1989 4.3 mystery oil leak :-(

moparron

Seaman
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Jan 22, 2015
Messages
52
Howdy.. I recently purchased an 89 Regal sebring 195XL CC. Boat is not perfect... Hell it's an older boat. I expected that. What does get me.. is a friggin mystery oil leak. The first time we took it out - as a shake down to make sure things worked and such. everything seemed fine until we got back on the trailer and I pulled the drain plug... looked like oil mixed with the bilge water.
Got home, and yup.. oil in the bilge :-( Made sure everything was tight, oil level was still full. So I figured that when the previous owner changed the oil he spilled some in the bilge and didn't clean it up properly. Still.. I checked oil drain plug, oil filter, oil pan bolts, etc.. everything seemed fine
Took the boat out this last Sunday(was 80 here in Florida). Having a good ol time on the boat. We decided it was time to head in, so got the boat out in the channel and cruising at about 30MPH. soon I noticed that the oil pressure was a bit too low for my liking.. when we went out, It was reading about 50PSI at 3800 rpm. Now it was reading 20 at 3900 RPM. Shut it down, pulled the dipstick.... nothing!!! Darn glad I had a little voice tell me "bring oil... just in case". Three quarts later and it was full again. Bilge was full of oil (Shut off pump - as not to pollute anything)

Got home... drained bilge into 5 gallon bucket. and started looking for the leak. Checked the usual culprits from what I found on a bunch of forums. Not the front seal, not the timing cover (that would be just too easy). Starboard side of the motor is soaked, wires tot he starter are soaked, motor mount is soaked. Oil pan gasket appears dry?? Dipstick tube is tight and not moving in or out. No PCV valves... just breather tubes (again - a stuck PCV would have been too easy).

Any ideas on where to check next?? Or do I need to figure out how to get my engine hoist in the boat and yank the motor??? The motor was "freshened up" about 75 hours and four years ago.
 

Alumarine

Captain
Joined
Feb 22, 2005
Messages
3,684
Welcome. Sorry for your trouble. What motor is it?
They're not hard to pull btw. Probably wouldn't use an engine hoist in the boat though.
 
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Bondo

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70,468
Howdy.. I recently purchased an 89 Regal sebring 195XL CC. Boat is not perfect... Hell it's an older boat. I expected that. What does get me.. is a friggin mystery oil leak. The first time we took it out - as a shake down to make sure things worked and such. everything seemed fine until we got back on the trailer and I pulled the drain plug... looked like oil mixed with the bilge water.
Got home, and yup.. oil in the bilge :-( Made sure everything was tight, oil level was still full. So I figured that when the previous owner changed the oil he spilled some in the bilge and didn't clean it up properly. Still.. I checked oil drain plug, oil filter, oil pan bolts, etc.. everything seemed fine
Took the boat out this last Sunday(was 80 here in Florida). Having a good ol time on the boat. We decided it was time to head in, so got the boat out in the channel and cruising at about 30MPH. soon I noticed that the oil pressure was a bit too low for my liking.. when we went out, It was reading about 50PSI at 3800 rpm. Now it was reading 20 at 3900 RPM. Shut it down, pulled the dipstick.... nothing!!! Darn glad I had a little voice tell me "bring oil... just in case". Three quarts later and it was full again. Bilge was full of oil (Shut off pump - as not to pollute anything)

Got home... drained bilge into 5 gallon bucket. and started looking for the leak. Checked the usual culprits from what I found on a bunch of forums. Not the front seal, not the timing cover (that would be just too easy). Starboard side of the motor is soaked, wires tot he starter are soaked, motor mount is soaked. Oil pan gasket appears dry?? Dipstick tube is tight and not moving in or out. No PCV valves... just breather tubes (again - a stuck PCV would have been too easy).

Any ideas on where to check next?? Or do I need to figure out how to get my engine hoist in the boat and yank the motor??? The motor was "freshened up" about 75 hours and four years ago.

