It’s simply amazing how many times the rear crankshaft seal gets blamed for an oil leak when there are so many other places at the back of the block that can either be the root cause or at least a contributor. The rear oil seal retainer on the Y-Block is just one of these items that more often than not gets overlooked when it comes time to address an oil leak at the rear of the engine.
Upon tearing down a 292 Y engine for a rebuild, it was noted that the back of the block and oil pan were extremely oily but not much more was thought about it at the time as oil leaks on these engines seem to be common place by the time a rebuild is needed. Upon pulling the rear seal retainer loose from the block, it became apparent that the retainer itself was the source of an oil leak and had been abused somewhere in its distant past. In this particular instance, both of the grooves in the rear oil seal retainer where the side seals slip in place were distorted enough that the side seals themselves were not adequately up to the job for which they were designed.
Two different thoughts come to mind on how these grooves became warped. The first one is that the grooves had become distorted when someone had tried to drive the replacement side seals in place with a considerable amount of force. The older style of asbestos seal was being used in this case and are potentially hard enough to actually exert this kind of force on the soft metal of the seal retainer. The other thought (and much more likely) is that the rear seal retainer had been pried out of the block sideways instead of being simply being lifted straight up and/or raised as would be normally recommended.
For this particular rebuild, I simply replaced the rear seal retainer with a visibly ‘good’ one and went on. But if I had been in a bind and needed this particular retainer, then it could have very likely been straightened with some gentle persuasion using a hammer and reused. Point here is that without being straightened, the retainer would have undoubtedly just leaked again and would have to be addressed again in the near future.
When working on these engines there just seems to be no end in the number of things that can go awry and just when you think you’ve got it all figured out, something else comes along. The warped side grooves in the rear seal retainer just gets added to the growing list of things to watch out for.
Until next time, Ted Eaton.
Originally published in the Y-Block Magazine, Nov-Dec 2008 Issue #89, Vol 15, No. 5