Where did my oil go?

ShawnR

Cadet
Joined
Jul 24, 2006
Messages
15
I am a new owner of a 1990 Four Winns boat with a OMC 5.7 Cobra engine.

Prior to our maiden voyage (today) I checked the oil level and all was good. It still had new oil in it from being winterized in the fall. We rode around for about 20 minutes as an occasional knock from the engine got louder. I noticed that oil pressure had dropped to near nothing and gently idled back up to the ramp, loaded up and came home.

For those of you that will say I should have shut it down immediately, there ain't no "tow boat" on this lake.

I checked the dipstick when I got home and it is dry (no oil). There isn't any oil down below the engine or on the engine. Can the oil be discharged out through the coolant and back into the lake?

I haven't refilled yet to see just how low it is, but I have the very uneasy feeling that I will be pulling & rebuilding an engine in the next few days. I don't want another project.

Thanks,
- Shawn
 
Joined
Jul 21, 2006
Messages
19
Re: Where did my oil go?

If the knock was consistant. Do not refill the engine and run again. It might cost you even more $$$$ to fix.:'(
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Where did my oil go?

Don't just pull the dipstick out an look at it. I think this is a cause for alarm more than once lately.
When the engine is off, let it set for a minute or two. Pull the dipstick out and wipe it off. Then push it all the way back in till it hits the stop. Then pull it out and read the outcome.
It is possible to get a "Nothing on the stick" reading when first pulling it out of an engine.
 

spartanpele

Petty Officer 2nd Class
Joined
Jul 5, 2005
Messages
183
Re: Where did my oil go?

IMHO...If you had zero oil in the engine, it would have seized. You must have had something in there...at least enough to provide some sort of lubrication. Let it sit for a while and check it again. If it still runs, consider yourself lucky. As for where the oil went, your options are probably: it leaked out (check your bilge), a crack (into the cooling system), or it burned out (blow by?) Check your plugs, do a compression test, and a pressure test of the cooling system too.

btw: Always try to bring along 1-2 qts of oil with you when you venture out on the lake. Although you said there was no tow boat, it would have still been better to shut it down and paddle back then possibly run on no oil and seize the motor trying to limp back to the dock. If you have no oil pressure or pegged high temperature...shut it down.
 

fraserscrane

Cadet
Joined
May 13, 2006
Messages
27
Re: Where did my oil go?

spartanpele said:
IMHO...If you had zero oil in the engine, it would have seized. You must have had something in there...at least enough to provide some sort of lubrication. Let it sit for a while and check it again. If it still runs, consider yourself lucky. As for where the oil went, your options are probably: it leaked out (check your bilge), a crack (into the cooling system), or it burned out (blow by?) Check your plugs, do a compression test, and a pressure test of the cooling system too.

btw: Always try to bring along 1-2 qts of oil with you when you venture out on the lake. Although you said there was no tow boat, it would have still been better to shut it down and paddle back then possibly run on no oil and seize the motor trying to limp back to the dock. If you have no oil pressure or pegged high temperature...shut it down.
 

fraserscrane

Cadet
Joined
May 13, 2006
Messages
27
Re: Where did my oil go?

Hey,being in that situation before,try alway's to be prepared.Alway's throw extra oil & coolant(if necessary),into the boat.I would even get extra cooling hoses & alway's keep necessary tool's on board.If your on a lake with little tow support,you have to be prepared.Hopefully your motor did not did not run to long,with it knocking as described.If you have bad piston ring's the oil will escape through the exaust.I just bought a boat with a cracked engine block & had the motor completely rebuilt(new block)This cost $6000.00.I also had the outdrive completely gone over & a new impellor installed cost-$100.00 buck's.The impellor cool's the motor & is a cheap preventative to major issues.My boat is on a trailer& before each ride I hook up the water to the outdrive,& start the engine.Your boat engine always run's under load(pushing through the water,unlike your car)so It will not last as long - period....Alway's check your oil before you leave the shore.It takes me 10 minutes to completely check the cooling & oil systems.Install a new impellor every season,& CHANGE THE OIL regularly (next motor rebuild).IF YOUR MOTOR KNOCKS SHUT IT OFF!!.
 

ShawnR

Cadet
Joined
Jul 24, 2006
Messages
15
I may be a "little" late in updating my post....

It appears that when the previous owner said "It ran great last year", he probably forgot to mention that he never winterized it. That is my theory anyway since the block was cracked between an oil galley and the water jacket. So it pumped all the oil out into the lake on the maiden voyage.

I replaced the engine with a reman 5.7 and an still running around in the same boat 18 years later. It is now in the best shape it has been since new and I easily have $12k into a boat that is worth about $4k. Good times...
 

Grub54891

Admiral
Joined
Jun 17, 2012
Messages
6,078
Glad you got it fixed. Note to self, never take a previous owner for his word.
I just got rid of a 21’ Sylvan that I acquired for fre, no known history. The guy I gave it to,I told him that I don’t know anything about it, he checked it over, took it out on Lake Superior three times. About 60 miles total and it’s running perfect. Lucky sometimes!
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,958
I may be a "little" late in updating my post....

It appears that when the previous owner said "It ran great last year", he probably forgot to mention that he never winterized it. That is my theory anyway since the block was cracked between an oil galley and the water jacket. So it pumped all the oil out into the lake on the maiden voyage.

I replaced the engine with a reman 5.7 and an still running around in the same boat 18 years later. It is now in the best shape it has been since new and I easily have $12k into a boat that is worth about $4k. Good times...
Ayuh,..... Just 18 years late,..??........
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,681
Holy thread revival!
Those dipsticks are tricky. What I found works for a more accurate reading is to pull out the stick wait 5 min to allow the level in the tube to equalize then check it. Because with a cold engine it will often read too high with a hot engine too low. The oil in the tube needs to equalize with the level in the oil pan….
 

ejnichol

Petty Officer 2nd Class
Joined
May 28, 2002
Messages
143
Thanks for update.

May have taken a while to update but its good to know what happened to it.
It ran through my mine cracked block when reading first posts but thought maybe not since you mentioned winterized

So many posters never follow-up and update.
 

cyclops222

Lieutenant
Joined
Mar 21, 2024
Messages
1,307
Lesson to be learned about boats being ............Winterized.........or even a oil change ? Believe no one about the work they were paid to do. Always check if done. I put a black Magic Marker on parts to be changed.
Person needing a job at below minimum wages. And they have no abilities ?????
 
Last edited:

Grub54891

Admiral
Joined
Jun 17, 2012
Messages
6,078
Person needing a job at below minimum wages. And they have no abilities ?????
Ah yes. We hire people who claim to know what they are doing, but it dosent always work out. Pay is a fair amount above min wage but these people fluff their applications up a bit too much. Within a week we get them figured out and send them on their way. It's tough to find a good marine mechanic around here. Some we hire and are good will move on to a different marina in the area, and then come back as they don't like how the other one is only doing half a job. When you find a good mechanic, stick with them!
 

tank1949

Lieutenant Commander
Joined
Apr 4, 2013
Messages
1,893
I may be a "little" late in updating my post....

It appears that when the previous owner said "It ran great last year", he probably forgot to mention that he never winterized it. That is my theory anyway since the block was cracked between an oil galley and the water jacket. So it pumped all the oil out into the lake on the maiden voyage.

I replaced the engine with a reman 5.7 and an still running around in the same boat 18 years later. It is now in the best shape it has been since new and I easily have $12k into a boat that is worth about $4k. Good times...
and endless hole in the water to dump money!!!!!!
 
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