96 2.0l Sohc Pushing Out Oil Seals

[FISHAIRE]

The history:
110k oil in antifreeze -MLS head gasket and timing belt
150k pushed out rear main seal- replaced
170k pushed out front main seal-replaced
checked pcv valve - clear and working, pcv tubes not cloged
measured air preasure in valve cover always sligtly negative at all engine speeds.
233k (yesterday) pushed out front camshaft seal
checked pcv valve - clear and working, pcv tubes not cloged
also does bubble air into antifreeze resivour during hot months
oil consumtion 1/2 quart between changes (negligable i think)

I assume these seals are being pushed out by internal crank case pressure
however based on my my testing @ 170k there is no continuous pressure in the crank case.Thefore the pressure must be somthing that happens intermittently. Also if there were a constant pressure in the crancase I should see some oil seepage from the fornt and rear main seals.

Has anyone ever heard of these seals being pushed out? And if so is there a correctable cause?

Thanks for your help!

P.S. Should I replace the head gasket again to correct the bubbles in the coolant?

[denisond3]

Our 97 had a leaking rear main seal at 140,000 miles, when it was almost ten years old. About 70 miles per quart of oil. I pulled the engine and replaced the rear main seal, front main seal, and camshaft seal - along with the alternator, heater hoses, timing belt, tensioner pulley, water pump & cam position sensor/connector. All of the seals were MUCH too easy to remove. They have a rubber outer coating over the metal shell, instead of the older style which is just the metal shell; and I think that design will loosen up in time as the rubber goes senile. After I removed the 'flywheel' I pulled the main seal off with just my fingernails! So I plan to take the engine out again after 8 more years (2015), and replace those seals again.
You should replace the timing belt, tensioner pulley, & water pump again - if it has been 100k miles since it was done. I only mention the water pump because you have to remove the timing belt anyway to replace the water pump. And the tensioner pulley should be replaced each time the timing belt is replaced, because it might not last another 100,000, and isnt too expensive.
The normal coolant temperature in the engine head is well above the boiling point of water when the engine is running. So the bubbles in your coolant recovery reservoir might just be the hot coolant being pushed out of the head & boiling a little at atmospheric pressure. You only need to worry if it is either losing coolant (the level in the coolant rec. res. is lower when you look at it each morning with a cold engine) or if when you remove the radiator cap (on a cold engine) the coolant is not right up at the bottom of the cap.
If you read old posting in this subforum, you would find that seals coming out is all too common on Neons - when they have a many years/miles on them.

[FISHAIRE]

Thanks for the reply,

I finished putting it back together last night.
New cam shaft seal, timing belt and water pump.

I did this with the engine still in the car and thought it might be a problem to get the new camshft seal in with only about 4 " to the inner fender. All I did was tap it in with a 34mm deep socket! No hammer (no room) No crowbar to push agist the fender. It just popped right in.

Obviosly these seals will fall out again eventually. As the engine ages more compression gasses will slip by the rings and start to pressurise the crancase beyound what the pcv valve can relieve. Then POP! Rather like an automatic self destruct.

Has anyone out there ever heard of an improved (not rubber coated) crank and camshaft seal desinged for these engines?

Thanks,
Dan