3.0 litre Mercruiser sterndrive oil issue

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Nov 21, 2021
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I recently purchased a 2005 Searay 180. I went to start it up and had no oil pressure. I checked the oil and it appeared to be empty. I filled it with 20W40 synthetic as recommended. I started the boat, the oil pressure looked fine for about 30 seconds. Then I heard a sound that sounded like a sudden pressure release and the pressur guage bottomed out. I shut off the engine, opened the engine cover anf found oil dripping from the rear of the engine. Does anyone have a clue what would be the source of this sudden release of oil under high pressure?
 

Scott06

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I recently purchased a 2005 Searay 180. I went to start it up and had no oil pressure. I checked the oil and it appeared to be empty. I filled it with 20W40 synthetic as recommended. I started the boat, the oil pressure looked fine for about 30 seconds. Then I heard a sound that sounded like a sudden pressure release and the pressur guage bottomed out. I shut off the engine, opened the engine cover anf found oil dripping from the rear of the engine. Does anyone have a clue what would be the source of this sudden release of oil under high pressure?
Was it low or empty - if completely empty I would think the engine would sound like a coffee can with rocks in it. How much oil is in bilge ?

You will have to get under or behind the engine and take some pics- depending where the oil is from it could be a few things -

where dipstick goes in the block

loose or missing oil drain plug if there is one

oil gallery plug in back of block behind flywheel may have failed or corroded. this would allow a pressurized oil passage in engine to shoot oil out of it and drain the oil pan.
 
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Thank you for your reply. My wife bought this boat and called me to come take it home. I never checked it out as she had already bought and paid for it. A couple of weeks later I went out side and started it up. It fired right up and sounded smooth and fine. But after checking the guages, I saw that I had no oil pressure. So of course I shut it down immediately. Then I bought a 5 quart jug of synthetic oil, filled it up and started it again. The guage went right up to 35 PSI at idle. But maybe 20 or 30 seconds later I heard a sudden whooshing sound, similar to pulling the hose loose from a compressor. So I shut it down and lifted the hood over the engine and found oil dripping off the rear transom area as well as the hoses behind the engine. I just got home from work and it;s getting dark out so I will have to get some pictures tomorrow to attatch to this thread but maybe I've given you something more to consider. Again, thank you very much.
 

kenny nunez

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If the oil filter was rusted badly enough that may be what made the noise you heard when it blew out.
 

Grub54891

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If the oil filter was rusted badly enough that may be what made the noise you heard when it blew out.
I was just thinking the same thing. Even a good filter can blow the gasket if tightend incorrectly, or double gasket.
 
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I put the whole jug in because it was dry. That rusty oil filter was a good thought. I'll have to check it tomorrow.
 

Scott06

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Thank you for your reply. My wife bought this boat and called me to come take it home. I never checked it out as she had already bought and paid for it. A couple of weeks later I went out side and started it up. It fired right up and sounded smooth and fine. But after checking the guages, I saw that I had no oil pressure. So of course I shut it down immediately. Then I bought a 5 quart jug of synthetic oil, filled it up and started it again. The guage went right up to 35 PSI at idle. But maybe 20 or 30 seconds later I heard a sudden whooshing sound, similar to pulling the hose loose from a compressor. So I shut it down and lifted the hood over the engine and found oil dripping off the rear transom area as well as the hoses behind the engine. I just got home from work and it;s getting dark out so I will have to get some pictures tomorrow to attatch to this thread but maybe I've given you something more to consider. Again, thank you very much.
Yeah take some pics. Agree with guys on corroded or poorly installed filter but that is on front left of a 3.0…remote filter would be in same spot.

power steering hoses go back there but wouldn’t affect oil pressure on engine. Hoepfully u shut it down soon enough to not damage engine .
I assume the oil you put in engine is now gone and dipstick is dry ?
 

Scott06

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I put the whole jug in because it was dry. That rusty oil filter was a good thought. I'll have to check it tomorrow.
the complete oil capacity of this engine is 4 qts with the filter. Would second other comments that it may be over full now.
 
