Oil everywhere

Tlgtrans

Cadet
Joined
Jul 10, 2022
Messages
6
I changed the oil and filter in my mercruiser 5.7 today-ran it for about 20 min in the lake, oil pressure was about 70 at operating temp, 3500 rpm. All of a sudden, oil pressure went to zero, I shut that engine off, got back to the dock with other engine. Opened the engine compartment, oil everywhere. Filter still tight, I’m at a loss on this one. Any ideas?
 

itsathepete

Petty Officer 1st Class
Joined
May 23, 2018
Messages
300
Could be any number of things. Oil filter defective and leaking, oil filter o-ring bad, not tight enough, oil cooler line leak, oil drain plug leak. you will have to do some looking. hopefully you got it shut down in time to save the engine
 

SternDriveEd

Seaman Apprentice
Joined
Mar 1, 2022
Messages
39
When you removed the old oil filter did the gasket seal stay on the engine block? If so, there will be two stacked gaskets on the new filter once installed. This will quickly lead to a catastrophic oil loss.
 

Tlgtrans

Cadet
Joined
Jul 10, 2022
Messages
6
Could be any number of things. Oil filter defective and leaking, oil filter o-ring bad, not tight enough, oil cooler line leak, oil drain plug leak. you will have to do some looking. hopefully you got it shut down in time to save the engine
I shut it down after about 5 seconds. Didn’t hear any clanging or weird noises. I checked the filter again, was tight. I’m going to wash the engine down and look around. Other engine ran fine. Never seen this before
 

Tlgtrans

Cadet
Joined
Jul 10, 2022
Messages
6
When you removed the old oil filter did the gasket seal stay on the engine block? If so, there will be two stacked gaskets on the new filter once installed. This will quickly lead to a catastrophic oil loss.
I don’t think so-I wiped off the housing and didn’t see one but then again, wasn’t really paying attention. I checked for leaks after changing on idle, didn’t see any
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,694
Do you have remote oil filter mounts? Hoses OK? These are really convenient but they can leak.
 

Drcoffee

Petty Officer 1st Class
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Aug 26, 2021
Messages
220
Can I ask, Do you always see 70#? 70psi sounds high for oil pressure. 40# is what I see at 2500rpm. You may have blown a seal at that pressure. Consensus on google is 10psi for every 1000rpm
 

Tlgtrans

Cadet
Joined
Jul 10, 2022
Messages
6
Can I ask, Do you always see 70#? 70psi sounds high for oil pressure. 40# is what I see at 2500rpm. You may have blown a seal at that pressure. Consensus on google is 10psi for every 1000rpm
Yes, it’s always been about that-on idle usually around 25 so I believe that might be a sending unit problem or a gauge problem.
 

Drcoffee

Petty Officer 1st Class
Joined
Aug 26, 2021
Messages
220
Check the oil filter. It might have collapsed, blocking oil flow.
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,369
I changed the oil and filter in my mercruiser 5.7 today-ran it for about 20 min in the lake, oil pressure was about 70 at operating temp, 3500 rpm. All of a sudden, oil pressure went to zero, I shut that engine off, got back to the dock with other engine. Opened the engine compartment, oil everywhere. Filter still tight, I’m at a loss on this one. Any ideas?
Oil pressure senders can break and cause catastrophic oil loss. Ask me how I know...
 

tank1949

Lieutenant Commander
Joined
Apr 4, 2013
Messages
1,894
I changed the oil and filter in my mercruiser 5.7 today-ran it for about 20 min in the lake, oil pressure was about 70 at operating temp, 3500 rpm. All of a sudden, oil pressure went to zero, I shut that engine off, got back to the dock with other engine. Opened the engine compartment, oil everywhere. Filter still tight, I’m at a loss on this one. Any ideas?
I bet you left old O ring on block. Or, blew Oil Pressure switch.
 
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