum gets to the flame trap directly from the intake manifold via the small nipple and small vacuum hose, which attaches to the top of the flame trap. That 1/4" diameter hose (and nipple) often become plugged, which means no vacuum at idle BUT plenty of crankcase pressure at idle. You can ream out the nipple, and you should simply replace the hose.

The intake hoses have no effect on the vacuum inside the intake manifold while at idle (or any other time).

At speed, the crankcase runs at slightly positive pressure, but this causes the vapors the exit through the flame trap and into the intake hose -- which means that they're inducted into the engine and burned.

Again, small holes in the intake hose won't affect crankcase pressure.

The oil cap used on an '87 is the newer, lighter plastic design. They tend to rattle even when you have sufficient vacuum. It's best to measure crankcase pressure with a gauge.

Your cam seal may have failed because it was defective or because it was improperly (or poorly) istalled or because the crankcase pressure went higher than you realized.

I'd also reach behind the head and feel the big plug. Confirm that it's firmly in place.
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Don Foster (near Cape Cod, MA)