hello folks. my trusty brick wagon sprung a leak. drove from va to atl ga. no problem. on the way back, noticed rear window covered with oil. determined that it was coming from the front cam shaft seal. i checked my flame trap, and it was clear.

this happened about a year ago, and i found holes in the plastic air intake just below the throttle position sensor. when i fixed that the seal leak "healed" itself.

on the road i didn't find any new holes, didn't find any thing out of the ordinary.

course i was on the free way and my main intrest was getting home. so 5 quarts of oil latter i'm home.

got any idea's, test, tips. does this seal have a rep. for spontaneously failure.

how? why? how do i keep it from happening again.

thanks

If it's the front seal, near the water pump, then it may have failed from high miles PLUS excessive crankcase pressure. Replacing the three front seals (cam, i-shaft, crank) are good to do when you also have the front apart for a timing belt.

BUT you should also confirm that you really have repaired the flame trap and associated plumbing.

Keep in mind that if the cam seal leaked, it probably poured oil over the top water pump seal, sometimes called the "mushroom" seal. This seal is rubber, so the oil will cause it to swell and soften. Don't be surprised if it begins to leak antifreeze.

If you lost the seal at the rear of the head, the big plug, then you must install a new plug. (This is also caused by excess pressure from a plugged crankcase ventilation system.)

You can install the IPD retainer or you can build your own from a scrap piece of aluminum flat stock. Dimension are shown below.

this is not a rear seal problem. thanks for the info though. its the front seal, it has about 30k on it. i replaced it when i did the timing belt . it is definitely the front seal on the cam shaft. i read the faq on the flame trap and plumbing. all that work was done about six months ago. i even cleaned the oil separator box thing at the block. cleaned the pipes and tubes. thats when i found the air intake pipe had holes in it, which i fixed. is there some thing in the intake system that would effect the amout of vacuum being pulled on the crank case. my oil filler cap rattles by the way.

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.

--
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.
--
Don Foster (near Cape Cod, MA)

This happened to me once. IPD sells the following to prevent this from happening. Check out the link below.

http://www.ipdusa.com/ProductsCat.aspx?CategoryID=95&NodeID=4991&RootID=629

thanks for the link, i'll hang on to it for future ref, but this is a front seal leak, not a rear seal leak.