Originally Posted by Genesis
The worst one I had on mine (and that I've seen on others) are the covers on the cylinder heads
Does "covers on cylinder heads" = valve covers?
No... below... The valve covers are a separate issue. If you have the cast covers (most do) then if the seal on those is leaking due to being old it's easily replaced - it just pulls right out of the casting and you put in a new one. No big deal at all. Note that the elastomer on the valve cover bolt (the big red rubber thing) is what provides the tension on that seal, so if your valve covers are leaking check those as well - the seal on the cover itself may be fine but not under sufficient tension.
where the throttle modulator pipe goes through (rear outboard side covers.) Those have a habit of leaking and are a pain to get to stop it. I never did manage to get that to quit COMPLETELY.
Look under the valve cover on the cylinder head, aft. There are small rectangular covers with a bolt on each end longitudinally. One will have a pipe going through it (it's the air pipe for the throttle modulator, and goes to the air horn); the other will be a blank plate. Oil pools in the inside of the cylinder head against them and for some unknown reason they seep oil on every 6v92 I've ever seen. Not a lot, but they do - just enough to be a PITA.
The other place that I've seen leak a lot is the rubber boot between the block and the blower encasing the blow driveshaft - easily replaced if you're willing to pull the blower.
How much of a cramp is it to pull the blower? Any post-install adjustments or settings required? Anything that goes "boing" and flys across the engine room when the blower is pulled?
A fair bit. You have to disconnect the racks as the governor is mounted on the blower, plus the fuel lines since the fuel pump is mounted there too. It also has a shatload of oil that pools in it that doesn't drain out when you shut down, which means it will make a hell of a mess. There's an inside snap-ring that retains the driveshaft for the blower you have to remove from the rear to extract the blower driveshaft - and you CANNOT drop that inside the gear train or you're in BIG trouble. Stuff a shop rag in there good so if you DO drop it it doesn't go down inside the engine! You know Murphy, right?
Reassembly requires a full tuneup and you should have a blower drive alignment tool. You can get the alignment ok without it, but it's not advised. Reassembly itself is pretty easy; the tune-up is a tune-up. The procedure is in the shop manual and is pretty straight-forward, but is very frustrating when it comes to setting the racks if you haven't done it a bunch of times - it's a "feel" thing to get right.
If the blower isn't leaking (you can see the oil under the boot and in the back of the blower if it is) then don't screw with it. If it IS leaking, consider the below if the leak is coming from the boot (and it probably is)....
The "cut the new boot to install" method (to avoid pulling the blower) is one I don't like, but some people use it.
They do this to avoid the pull and replace operation. :-> Considering that the worst case is that it still leaks if you do it and it doesn't work, and replacing the boot that way takes almost no time and disturbs nothing, whereas the other way requires dismounting the blower, well, you choose.
If you have flange-mounted alternators those are also known to leak. The common expectation when you get a leak back there is that it's the seal that the drive coupling goes through. Not always! More than a few times I've seen the adapter plate leak oil where the bolts are that fasten it
The bolts that mount the alternator, or are you referring to bolts I cannot see that mount the adapter plate? Is the solution putting permatex on the bolt threads?
The bolts that mount the adapter plate. Once you remove the alternator you can see them. It may not look like it's leaking there, but it sometimes is. The solution is to either put permatex on the bolt threads for the adapter plate or seal the gasket around the bolt recesses. Either works. If you're getting oil slung around in the adapter housing it's 50/50 whether its the seal or the bolts. The usual answer if you call a mechanic is to sell you a hub kit. If the seal is bad then ok - but if the bolts are leaking you just wasted money on something that wasn't the problem.
(Be aware that the alternator positive lead is hot with the engine off. Use caution, pull the ANL fuse in the main panel, or pull the battery positive lead before you screw with it.)
There were also a couple of other places that leaked oil on my engines, particularly around the cover plates and accessory drive locations on the gear train, but those weren't too hard to clear up by dismounting the offending plate or device, getting rid of the old gasket and replacing it.
I never completely got rid of the oil leaks on my engines, but I got pretty close - to the point that there wasn't any dripping on the oil pads under the engines. But the little seeps here and there... nope. Always had a couple of those that I was wiping off now and again....