Ayuh,.... Welcome Aboard,..... Oil, like water, flows Downhill,.....

Keep lookin' higher til there's No oil, 'n ya just went by the leak,.....

Sounds like maybe the valve cover,.....

Pull the manifold to get a better look,...
 
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moparron

Seaman
Joined
Jan 22, 2015
Messages
52
I would welcome valve cover gaskets.. I think? New to power boating, not new to motors. And the manifold assembly looks a bit daunting (but probably isn't). I assume there are super special exhaust gaskets that have to be hand made by some blind lady on the top of mount Everest? Not like a trip to my local O'Riellys could cure?
 

Bondo

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I would welcome valve cover gaskets.. I think? New to power boating, not new to motors. And the manifold assembly looks a bit daunting (but probably isn't). I assume there are super special exhaust gaskets that have to be hand made by some blind lady on the top of mount Everest? Not like a trip to my local O'Riellys could cure?

Ayuh,.... For the manifolds, I like the carbon metallic type gaskets,...

I get 'em from Merc. for the riser joint,....

For the head surface, I'm sure Fel-pro makes a one piece metallic gasket, but I don't have the number, for the V6,...
Ya need the one piece, as the automotive are individual ports, 'n ya can't hold 'em in-place to mount the manifold,...

For the valve cover, ya can't beat the new sillicone rubber ones,....
 

Watermann

Starmada Splash of the Year 2014
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3 quarts is a bunch of oil to loose in one day and not be able to find where it is oil soaked and isn't. Gravity is a huge help as oil won't go up. How about the gasket where the fuel pump mounts on right front of motor?
 

Fun Times

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That's a good thought Watermannon the fuel pump gasket. 3 quarts is a lot of oil. There should be two gasket there at the pump. < Maybe it was missed since the engine is kind of fresh...Hopefully it's something easy like the valve cover. Did you check the rear of the engine area for oil as well?

Here's some OEM part numbers to start looking into.
FUEL PUMP AND FUEL FILTER
CYLINDER HEAD AND ROCKER COVER
EXHAUST MANIFOLD AND EXHAUST ELBOW
http://www.mercruiserparts.com/selectSerailRange.asp?doc_nbr=4.3L++(2+BBL.)++++GM+262+V-6++1988-1992
 

moparron

Seaman
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Jan 22, 2015
Messages
52
I will check the fuel pump gasket - that should be easy enough.
Yes, Three quarts of oil is a lot... believe me I know.
 

Watermann

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The fuel pump is almost directly above that motor mount where you saw oil so hopefully that's the culprit or something else easy to repair and your're off to having fun with your new boat!
 

moparron

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Jan 22, 2015
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No Title

okay... fuel pump does not appear to be leaking? got less than a quarter turn on all three bolts. Rechecked oil pan... got about a half a turn on each bolt, valve covers.. port side (where there appears to be the most oil) a little more than a turn, starboard side - two turns on outside, four turns on the middle. I don't see any oil between the valve covers and either manifold. Checked the rear of the motor.. it's a bit slimey, but not soaked (and I found another grease fitting - bonus).
Now, in my search of forums I have heard there are certain bolts that need to be in place (one in front of fuel pump). I ran solid core wire into these holes and they do not appear to go through the block - so is this a tale? There is also a bolt hole below the head above the dipstick tube. (see attached pics)
 

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grewvin1

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When you checked the oil pan did you check the pan its self? they can rust out and all you need is a pin hole hidden by cluster raised (blister) corrosion to leak out. Just a thought have seen it before.
 

