I have a bad leak out of the crank seal on the timing cover on my 2004 6.2 Merc. While I have the motor out to swap the pan gasket and timing cover what else should I address?

Motor has 320hours on it and runs like a top except for the leak. In the last 2 years I've replaced both fuel pumps, plugs, and wires already. (Long story...... )

I think I'm going to put aluminum manifold and risers on since the motor it already going to be out. (Basic IMCO Thumpers), and might put on a set of tabs.

Is it bad to start replacing things like the rear main seal while I'm in there? The whole "if it ain't broke don't fix it".

Ideas?

I was going to start a similar thread...

We have 480 hours on ours and they still run great (knock on wood)...

I tend to also go with the if it ain't broke don't fix it motto...since you have it out I would do a compression test and leak down. Make sure the seals and bottom end are in decent shape. Anything in the top end can be done later when the motor is back in. The plugs, cap, lines, and risers (if they haven't been done) should get done. Again it comes back to what do you want to do as preventative vs what really needs to be replaced. Things like valves and lifters could get done but not sure they would necessarily need it.

Personally we will be doing plugs and caps this year as our risers were done 2-3 yrs ago. Other than what I have mentioned, can't think of anything else.

If you have the quick coupler block drains change them. They are a pain in the ass to do with the manifolds on... ask me how I know. One of mine started leaking so I did them all. I also upgraded to IMCO thumper no MPH gains but the boat planes and rides much better due to less weight.

Are you talking about the Merc drain system where there are only like 4 blue plastic wing nuts in the entire system? (2 for the sea pump, 1 for the circ pump, and 1 for the low point drain for the rest of the block and manifolds?) If so, which ones did you replace? The 2 block ones or the manifolds as well? I have the non air pump version of this.

I found a schematic of my setup. Are you talking about where hose(s) #19 plugs into the manifold, and where hose(s) #18 plugs into the block? Looks like part #3 for the block fitting, but unfortunately it doesn't look like they have part #'s for manifold fittings themselves.

http://www.boats.net/parts/search/Me...%29/parts.html

Good call on the compression and leak down. I'll play the rest by ear I guess. I have one day in my buddies shop to get it all done and was hoping to have all the parts on hand but I'm sure he could be persuaded with beer.

http://www.mercruiserparts.com/Show_...Point+Drain%29

I hate these breakdowns, but I think its 8 and 18. I still have the bags in my tool box. Will get the Mercury part number.

Correct me if I am wrong, but does the 6.2 have an oil cooler?

Throw a new bilge pump in while the engine is out. It's a whole lot easier now, and cheap while you are at it.

As far as I know, the 6.2's don't have a engine oil cooler. Unfortunate, since they also only have a 4.5 quart oil pan.

My 06 does not,the cooler in the rear of the engine is power steering.