High oil pressure Volvo AD31P

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banflu1

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Hi all,

Last Sunday while cruising back to the marina (3300 rpm) I noticed that the oil pressure on the Port engine was climbing from the usual 60 psi. I kept my eye on it and once it crept over 90 I got the boat off the plane back to idling speed. Oil pressure dropped to normal levels but remained a tad higher than the Starboard engine. I put the boat slowly back on plane and now the oil pressure went up to 75 psi and stayed there. I was only around 10 mins out.
Once berthed I checked the engines and found oil under both of them. I can’t understand where (or if) oil came out of the starboard side, but for sure oil came out of the Port engine from multiple places. Oil level now is slightly higher than Minimum.

I got my mechanic to check (I trust him, he is experienced); he checked the oil (it looks fine, only got 20 hours on it), replaced the oil filter (barely any change), and now is suspecting that one of the oil release valves is not working well. He said that there are two in the oil cooler and another one inside the oil pump.

He has now ordered the ones in the oil cooler and plans to replace them this week; but he said that if the issue remains the same, it’s an engine out job so bye bye summer 😟

Does anyone have any other ideas what could be wrong / what we can check?

As a brief history, I’ve had the boat for 2 years and have maintained it well in this time, frequent oil changes etc. The oil is nice and clean when I change it; it doesn’t go black immediately.
 
Could be blowby pressurising the sump which would be compression test then surgery depending on results

or the oil link pipe from the head to the rocker shaft which has small rubber seal in the head could have split or moved

or relief valves sticky
 
Your mechanic is probably right. The regulator valves in the filter housing are easy to check and a relatively quick fix. Get those done and change the oil filter while you are at it.. Often just a busted spring.
 
penfold said:
Have the gauges been swapped or a separate gauge been used to verify what the actual pressure is?
Click to expand...
No, but the port engine clearly shows it was leaking oil so it makes sense.
Also, the indicated oil pressure is ‘normal’ at idle.
Still, my mechanic said he’ll get a mechanical gauge when he comes.
 
Back in 1997 we had a brand new Sealine S37 delivered. A year later at 60 hours it was serviced in time for a trip to Guernsey. The boat ran fine, but checking the engine levels (Mercruiserl to return home, found a large amount of oil in the bilge under both engines. Checked the oil to find it was still a couple of inches over the dip stick full level. Turns out the service engineers had overfilled the oil and the pressure blew both rear main crankshaft oil seals. Both engines had to be removed and repaired, took 8 weeks. Ran perfectly well after that!
 
nicho said:
Back in 1997 we had a brand new Sealine S37 delivered. A year later at 60 hours it was serviced in time for a trip to Guernsey. The boat ran fine, but checking the engine levels (Mercruiserl to return home, found a large amount of oil in the bilge under both engines. Checked the oil to find it was still a couple of inches over the dip stick full level. Turns out the service engineers had overfilled the oil and the pressure blew both rear main crankshaft oil seals. Both engines had to be removed and repaired, took 8 weeks. Ran perfectly well after that!
Click to expand...
Wow that must have been a nightmare!

Hopefully no damage was done in my case.. Will update soon I hope
 
good morning. my mechanic replaced the 2 relief valves in the oil filter housing, but the pressure seems to have remained the same.
he said he could not check with a mechanical gauge as the oil pressure sender is stuck and he couldn't remove it.

i switched over the oil pressure gauges and i'm getting the same readings. i'm aware the sender might be giving the wrong info but i doubt it.

as a next time i was going to use an engine flush (liqui moly engine flush plus), as an attempt to remove any blockages should this be the case. if this fails, i am stumped to be honest :/
 
Sorry if I’ve missed it. Have you tried taking the sender out for a blow out and clean ? Had a similar issue with a pressure switch
 
jrudge said:
Given the engine was leaking oil a faulty sensor is not that likely
Click to expand...
Totally forgot about the mention of it leaking oil too.
Got to be a restriction causing it. Oil cooler, turbo feed pipe (hopefully not because of turbo bearing issues throwing shrapnel through the oil system).
 
Drain it measure the vol .Check this against spec . Also check for water contamination
Refill it with manufacturers vol .
Check blow by putting hand over open rocker box ( oil fil hole ) compare both engines at idle and revs .It’s pressure just on the palm of your hand .= report back if equal or greater ?

As for leaks if it’s been overfilled inadvertently it’s blown a lot of seals from it long / hot cruise , not something your mechanics gonna be proud of .See post #8 .Or it’s fractured a ring and = blow by as post #3 .

How many hrs btw ?
 
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With sensor ( any btw ) you can get hold of voltage/ resistance values and connect a voltmeter to check the range .
With this simply compare values of both sides if they more less identical then it’s not the stuck sensor .


If the injectors are removed and examined or while they are out look inside with a borescope …..you will find the fractured ring cylinder (s) ? They will be blacker , sooted up more look very different from normal ones .

Thirdly left of field but worth a mention on cars I heard a batch of oil filters collapsing ( not OEM s = cheapo copied from you know where ) ?This can cause spurious oil P issues not unlike this .So Q what filters have been used ? Any cost cutting by any chance ?
 
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Portofino said:
Drain it measure the vol .Check this against spec . Also check for water contamination
Refill it with manufacturers vol .
Check blow by putting hand over open rocker box ( oil fil hole ) compare both engines at idle and revs .It’s pressure just on the palm of your hand .= report back if equal or greater ?

As for leaks if it’s been overfilled inadvertently it’s blown a lot of seals from it long / hot cruise , not something your mechanics gonna be proud of .See post #8 .Or it’s fractured a ring and = blow by as post #3 .

How many hrs btw ?
Click to expand...
It’s good that you mentioned this.. because this is another strange thing.
Both my engines only take around 6lt of oil. The manual says 9lt.
I had asked about it on this forum last year and if I recall well I was told it may be because the engine might be tilted backwards.
I drain them.. only around 6lt comes out. I fill them to between min and max.. around 6lt.
 
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