Volvo 8.1 Gi No Oil

Hi newbie looking for some advice...

I’ve got twin, fresh water cooled, 2004 Volvo Penta 8.1 Gi which was serviced less than 5hrs ago.

Recently while cruising I looked down at the oil pressure gauge and it was showing 0psi (at 3600rpm) but there was no alarm!! Thought it might just be a faulty pressure sender but stopped the engine and checked the dipstick anyway... No oil!

Limped back to closest marina on one engine and filled crankcase with about 8 Litres of oil. Started the engine and pressure came up to normal but did note a bit of an oil sheen off the stern. Assumed I have an oil leak somewhere (not into the bilge or closed water cooling system) but after only a very short run (3mins at about 2200rpm) pressure dropped to zero again. No Alarm, no rough running, no smoke but did hear some tappet noise this time (because I was listening for it). Stopped, checked dipstick, empty again! No milky oil - just nothing on the dipstick. Suspected that my oil cooler has a hole, causing oil to pump straight into the raw water cooling. Did the rest of the trip on one engine.

When I finally got back home, the dipstick showed there was water in the crankcase but no oil. Pumped out the crankcase and about a litre of water came out but very little oil. There’s no evidence of any oil in the closed cooling water. Where can 8L of oil go in less than 3mins. Pulled the oil cooler but it doesn’t seem to have any holes in the cooling tubes (I will have it pressure tested).

Does anyone have any suggestions of what else could cause it to dump that much oil (must be into the raw water system) that quickly? Do any of the oil galleries get close to any raw (not fresh) water galleries in manifolds, head or anywhere else?

only place is the oil cooler or a hole in a piston blowing it out the exaust valve

With no rough running and no excessive smoke...... I would look towards the engine oil cooler.
Engine oil pressure is greater than the seawater system pressure, so that would explain how a leak here would deplete engine oil capacity.
Once oil pressure diminishes, seawater pressure would now become greater and could enter the oiling system.


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Thanks guys, my thought too, that’s a lot of oil to dump so quickly. Can’t think of anywhere else it could go...

Took the cooler out and all the water cores all looked clean - probably because the mechanic did a system flush at the recent service (if I blocked one side and blew through the other, there wasn’t any obvious leak). Oh well, sent to workshop for proper pressure test. I’ll let you know what they find.

Raft61, you have another possible issue to resolve.... and that would be any potential damage that may have been caused by running this engine with no oil.

I doubt there is any potential damage, it's an absolute certainty. What happens when you run an engine with water mixed with the oil is that the babbit material on the bearing shells gets eaten off in a matter of minutes. Your engine will require a full rebuild at minimum but probably is more cost effective to prepare yourself for a new engine there. It may be possible to save it if the damage is limited to the bearings but labor to repair is about the same as replacement. Hope it's not too painful.

Re: alarm. If there was no alarm, there should be a low-oil shutoff switch that will kill the engine when pressure drops below 8 psi. Be sure that that circuit is present and working. Also, if water was getting in, the oil pump would not know the difference and happily continue to pump emulsion and not oil. Thus the death of an 8.1 Gi.

No disagreement at all.

Yep... preparing for the worst. Can’t understand why the oil pressure alarm/cut-off didn’t activate (And pissed off that it didn’t - maybe an insurance claim?).

Are there three different sensors/switches for the low oil alarm, the 8psi engine cut-off and the pressure sender (for the oil pressure gauge). I know where the pressure sender is but where are the other switches located on the 8.1 Gi?

It was probably making pressure but with an emulsion of water and oil mix, thus no alarm

Hi o2batsea,

Don't think so, pressure guage was at zero, nothing on dipstick (no oil, no emulsion, no water). Yet no alarm or engine shut down!

The water didn't enter until sometime after the engine was stopped (maybe 8hrs later). And even then it wasn't an emulsion when I pumped it out, just clear water (about 1 litre of water with just a capful of clean oil floating on top).

Got the pressure Test results. Three tubes started leaking when pressure reached about 10psi.

Now I know where 8 Litres of oil went... Need to rename my boat Exon Valdez!

Is it worth putting a new cooler on, refilling it with oil & trying to start it? Or just pull engine out?

...........................

Raft61 said:

Hi o2batsea, Don't think so, pressure guage was at zero, nothing on dipstick (no oil, no emulsion, no water). Yet no alarm or engine shut down!
In addition to the ZERO oil pressure NOT causing an alarm, the ZERO oil pressure should have opened the fuel pump circuit.



Is it worth putting a new cooler on, refilling it with oil & trying to start it? Or just pull engine out?
Not much to loose by trying.
You'll need to replace the oil cooler anyway.
The rest will cost you your time and new oil and filter only.

Click to expand...

Let us know what happens...I always carry about a gallon of oil onboard because things like this happen.

Hey Lou,

Got the new Oil Cooler. Will definitely let you know how it goes (hoping for the best but preparing for the worst...)

I used to talk with you on the Four Winns Forum where I had a Sundowner with a 5.0L Mercruiser. Got to know that engine quite well (thanks to your advice help). Into a 42’ Mustang with twin VP 8.1L Gi now... learning everything VP.

All the best - Ric

Most boats I service with raw water cooled oil or transmission coolers get a pressure switch tied into the ign to kill the engine when oil pressure goes to 0

Well time to raid the bank account...

Refitted the new oil cooler and filled sump with oil. Engine started ok seemed to run smooth but there was a very loud “clack... clack.... clack...” sound (absolutely no idea what’s making that much noise? Seized valve, collapsed bigend bearing, broken rod?).

Anyway I shut it down pretty quickly (not that I’d do much more damage than is already done) but Oil pressure had come back... certainly sounds terminal and expensive. Time to pull the engine and either rebuild or repower.

No water in the oil, no oil sheen in exhaust, no water in the cylinders (best as I could tell by removing the plugs). Now VERY annoyed that the oil pressure alarm/engine cutoff didn’t work!

Raft61 said:

Well time to raid the bank account...

Refitted the new oil cooler and filled sump with oil. Engine started ok seemed to run smooth but there was a very loud “clack... clack.... clack...” sound (absolutely no idea what’s making that much noise? Seized valve, collapsed bigend bearing, broken rod?).

Anyway I shut it down pretty quickly (not that I’d do much more damage than is already done) but Oil pressure had come back... certainly sounds terminal and expensive. Time to pull the engine and either rebuild or repower.

No water in the oil, no oil sheen in exhaust, no water in the cylinders (best as I could tell by removing the plugs). Now VERY annoyed that the oil pressure alarm/engine cutoff didn’t work!

Click to expand...

This is an old thread, but thought I would add that ABYC does not recommend a system that automatically shuts down the propulsion engine for low oil pressure or overheating like you normally find on a generator. The reason is you might be right in the middle of something very important (avoiding swimmers, being blown into the rocks, etc.). However, having a properly working audible/visual alarm system is a must and then you can decide if it’s safe to shut down. Also I know the original topic is oil, but the alarm system uses the same buzzer and loosing an impeller is probably more common and can be just as catastrophic. Most older engines monitor the cooling water temp (both raw water and closed coolant type) to activate the alarm. It’s better to monitor exhaust temps just after the elbows where it mixes with the raw cooling water because the exhaust overheats much faster than waiting for the block to heat up.