3.0L Mercruiser crancase vent and exhaust elbow gasket

[mvoellinger]

Two questions. Both about a 2002 Mercruiser 3.0L with 90 hours on it.

1 - I have oil weeping out of the crankcase vent. It didn't appear to be coming from the vent itself, but around the grommet in the cylinder head cover and vent. Im going tomorrow to pick up a new one, but Im a bit concerned - do these things fail that enough oil would be coating the back part of the cylinder head cover, or am I facing a situation that could cause excessive blow by causing it? The grommet felt kind of hard compared to what Id imagine a new rubber one would feel like, and I know replacing it will tell me if I have a bigger problem, but I wont be able to run it for a week and its eating me up wondering!

2. I noticed some light rusty water stains on the exhaust/intake manifold below the exhaust eblow. I pulled the elbow off and it looks to be in great shape, jut a little bit of surface rust but no blockages or anything to indicate wear, Im thinking it was just the gasket starting to fail. I have a new gasket, but how do I get the old one off? Its very hard and very stuck on, using a razor blade could take me a full day. Any tips? or just keep hacking at it?

Im also replacing the thermostat, Im assuming use perfect seal on that, but the exhaust elbow is dry.

Thanks!

 

[JustJason]

Re: 3.0L Mercruiser crancase vent and exhaust elbow gasket

1. anythings possible. It's florida and gets awefully hot down there. It could be nothing more than a rotting/shrinking/deteriorated grommet, or you may have some blowby. If the hose itself on the inside is clean, then it's probably just the grommet.

2. it could be just the gasket, or it could be spray getting in the engine compartment. Tough to say without looking at it. What you probably should have done is give the boat a hard run, then while the motor is still running pull off the engine hatch and take a look. Standing water evaporates fast on warm manifolds but after a hard run you should be able to tell.

as far as getting the old gasket off...you can try a razor blade but be carefull not to nick the manifolds. It will help if you soak the gasket with penetrant or degreaser overnight. Anything will really help.
If you dont want to spend to much money get off what you can with a razor and then get a wire cup brush for the end of a drill or die grinder. Try and get a copper wire if you can. If you get steel wire then you take a chance of tearing material off of the manifold.
If you don't mind spending a few bucks, I started using 3M roloc bristle brushes a few years ago, and I love them.

http://www.shop3m.com/61500129806.html?WT.mc_ev=clickthrough&WT.mc_id=shop3m-AtoZ-Roloc-Bristle-Disc

You can buy singles at NAPA stores for like 6 or 7 bucks a disc. The arbor that holds it is like 10 or 15 bucks. But once you use them you'll never go back to a wire brush.

 

[chiefalen]

Re: 3.0L Mercruiser crancase vent and exhaust elbow gasket

Those disks are diamond encrusted?

For that price they should be ha.

I use a single edge razor in a holder, keep scraping.

The person who originally installed the riser did not make sure the mating surfaces where true and clean before he installed the riser.

The gasket should go on dry. Maybe when installed someone put some black crap on the gasket.

Good luck and don't over torque the nuts.

I can't find the torque for the riser nuts?

 

[mvoellinger]

Re: 3.0L Mercruiser crancase vent and exhaust elbow gasket

Those disks are diamond encrusted?

For that price they should be ha.

I use a single edge razor in a holder, keep scraping.

The person who originally installed the riser did not make sure the mating surfaces where true and clean before he installed the riser.

The gasket should go on dry. Maybe when installed someone put some black crap on the gasket.

Good luck and don't over torque the nuts.

I can't find the torque for the riser nuts?

Gaskets were original. The bolts still had the mercruiser enamel holding them in place.

Ive got the torque specs for them. I also bought a razor blade holder scraper, and a large chisel type scraper with a good sharp edge.