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Front crank seal saga on 1984 300D.
Thanks for this wiki. I had seen it but forgot when doing my oil pump tensioner, which became cam chain rail swap & timing project. I didn't anticipate problems since I previously changed the front crank seal on a used engine (1982?) before installing it in my 1985 300D. On that one, I "just did it" without much thought and must have gotten lucky (no leaks in 3 yrs). I did tip that engine over on the stand in trying to loosen the crank bolt (scare, no damage).
After seal installation and rotating the engine (cam timing), I noticed the seal sitting crooked. I pulled off the damper to check and found the seal lip was torn and the spring popped off (photo). Apparently, the lip got pinched between the seal ring and damper hub. I probably assumed the lip runs on the damper's hub so didn't check that it was over the seal ring. The main lip runs on the seal ring and the outer dust-lip appears to run on the damper or in the gap between the two. Perhaps on the prior engine, I had pushed the inner lip up around the seal ring. Things are more obvious on an engine stand.
I'll contribute 2 thoughts.
1. Instead of making the plastic lip expander here (good idea, comes on newer engine rear seals), one can use the seal ring as an expander. If you can pull it forward (mine was easy by hand), work the lip over it (rolling motion, blunt screw-driver helps), then slide the seal ring in as you tap the seal in. If you can remove the seal ring completely (I had to slightly file the edges of the crank key slots), you might push in the ring after the seal is installed, which would expand the lip. A new ring is $10, but I flipped mine over (polished new surface of gunk) since it had a slight groove where the seal ran. If you remove the oil pump (possible w/ upper oil pan on, I did), you have better access to the seal ring, or there is a special bolt puller tool (expensive).
2. I wondered what stops oil from leaking between seal ring and crank. It appears nothing. From there, it could either pass thru the dust-lip on the damper or thru the metal-metal gaps at the shaft and washers. No concerns on a new engine, since it should have negative crankcase pressure (from PCV), but as they wear and get blow-by, the crankcase gets pressurized, so all possible leak paths become reality. I coated the ID of the seal ring w/ gasket sealant to block that inner path (resists oil and stays pliant). It may not be sufficient, but shouldn't hurt.
I had other issues w/ the round keys that lock the damper to the crank, but I'll put in a separate post. I have read where others had problems, and even caused permanent damage to the crankshaft.
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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans
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