Mercruiser 3.7 Cam Leak

ImperialV184

Petty Officer 3rd Class
Joined
Aug 4, 2011
Messages
99
Hello, i know there are a lot of posts on this issue. I have a Mercruiser 3.7 that was completely rebuilt. The Cam had the typical wear spots from the front seal failing, the rear seal seamed to hold but did have a small groove at the end of the seal. I had a machine shop add the speedi leaves to both grooved areas and reassemble. I have had it running for 2 years and just today noticed a small amount of coolant dripping from the weep hole. It was not a major leak but coolant was present. i was crushed to find this and shocked. Few questions, what is the typical time period for the front seal to fill once the repair with the leave is made? second question, one a leak is spotted how long do i have until i need to do the full repair again. Will the second seal hold as long as the weep hole is allowing the coolant to leak or is this something i have to deal with ASAP. Thank you
 

Grub54891

Admiral
Joined
Jun 17, 2012
Messages
6,069
The speedi sleeve should not have wore out that quick. Was the water pump replaced when you did the rebuild? Sounds like a bad pump seal. On that note, it could run for a year that way, or may fail tomorrow. Your choice, I'd replace it before you are in the middle of the lake and overheat.....
 

ImperialV184

Petty Officer 3rd Class
Joined
Aug 4, 2011
Messages
99
i Wish it was possible to change the water pump, it is build into the block and runs off the cam shaft. I was doing some reading and saw that once the first seal fails the weep hole helps prevent the second seal From failing. I am thinking the sleeve might not be put on in the right spot or was damaged on install. Anybody have any luck doing this repaired while engine is still in the boat?
 

stonyloam

Vice Admiral
Joined
Mar 13, 2009
Messages
5,827
No need to replace the pump, just replace the seals. It should have lasted longer than two years. Yes you can replace the seals with the engine in the boat IF you have room to pull the rotor off of the crank. A harmonic balancer puller from Autozone will get it off. You will need some additional spacers to get it back on. Do a search here and there are a bunch of folks that have done it.
 

kenny nunez

Captain
Joined
Jun 20, 2017
Messages
3,285
Inspect the sleeve for being damaged, the only other thing that could be causing the problem would be the bore that supports the front of the cam letting it move around too much.
 

wrestling coach

Petty Officer 1st Class
Joined
Jun 27, 2011
Messages
210
Be sure your speedi sleeves are on the cam snout where the seals will run as centered as possible.
 
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