Mercruiser 4.3 Oil Leak - Front Crank Seal?

[wisyooper]

I've read a couple of several years old posts regarding the oil leak on the lower front of 4.3 liter Mercruiser engines. I have a 2007 Maxum with the 4.3 liter with 140 hours and have an oil leak near the front crank case cover. I suspect it is either the crank case cover seal or the crank seal itself.

I understand that the crank case cover replacement requires removing the oil pan - a job that requires removal of the engine. I am thinking of replacing just the seal on the front crank shaft and have the Mercruiser shop manual. A couple of speciality tools are required.

My question - is this a fairly straightforward job and do I need the specialty tools? For background, I am mechanically inclined (have replaced the head gasket on my 4-cylinder car myself, replaced struts, dropped transmission pans, new timing belts, etc.).

My other question - is anyone familiar with this issue and is it most likely resolved with the crank seal, rather than the crank (chaincase) cover?

As an aside, I am running about 78 psi at 2000+ rpms.....seems a little high to me but I am relying on the boat's pressure guage rather than a reading on a mechanical device.

Thanks!!!

 

[Bondo]

Re: Mercruiser 4.3 Oil Leak - Front Crank Seal?

I've read a couple of several years old posts regarding the oil leak on the lower front of 4.3 liter Mercruiser engines. I have a 2007 Maxum with the 4.3 liter with 140 hours and have an oil leak near the front crank case cover. I suspect it is either the crank case cover seal or the crank seal itself.

I understand that the crank case cover replacement requires removing the oil pan - a job that requires removal of the engine. I am thinking of replacing just the seal on the front crank shaft and have the Mercruiser shop manual. A couple of speciality tools are required.

My question - is this a fairly straightforward job and do I need the specialty tools? For background, I am mechanically inclined (have replaced the head gasket on my 4-cylinder car myself, replaced struts, dropped transmission pans, new timing belts, etc.).

My other question - is anyone familiar with this issue and is it most likely resolved with the crank seal, rather than the crank (chaincase) cover?

As an aside, I am running about 78 psi at 2000+ rpms.....seems a little high to me but I am relying on the boat's pressure guage rather than a reading on a mechanical device.

Thanks!!!

Ayuh,... Welcome Aboard,... achris is the poster intimate with that issue,... Hopefully, he'll see this,...

Question, #1,... Well, if ya wanta play a Mechanic, ya gotta have the toys,...

nope, this job can't be done with vise-grips, a screwdriver, 'n paperclips,....
you'll need pullers, 'n drivers atleast,...

Chevy timin' covers have always been Under the oil pan,...
I know folks who've changed 'em, without removin' the oil pan,... I won't,...
I find it easier to just pull the motor,...

Changin' Just the seal, can be done,... But I'd be usin' Specialty Tools to do that too...
Success depends on the Why it's leakin', which ya won't know til it's apart,...

 

[achris]

Re: Mercruiser 4.3 Oil Leak - Front Crank Seal?

Welcome to the club....

Yes, you have a distorted oil pan (fault in the casting). And about 140 hours is when they all go... Only one fix for the problem you have... Replace the oil pan and the timing cover... which means.... Engine out!

The timing cover is composite and can not be changed without removing the oil pan, which can not be remove with the engine in the boat.

Now, don't buy your new oil pan and timing cover from Merc... Way too expensive. (Merc USA want $257 for the timing cover and $455 for the pan. And almost double that in Australia... ) Go to http://www.buygmpartsworldwide.com/ and look for a truck (of the same year as your engine, and I wouldn't mind betting it's a 2006, not a 2007. The boat's 2007, not the engine) with a 4.3 engine. I use a 2006 GM Silverado 1500, V6 engine. The oil pan costs about $163 and the timing cover about $40. You don't need to buy a oil pan gasket because it comes with the oil pan.

You can pull the balancer off the front, like I did the first time (and the second, and the third), but to replace the seal (which isn't the problem) you NEED the special tools...

Chris...........
Have a read of these threads....
http://forums.iboats.com/mercruiser...-v6-cracking-timing-covers-update-373060.html
http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/oil-free-bilge-finally-548054.html (and over a year on and it's still oil-free )

Here's a good place to get a new cover -> http://www.gmpartsdirect.com/results.cfm?singlepart=1&partnumber=93445880

 

[wisyooper]

Re: Mercruiser 4.3 Oil Leak - Front Crank Seal?

Welcome to the club....


Now, don't buy your new oil pan and timing cover from Merc... Way too expensive. (Merc USA want $257 for the timing cover and $455 for the pan. And almost double that in Australia... ) Go to Buy GM Parts Worldwide * Genuine Replacement * GM Parts Accessories and look for a truck (of the same year as your engine, and I wouldn't mind betting it's a 2006, not a 2007. The boat's 2007, not the engine) with a 4.3 engine. I use a 2006 GM Silverado 1500, V6 engine. The oil pan costs about $163 and the timing cover about $40. You don't need to buy a oil pan gasket because it comes with the oil pan.

You can pull the balancer off the front, like I did the first time (and the second, and the third), but to replace the seal (which isn't the problem) you NEED the special tools...

Chris...........
Have a read of these threads....
http://forums.iboats.com/mercruiser...-v6-cracking-timing-covers-update-373060.html
http://forums.iboats.com/mercruiser-i-o-inboard-engines-outdrives/oil-free-bilge-finally-548054.html (and over a year on and it's still oil-free )

Here's a good place to get a new cover -> GM Parts Direct: 93445880 - COVER

Thank you so much for all the help!! I appreciate it!

As an update, I haven't done anything yet other than to pull the crank position sensor which did have a lot of oil on it. I replaced the o-ring and hoping this solves my problem for the short term. I ran a piece of paper towel in and around the crankshaft behind the harmonic balancer - no oil at all. So the leak is either the cover or the CPS. I understand I will likely need to pull the engine and replace the oil pan and the timing cover.