Fun Times

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The two bolt holes at the front of the engine would be where you'd mount a engine mounted sea water pump and I'm pretty sure the little hole by the starter is where you'd mount the starter brace. Item # 3 & 5, STARTER MOTOR AND ALTERNATOR
 

airshot

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Sounds like it leaks when running, so....when it is running have someone else pilot the boat and git your nose in there and look around. A leak that big should be fairly easy to locate but it probably needs to be running hard for it to really leak..
 

flipbro

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Feb 8, 2013
Messages
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Just because you cant get a full turn on a bolt or you can get four full turns isnot a real way of ruling things out gaskets do get brittle after years. Especially old cork.. im with bondo you need to get a good look at the valve covers. If need be pop the valve covers and reseal then its rulled out and its cheap..
 

m_steiger

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Jun 25, 2013
Messages
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Ive seen on my boat where blowby pressure builds in the crankcase and forces the oil out of the dipstick tube and the drips into the bilge. My fix was putting valve cover breathers on both side instead of the tubes running to the flame arrestor.
 

Bondo

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Just because you cant get a full turn on a bolt or you can get four full turns isnot a real way of ruling things out gaskets do get brittle after years. Especially old cork.. im with bondo you need to get a good look at the valve covers. If need be pop the valve covers and reseal then its rulled out and its cheap..

Ayuh,.... 'n it seems to be forgotten, that the leak is ABOVE the spill,....

There's no fan whippin' the air on a boat motor,....
Gravity says the oil mess is Below the leak, not ahead of, nor behind the leak,...

'n, Yes, tightenin' the bolts, don't fix a ripped/ distorted gasket,....
Removal, 'n replacement does,....
 

moparron

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Jan 22, 2015
Messages
52
OHC... "There is no fan whippin' the air on a boat motor" - I had not actually thought about that! Since everything is covered to some degree in a layer of slime I just mentally pictured a fan spaying oil particles everywhere! Seriously... it seems like someone loaded up a paint gun with oil and sprayed everything - just to make tracking this leak down that much more difficult.

The oil pan does not appear to have rust holes in it - it actually appears quite new (like maybe it was replaced with the freshen up?)

The idea of yanking the valve covers no matter what doesn't seem like a bad idea... it will give an initial peak into the motor, check out the valve train, and yes - then I can rule them out. Also plan on spraying the motor down with brake clean - just to get the slimey residue off, and remove what oil is still clinging to the motor off - to aid in future oil hunting. But I really need the rain to stop before I brake clean the motor - since I want to open the boat up to air when I do that :)

I am also thinking about doing another compression test.... just to be sure I don't have a serious blow by issue causing all of this, ya know in case i broke something on the very first trip?
 

Bondo

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70,468
OHC... "There is no fan whippin' the air on a boat motor" - I had not actually thought about that! Since everything is covered to some degree in a layer of slime I just mentally pictured a fan spaying oil particles everywhere! Seriously... it seems like someone loaded up a paint gun with oil and sprayed everything - just to make tracking this leak down that much more difficult.

The oil pan does not appear to have rust holes in it - it actually appears quite new (like maybe it was replaced with the freshen up?)

The idea of yanking the valve covers no matter what doesn't seem like a bad idea... it will give an initial peak into the motor, check out the valve train, and yes - then I can rule them out. Also plan on spraying the motor down with brake clean - just to get the slimey residue off, and remove what oil is still clinging to the motor off - to aid in future oil hunting. But I really need the rain to stop before I brake clean the motor - since I want to open the boat up to air when I do that :)

I am also thinking about doing another compression test.... just to be sure I don't have a serious blow by issue causing all of this, ya know in case i broke something on the very first trip?

Ayuh,.... I suggest ya find a motor cleanin' soap or spray,.... Brush down what ya can, 'n flush it off with a hose,....

Brake Clean is pretty nasty ship,...

There ain't that many places it can come from,....

Clean it up, run it, 'n look Closely,.....
Valve covers, intake manifold, distributor,..??
 

Watermann

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To clean up that mess I would use super clean and a pressure washer so there isn't so much water volume. The super clean will also clean up the bilge too. The super clean won't ruin any of the wiring, hoses or your interior.

product_degreaser.jpg
 
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