Oil leak? PCM 454

[cadunkle]

My 454 is leaking oil into the bilge. Not a huge amount, but over the past 40 hours it was down maybe 3/4 of a quart. Bilge is oily and nasty but nowhere is obviously leaking. no leaks and clean bilge at beginning of the season. Front and rear of intake is not oily and seems sealed well with RTV. Valve covers are not leaking either. It's definitely not burning it as it runs great and exhaust is clean. Are there any particular areas I should check to figure this out? I hate having an oily mess in the bilge and when the pump comes on you can tell it's oily water.

Hoping I don't have to pull the engine to get this sorted but if I can't find anything I'd be tempted to just pull it over the winter, check everything while I'm in there, and put all new gaskets on it. Any typical areas these PCM 454 leak that I should check? I've always been a Ford guy and built plenty of small blocks and 460s, but never done a BBC before.

[beast 496]

The old Mark iv 454's had two piece seals on the crank. This is a particular area of seapage, as well as the rear corners of the oil pan. I had a Saltare earlier this summer, with a 454 and the oil drain hose seeped oil at the crimp fitting at the pan connection. Not really an easy fix, as we had to pull the engine to remove the plug/hose assy. Cost was minimal though. Good luck Al

[wotan2525]

I've fought this exact issue on several occasions. One time the oil plug remote drain fitting hit the hull and cracked the pan. Another time the fitting itself was leaking -- I ended up welding the pan, then welding a nut on the inside of the side so I could move the remote oil drain to the side. The pan just sits too close to the bottom of the boat.

Once I resolved those issues, it was still leaking.... from somewhere. I replaced the timing cover gaskets and pulled the engine to inspect the rear seal. Seal seemed good. Replaced valve covers (which were cheapie stamped Summit brand) with some heavy duty cast aluminum ones and new Fel-Pro gaskets. I believe that I elimaniated about 90% of the leaks.... but it still leaks from somewhere. I've just learned to deal with it. I put a cup full of laundry detergent in there when I pull it out every time. Seems to help keep it reasonably clean.

This year I started noticing transmission fluid in the bilge. I've replaced the coolant lines and checked every where else that it could be leaking from. Another mystery. Has leaked about a quart and a half this entire summer (about 120hours.)

[cadunkle]

I should note the engine was rebuilt by previous owner in 2007 and looks pretty clean on the outside, no big oily mess running down the front or sides, no puddling of oil anywhere. Is there enough room below the pan to remove the oil drain hose and replace with a regular plug? I don't use the hose since it doesn't drain well or completely so that would be an easy thing to eliminate as a possible source.

[haugy]

Rear main seal would be my guess. Notorious for leaks.

[wotan2525]

I should note the engine was rebuilt by previous owner in 2007 and looks pretty clean on the outside, no big oily mess running down the front or sides, no puddling of oil anywhere. Is there enough room below the pan to remove the oil drain hose and replace with a regular plug? I don't use the hose since it doesn't drain well or completely so that would be an easy thing to eliminate as a possible source.

I doubt it. Mine doesn't even have enough room to get your hand under there.

[ruby23m]

I had a pretty big leak too this year, it turned out to be the drain plug was a bit loose on the oil pan. It took me about 20 minutes to be able to get the wrench on it to turn it half a turn closed.

[sybrmike]

Good luck if it's the remote oil drain plug - definitely not much room down there. You might try blindly cleaning the area and then placing a clean paper towel underneath the plug area & let it sit a few days and check for spotting. If that's the source, you might get enough room to work by unbolting the coupling and using the rear mounts to jack up the rear of the engine. I had to do this. During the rebuild, I installed a longer drain hose and replaced the original plastic crimp ring with a screw hose clamp while the engine was out. After installing the engine, I discovered that the head of the screw clamp was binding on the hull & preventing the rear to drop the last little bit I needed for coupling alignment. By jacking up the rear of the engine with the mounts, I was able to get just enough room to remove the screw hose clamp and used needle nose pliers to slide on a spring hose clamp. It's just that tight down there...

[wotan2525]

By jacking up the rear of the engine with the mounts, I was able to get just enough room to remove the screw hose clamp and used needle nose pliers to slide on a spring hose clamp. It's just that tight down there...

Eeek! I was so paranoid about this leaking a third time that I went over to pirtek and had a custom hydraulic fitting made. Now it's all one piece and couldn't possibly leak unless the hose failed.

[Salty87]

i've had to change the timing cover gasket too. if you run your finger along the lip under the harmonic balancer you should find oil if it's from there.

i bought an oil drain hose but never connected it, no room.