MerCruiser 470 MAJOR oil leak

[andrewjhermiz]

Hi all, first post

I have an 18' Sea Ray with a Merc 470 and I recently found an inch, no exaggeration, an inch deep of oil in the bilge. I put 5 quarts in it and after 2 hours on the water it took another 3 quarts. I have no clue where it's coming from, nothing visible of course.

Anyone experience this severe of a leak or have any suggestions? At this point anything will be appreciated.

 

[stonyloam]

Re: MerCruiser 470 MAJOR oil leak

Well with that much oil, if you can't see it leaking, probably the oil pan (maybe rusted out), check the drain plug, starboard side. check the crank seals front and back. Also check the side cover under the carburetor. Oh does it have an oil drain hose in the drain plug hole, maybe fell down into the bilge and is leaking. Good luck.

 

[Don S]

Re: MerCruiser 470 MAJOR oil leak

We can't find leaks, just tell you to look every where on the engine. With that much oil leaking, it shouldn't be hard to find.
Pull the engine cover off, fill it up with oil, start it up and keep an eye on it. If you don't see a leak go boating and have someone else drive the boat and you watch for the leak to see where it's coming from.

 

[Bondo]

Re: MerCruiser 470 MAJOR oil leak

Hi all, first post

I have an 18' Sea Ray with a Merc 470 and I recently found an inch, no exaggeration, an inch deep of oil in the bilge. I put 5 quarts in it and after 2 hours on the water it took another 3 quarts. I have no clue where it's coming from, nothing visible of course.

Anyone experience this severe of a leak or have any suggestions? At this point anything will be appreciated.

Ayuh,... Welcome Aboard,.... Leakin' like that, you ain't Lookin' hard enough,.... That's a Gusher...

 

[Scott Danforth]

Re: MerCruiser 470 MAJOR oil leak

thats not a leak, thats a hemorrhage.

you should be able so see that kind of leak without a problem

 

[andrewjhermiz]

Re: MerCruiser 470 MAJOR oil leak

Well, I guess I just have to keep looking. I don't want to have to pull the motor out either. Thanks everyone for your suggestions.

 

[DaveG55]

Re: MerCruiser 470 MAJOR oil leak

Well, I guess I just have to keep looking. I don't want to have to pull the motor out either. Thanks everyone for your suggestions.

As everyone has said, that much oil should not be that hard to find. Since many areas in the engine bay are really, really hard to see I'd suggest that you get an inspection mirror. Inspection mirrors are pretty inexpensive and can be bought with extension handles so that you can reach to tighter areas of the engine bay. That should let you search for the leak w/o pulling the engine.
Now, to repair the leak may be an entirely different story. With a leak as large as this appears to be, and with it not haveing a blatantly obvious source, it seems to me likely that the engine will have to come out to fix it...

 

[EddiePetty]

Re: MerCruiser 470 MAJOR oil leak

Hi all, first post

......... I put 5 quarts in it and after 2 hours on the water it took another 3 quarts...... .

Meaning your oil loss is probably immediately after an oil and filter change. Three quarts in two hours is likely a pressure leak.

My off-the-wall-quess is that the old oil filter gasket stuck to the block when you changed filters and now the doubled gasket has ruptured on the block side of the filter.

 

[andrewjhermiz]

Re: MerCruiser 470 MAJOR oil leak

Meaning your oil loss is probably immediately after an oil and filter change. Three quarts in two hours is likely a pressure leak.

My off-the-wall-quess is that the old oil filter gasket stuck to the block when you changed filters and now the doubled gasket has ruptured on the block side of the filter.

I checked the filter, completely white and dry. There would be oil all over it if that much was coming out.

I'm going to get one of those mirrors. That's a pretty good idea. Thanks.

 

[Sgurtin]

Re: MerCruiser 470 MAJOR oil leak

Hi all, first post

I have an 18' Sea Ray with a Merc 470 and I recently found an inch, no exaggeration, an inch deep of oil in the bilge. I put 5 quarts in it and after 2 hours on the water it took another 3 quarts. I have no clue where it's coming from, nothing visible of course.

Anyone experience this severe of a leak or have any suggestions? At this point anything will be appreciated.

I just pulled my boat out and started it up... I found the same thing? Major oil leak under the engine... Huge amount of oil built up and I had to call the drain plug to get it all out. I cannot see where the oil is coming from, or at least it's not obvious.... Did you find where your leak was coming from?

 

[andrewjhermiz]

Re: MerCruiser 470 MAJOR oil leak

I tried changing the head gasket and it helped. I still have oil loss but much, much less.

 

[shiloh87]

Oil pan, front or rear crank seal or the side inspection cover. If the cover you`d see it on the engine block, there is also an oil passage brass plug on the intake side check to see if that`s missing, other than that a crack in the block some where.