I just observed a large oil leak dripping between engine and transmission at the bell. I assume it is a rear main. I replaced that before when I had the engine out a couple years ago. It is very steady and drips all the time and steady. Can the rear main in a B20 be replaced without pulling the engine? I have pulled the gearbox before. It is not gearbox fluid. I have the green books but none of them have this procedure in them.

B20 A/B engine green book #2 page 24 gives details of fitting the seal. Shows a Volvo special tool for centring which is important regardless of whether you use the felt or neoprene lip seal. Felt seal described in this section. Nothing wrong with fitting a new felt seal. It will accommodate a small amount of misalignment compared to the lip seal and will seal better if the crankshaft surface has been scored by grit. A poor surface can destroy a lip seal after not many miles and you are back to square one. Felt seals last a long time if they are used where the oil is clean and the engine is used enough to allow them to stay wet. Engines that have been unused for years will often leak because they are dried out but can, if you are lucky, revive themselves after new oil gets around the rear main bearing. New felt seals are cheap. Soak in engine oil overnight and then squeeze out excess before fitting. I've no statistics but fro comments from forums and by personal friends fitting new lips seals is less likely to cure the leaks than a new felt one. With the lip seal this may be down to poor centring and damage to the seal when fitting. As said, the felt seal is reasonably foolproof and easy to fit.

Since I have the new rubber seal setup I do not think I can go back to felt seals. I drive this car often so I do not think it is drying up. It has alway leaked a little, even after I replaced the seal the first time. It is just now the gates have opened and there is a huge leak, 10 inch diameter stain where it sits.

Yes, you can change the rear main seal with the transmission, clutch and flywheel removed.

Do you remember which seal you installed, the original felt or the updated rubber seal?
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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com

It sounds like what happened to my B20. After sitting unused for some time I put the 144S back on the road and drove up to the Lime Rock Park race track where I planned to run on track for the day. Getting to the paddock I positioned the car to back into a space. Once parked I could see an oil puddle where the car had been and a steady drip where it now sat. I opted not to run that day and took photos instead. The 145 mile trip home was nerve wracking as I stopped every 15 miles or so to check on things. Much to my relief there was no more loss of oil. I even drove the 650 miles to my son's shop in NC with no drip. Upon removal I found the felt seal shriveled and split. When the split rotated facing down I'm sure that's when the drip would occur. At that point I switched to a later seal housing with neoprene seal. If you also still have the felt seal you can use a more easily found seal housing from a B21, 23, 230. Just remember the two bolts from the oil pan up into the seal housing will need metric threads (8mm) -- Dave

I have the updated rubber seal. Is there a procedure somewhere to see this done. I replaced it with the engine out before. I did not think it would leak after a few thousand miles.

I can think of at least two possibilities of error with the rubber seal. The lip can get folded back on installation - but I would think that would/could result in an immediate leak. Or--the spring inside the seal can pop out of place on installation which might take a while before oil can seep past. I pack the back of the seal with heavy wheel bearing grease to contain the spring. -- Dave

I can think of a couple of more possibilities for oil leaks at the rear of the engine.

The surface on the rear crankshaft for the rear seal might be damaged and if that is the case, there is a repair sleeve to fix that problem.

The oil pan gasket or the gasket for the rear main seal housing can leak and though it almost never happens, the core plug for the camshaft can leak.

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Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502
hiperformanceautoservice.com or oldvolvosonly.com