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Hogwild
07-14-2012, 10:14 PM
So I've noticed that after the last few times I've taken the boat out, a little oil drains out with the lake water when I pull the plugs. Also I looked down in the bilge and have noticed small oil puddles. Is it normal for the engine to leak a little oil? And if not (which i think not) what are the common causes for it to leak and where should I check so that I can make the fix? Thanks guys. BTW, boat only has 320 hours.

dmayer84
07-14-2012, 10:23 PM
Is the oil filter tight?

mikeg205
07-14-2012, 11:20 PM
main seal in front of trans...?

Hogwild
07-14-2012, 11:25 PM
I checked the filter first and it's nice and tight.

Not sure about the tranny. Would it be leaking motor oil from around there though? I still use regular trans fluid in it.

Or what seal would you be referring to? I still don't know much about this boat yet and am not the most mechanically inclined.

mikeg205
07-14-2012, 11:28 PM
crankshaft seal is the one I am referring to.

Hogwild
07-14-2012, 11:36 PM
crankshaft seal is the one I am referring to.

Hmm. Not sure. I'll see if I can look better under there tomorrow. If it is the seal that you're talking about, do you know if that's a pretty easy fix? Or do you think I should wait until after the end of the year when all the fluids are drained?

mikeg205
07-14-2012, 11:39 PM
you have to pull the transmission off to get to seal...so not easy, time consuming as well.... if slow leak I would wait till end of season and put something under motor to catch oil... IMO

mikeg205
07-14-2012, 11:47 PM
this thread shows the where you need to get to...

http://www.mastercraft.com/teamtalk/showthread.php?t=35263&highlight=main+seal

Philscbx
07-15-2012, 12:10 AM
One option-

Iv'e had great luck with Justice Bros engine oil products.
Their engine stop leak is made to recondition oil seals.
If you can run it on the trailer- clean bilge with solvent rags in Naphtha.
Lay newspaper under engine to spot check actual leak source -
Make a reference fold in paper to reference tranny/engine block joint.
Spot check oil pan - valve covers - drain hose & fitting on oil pan.

Install sealer.
Warm up Engine to normal then shut off - let it sit..
Remove & check paper after engine cools down.

Couple runs on the lake - sealer should take effect.
http://justicebrothers.com/images/thumbs/Engine-Stop-Leak.jpg

Throw solvent rags in cardboard box - they will dry out overnight outdoors - can be reused.
Any home builder supply carries it in quarts & gallons - it's cheap and low oder - perfect for oil clean up.
Like that spot on the driveway. Spill solvent on it - use shoes to grind in kitty litter into it - spot gone.
Throw litter in same box - it too can be reused. Good Luck...

petermegan
07-15-2012, 12:40 AM
I will admit I am not totally familier with the stop leak products but generally don't like the idea. Just worry what they may be doing for lifters and other areas of the motor. Sounds like it may be a rear main seal, bugger.

Cloaked
07-15-2012, 08:31 AM
I will admit I am not totally familier with the stop leak products but generally don't like the idea. Just worry what they may be doing for lifters and other areas of the motor. Sounds like it may be a rear main seal, bugger.
+1 X 100 ................

mikeg205
07-15-2012, 11:19 AM
Noooo do not use those products... it will swell all your seals and you will have to use that stuff all the time. Somehow the seal must have gotten some dirt in it and wore the seal most likely. Car seal replacement is about $900 parts and labor...but you need a lift etc... I am not a mechanic, but if its just slowly leaking...more like seeping and not running out a bunch of oil just keep an I out on it.

In the off season you'll have a project...unless something is wearing the seal. watch the leak if it worsens quickly..get it done... if its a steady seepage/leak. Watch oil and have big project in the fall winters spring... you'll get to do and learn a bunch of stuff... or if you have the means...have it done. I am sure a bunch of folks here would provide the know how on which tools to use...especially if when you get to the actual removal of the leaking seal.

Philscbx
07-15-2012, 06:48 PM
Here's the link to the product - http://justicebrothers.com/pages/products/products_carcare_oil_additives.htm
Never been a claim of damage - As a Mechanic, it simply works.

There's an oil leak -
leaving an oil slick everytime it's pulled out, in water, etc is a bigger issue.
It's a not a radiator stop leak with particles - it's simply makes dry / shrunken seals go back to normal.

The next oil change removes it - Never has to be retreated.
These guys have been at this professionally for 70 years.

Can always tear it down in winter to make permanent repair.
Which you have to now to stop it - Summer gone- huge expense.
Simply Depends how much you want to deal with the constant mess.

This also causes crashes on the freeway - with invisible oil slick sprayed on the surface.
I ran into it one night following boat - and almost lost control.

Hogwild
07-15-2012, 10:13 PM
So after running it for a few hours today here is what is collecting in my bilge. I have gotten under there and checked the filter (no oil leak there) as well as the drain hose all the way to the pan (no leak there either). I didn't have time to put any cardboard back there and run it to see where the drip was but I left something to catch them overnight and will have to go back and see where its coming from. Now I know why they call boats moneypits 8p

I am concerned at the amount of oil that is back there as it seems to be getting worse.

http://i1191.photobucket.com/albums/z480/Kwilson007/011.jpg

http://i1191.photobucket.com/albums/z480/Kwilson007/010.jpg

mikeg205
07-15-2012, 10:18 PM
How much did you lose? Did you check the dipstick before and after...?