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Today, I actually found the leak and I'm sure you would agree that the dipstick wasn't lying. I added more oil to what was shown to be empty on the dipstick. I had an assistant start the engine while I positioned myself over the engine watching for where the oil was blowing out. I found out that the 1/4" nipple that feeds the oil pressure guage and anpther sending unit that I don't know for what, was cracked and squirting a lot of oil under pressure right at the brass tee which exits the engine directly above the starter and just under the solohoid My next issue will be trying to find a way to extract the broken nipple from the engine block. I need to come up with an extracter of sorts that will bite into the outside of the nipple and allow me to unscrew the nipple.
 

Scott06

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Today, I actually found the leak and I'm sure you would agree that the dipstick wasn't lying. I added more oil to what was shown to be empty on the dipstick. I had an assistant start the engine while I positioned myself over the engine watching for where the oil was blowing out. I found out that the 1/4" nipple that feeds the oil pressure guage and anpther sending unit that I don't know for what, was cracked and squirting a lot of oil under pressure right at the brass tee which exits the engine directly above the starter and just under the solohoid My next issue will be trying to find a way to extract the broken nipple from the engine block. I need to come up with an extracter of sorts that will bite into the outside of the nipple and allow me to unscrew the nipple.
If some of the nipple is sticking out put a set of vice grips on it. Otherwise use a screw extractor or easy out on it
 
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I tried 2 different easy outs on it but neither one could break the nipple loose. They are both inside, reverse thread tools but cant seem to get a good bite on the brass nipple. I need to find a good pinch style easy out and I'm sure that I own one as I have virtually every tool imaginable in my shop but I'll be damned if I know where I put it. The style I;m talking about looks like a gear within a pinion that you slip over the nipple and attach a ratchet and extension to it and when you crank it, the teeth pinch into the nipple and bites down on it while you turn and break it loose. My question is why do I have 2 sending units on this tee? I know one is for reading the oil pressure to the guage but the other looks much different like perhaps an oil temperature guage, but I don't have an oil temp guage on the dash.
 

Scott06

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I tried 2 different easy outs on it but neither one could break the nipple loose. They are both inside, reverse thread tools but cant seem to get a good bite on the brass nipple. I need to find a good pinch style easy out and I'm sure that I own one as I have virtually every tool imaginable in my shop but I'll be damned if I know where I put it. The style I;m talking about looks like a gear within a pinion that you slip over the nipple and attach a ratchet and extension to it and when you crank it, the teeth pinch into the nipple and bites down on it while you turn and break it loose. My question is why do I have 2 sending units on this tee? I know one is for reading the oil pressure to the guage but the other looks much different like perhaps an oil temperature guage, but I don't have an oil temp guage on the dash.
Likely the second one is the oil pressure switch. The alarm that sounds briefly when you start is because there is no oil pressure yet until the engine gets going.
same alarm sounds for low oil pressure, low drive lube, or engine over heat.
the alarm should have sounded when you lost oil pressure. Switch should open at 4 psi, i think it closes a connection to ground when it alarms

you may be able to try a left hand drill bit to get it out ?
 

kenny nunez

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Go to a contractor style plumbing warehouse or if you have a plumber friend. They will have the correct extractor. Probably the smaller sender was for a light on the instrument panel or a alarm like Scott06 described that lets you know the ignition is on and the engine is either not running or out of oil pressure. Not all boats have the light. 1/8” npt should be the fitting size.
 
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That makes perfect sense and I do recall hearing a buzzing alarm sound just as I was shutting it down when the pressure dropped. Thank you.
 

Scott Danforth

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I tried 2 different easy outs on it but neither one could break the nipple loose. They are both inside, reverse thread tools but cant seem to get a good bite on the brass nipple.

Hammer it in. Use a combo of the easy out and a vicegrips if its tight

If that doesnt work, may have to use a thin air saw blade or drill it out (use a good shop vac while drilling to get the chips)
 
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