Where did my oil go?

ShawnR

Cadet
Joined
Jul 24, 2006
Messages
14
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!!.
 
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