Hogwild
07-15-2012, 11:24 PM
How much did you lose? Did you check the dipstick before and after...?

Yeah, but didn't do a fair comparison. I checked stick before and it showed in the operating range but maybe 1/2 quart low. I added some to be on the safe side but didn't measure how much. (stupid i know). Afterwards I checked the stick again and it was at upper end of operating range. So I guess I may have to wait until I take it out again to get a good measure.

byronic
07-15-2012, 11:30 PM
You might check the oil pressure sender unit. I've had them leak around the joint in the case. Hard to spot because the drips can fall on a hose and run along way from the leak. A few drips can make a mess in a clean bilge.

Hogwild
07-15-2012, 11:47 PM
You might check the oil pressure sender unit. I've had them leak around the joint in the case. Hard to spot because the drips can fall on a hose and run along way from the leak. A few drips can make a mess in a clean bilge.

Any idea where it is located? Searching the forum now.


I had the dealer replace the temperature sending unit when I had another issue. Do you think they may have messed something up doing that?

Hogwild
07-16-2012, 09:38 PM
I left some cardboard underneath but nothing really dripped overnight. Then today I felt all around the entire engine and could not find any oil residue indicating a leak except in one spot. So I ran the engine for a little while and noticed the leak coming from one place. It drips about once every 2 secs at idle speed, but I didn't throttle it up to see if it drips more at higher rpm's. My finger shows where the leak is coming from and I took a few different angles. Could someone tell me if this is the rear main seal is located? If so, does anyone know about how much it would cost to repair and if you would do it now
or wait until the off season? I know another poster mentioned about $900 for a car seal, but didn't know if it was the same for a boat.

http://i1191.photobucket.com/albums/z480/Kwilson007/012.jpg

http://i1191.photobucket.com/albums/z480/Kwilson007/007-1.jpg

http://i1191.photobucket.com/albums/z480/Kwilson007/006-2.jpg

Table Rocker
07-17-2012, 09:54 AM
Where you are pointing is the front of the engine, where the oil pan meets the timing cover. I am not sure why you would see so much oil dripping from that location. A drip every 2 seconds seems like a lot for an oil pan gasket. There shouldn't be any pressure in that area, just a gravity flow of oil back to the pan.

I would make sure the crankcase is vented properly (pcv system working) before I started working my way to the leak. A timing cover gasket set might fix your problem, but it is hard to say by just looking at the pics.

Chasing oil leaks is not something anyone wants to be doing.

Hogwild
07-17-2012, 01:48 PM
Where you are pointing is the front of the engine, where the oil pan meets the timing cover. I am not sure why you would see so much oil dripping from that location. A drip every 2 seconds seems like a lot for an oil pan gasket. There shouldn't be any pressure in that area, just a gravity flow of oil back to the pan.

I would make sure the crankcase is vented properly (pcv system working) before I started working my way to the leak. A timing cover gasket set might fix your problem, but it is hard to say by just looking at the pics.

Chasing oil leaks is not something anyone wants to be doing.

Yeah I'm a little perplexed. It's almost as bad as trying to find a water leak coming from your attic.

I'm like you in that if that area is not under a lot of pressure it shouldn't be leaking that much.

Hogwild
07-17-2012, 01:50 PM
Here's the link to the product - http://justicebrothers.com/pages/products/products_carcare_oil_additives.htm



Phil, where did you find this stuff? I'm curious if I decide to go this route because I looked all over the web and even O-Reilly's, etc and couldn't find it anywhere..

Kyle
07-17-2012, 02:01 PM
I would never put oil leak stop products in any of my engines. I would fix it the right way.

Think about the bearings, rod, main, and cam, then think about the lifters.


I would clean all of the oil off of the engine with brake cleaner. Then trouble shoot the exact location of the leak.

If I were you and did NOT have time to fix it right away, then I would add oil and maintain full level of oil and just let it leak until you do have time to fix it right.

I would only add oil to the crankcase.

Hogwild
07-18-2012, 08:55 PM
Well if I can't find another source/cause for the leak it looks like I may end up pulling the motor this fall. Any suggestions of what else to do while I've got it out of the boat would be appreciated.

piper_chuck
07-18-2012, 10:25 PM
Well if I can't find another source/cause for the leak it looks like I may end up pulling the motor this fall. Any suggestions of what else to do while I've got it out of the boat would be appreciated.

A few posts back there was a recommendation to confirm your PCV system is working right. If it's not working right you could have extra pressure in the crankcase that's forcing the oil out of the weakest gasket it can find. The PCV valve is a cheap and easily replaced part. If it hasn't been changed recently, it's worth a try.

Hogwild
07-19-2012, 07:54 PM
A few posts back there was a recommendation to confirm your PCV system is working right. If it's not working right you could have extra pressure in the crankcase that's forcing the oil out of the weakest gasket it can find. The PCV valve is a cheap and easily replaced part. If it hasn't been changed recently, it's worth a try.

Going to check all of it out this weekend. I made brief check of the PCV valve and didn't notice anything out of the ordinary, but you're right, it's worth a shot for a more in depth look.

Hogwild
08-16-2012, 10:54 PM
Well it looks like I'm going to be pulling out the engine before long as my Fall project. Any suggestions as to what to be sure to replace while I have the engine out and have access? I'm going to make a list and try and do a thorough overhaul.

Grand Lake
08-18-2012, 12:08 AM
another possibility is oil blowing out the breather tube (plugged PVC valve) and running down the block.