Extremely high oil pressure

[Marian Claire]

Are you asking about the oil pressure adjustment?
Dan S/V Marian Claire

[Bingy]

Yes
When I was loosening the nut I could feel the whole body coming out I believe.
Ability to see clearly is limited due to bulkhead which is very close to engine.

[Marian Claire]

Cool. That is not unusual. Some times the, I do not know the exact names, threaded part comes out with the nut. When you have it out you can clean it up and clear the threads so they move independently later.. Nothing SHOULD pop out if the engine is off. I have an early model and I use a magnet to pull out the spring/cone assembly. Suggest you put down rags to catch anything the falls. The MC is very assessable but yours may be different. Your access is limited so go slow. OOOMMMMM
Dan S/V Marian Claire

[Bingy]

Will try to remove tomorrow and inspect and clean.
Hopefully it is only stuck or dirty.
Thanks for the help.
Will report back.

[Marian Claire]

Bingy: You may already have this but this link shows the two types of oil pressure adjusters. http://www.moyermarine.com/oil_pressure.htm
Dan S/V Marian Claire

[Administrator]

A matter of intellectual curiosity from the peanut gallery:

What is the mechanism(s) by which an A4 which was formerly running at a proper oil pressure would somehow climb to levels like this?

I'm thinking false positive.

Bill

[joe_db]

We did suggest trying another gauge, preferably a mechanical one.

[ndutton]

What is the mechanism(s) by which an A4 which was formerly running at a proper oil pressure would somehow climb to levels like this?l

Is this a general question or is it related to this thread? Crazer in post #1 said his oil pressure has always read high since he's owned the boat. Bingy in post #13 said he is dealing with low oil pressure.

To attempt to answer the question though, the only thing that comes to mind is a stuck (closed) pressure adjustment valve. It's a pressure relief and if it's not relieving . . . . .

[romantic comedy]

I think most systems are similar. The pump is driven by the engine. It just pumps the oil into the gallery. With no relief valve it would build to whatever pressure it would build to. This would vary with engine speed and oil viscosity.

In its travel, the oil comes first to the pressure relief valve. This valve is there to maintain a steady oil pressure, regardless of engine speed or oil viscosity. This valve is just a ball pushed into the gallery by a spring. It maintains pressure by bleeding off oil, and sending it back to the crankcase.

Low pressure could be caused by the oil pump not being able to pump enough oil. (maybe due to wear, or thin oil) Of course if the bearings have too much tolerance, that would cause problems too.

High oil pressure can be caused by the valve not bleeding off the oil.

[Bingy]

I changed oil today, Rotella 15 w 40.
Removed needle valve and spring on oil pressure regulator.
Cleaned and re-installed .
Adjusted to 42 PSI at 1800 RPM ,water temp 160.
I assuming all is well and will monitor for awhile.
Thank You All

[Administrator]

To attempt to answer the question though, the only thing that comes to mind is a stuck (closed) pressure adjustment valve. It's a pressure relief and if it's not relieving . . . . .

So the oil pump is capable of such pressure if the pressure adjustment is closed?

Bill

[ndutton]

So the oil pump is capable of such pressure if the pressure adjustment is closed?

I'll give a qualified yes. It depends on the bearing tolerances and/or wear. I once had a Ford F-250 with a 390 engine. For some reason the oil pressure relief valve stuck closed. The first symptom was the spin-on oil filter ruptured within 5 seconds of starting the engine. Come to think of it, after replacing the filter the second symptom was a repeat of the first.

I was a slow learner.

[hanleyclifford]

I once spun an A4 on the hard with relief valve two blocked (only for a few seconds) - saw 125 psi .

[Administrator]

Wow! Well, that answers that question.

Bill

[Crazer]

I'll assume electric sender and gauge. It seems your sender is shot. These senders are similar to a mechanical gauge, but instead of a needle they have an electrical wiper that contacts a resistance coil wound on an arc shaped piece of fiberglass. Guess what - the resistance coil wears out! Wiper is always rubbing in the same spot.
Fix? First, get a mechanical gauge, 1/8" NPT and screw it into the hole in the side of the block. Read oil pressure on the new gauge. If it's a good number, get a new sender. If it's still 80 psi, let us know and we'll advise further.

So, just to be clear, installing a mechanical gauge is simple matter of screwing into the location currently occupied by the sending unit? I'll pick one up at Autozone tomorrow. I'm sensing cascading issues elsewhere in the motor and I'd like to just knock this one out so I can move on.