High oil pressure in my Westerbeke 44C

[RickMorgan]

My 44C shows OP in the range of 75-80, consistently. Its only 4 years old, run moderately. Oil changed 6 weeks ago, new filter. Have checked the wiring from the sender to the gauge and replaced the sending unit, to no avail. No signs of oil leaks or burning (oil in combustion chamber).

Is high pressure doing any harm? Next step is changing the gauge (18yo, original to boat), but we are cruising new england at the moment.

I just had to replace the oil pressure switch, and now my low oil pressure alarm sounds constantly! I hate to disconnect the alarm, but i cant isolate/fix the problem.

Bad wiring, bad gauge, or bad karma? Help, as this is going to kill our sailing season!

[a64pilot]

First what is acceptable for that engine?
It may be within limits, my 30yr old Yanmar runs just under 60.
Then before you do anything else, put a mechanical gauge on it and verify that pressure really exists.
About the only thing that can cause high oil pressure is a stuck oil pressure relief valve, usually, but not always located as part of the oil pump.
However in 30 years of being a professional mechanic I have seen exactly zero stuck closed high pressure relief valves, so I’d say it’s unlikely.
However I’d prioritize fixing my low oil pressure warning alarm.

Does You low oil pressure alarm not sound, then begins to sound once the engine is started? If so then you likely have the wrong switch, you may have a normally open switch, when you want a normally closed, other wise try to disconnect the switch and see if alarm still sounds, if it does, then you have a short somewhere, if not then that points to the incorrect switch, again.

[a64pilot]

Just remembered, pressure gauges are matched to the sending units, by that I mean there are different types, putting the wrong type in will guarantee incorrect readings.
You sure you put in the correct sending unit? Did this high pressure exist before you changed sending units?

[model 10]

Oil pressure relief valves don't stick closed and there is no way that over time your engine could gain more oil pressure unless the filter is clogged or the meter is bad.

Sometimes you need to flush the oil passages for the oil switches as they get clogged with mung. A new low psi switch can clog in no time. There is a trick from aviation, fill the port/line and meter with a different oil that is not all thick and funky. We used hyd oil. It would still be in the meter years later.

[keepondancin]

Try to get a pressure gauge and screw it in where the sending unit is, to verify pressure. I had the opposite on my 63c, suddenly low oil pressure. Spoke to a mechanic, listed all the potentials, and said start with the cheapest easiest ones first. Changed the filter with only two hours of use, and oil pressure is fine. Spoke to NAPA dealer, he said usually it is high pressure with a defective filter. Change the filter and give it a try.

[RickMorgan]

According to the manufacturer, Normal range is 50-60psi, my other engine runs in that range. I’ll take a shot at a new oil filter.

The new high range happened suddenly, with the change of sender and op switch, both OEM parts.

Thanks for the suggestions!

[Wotname]

Originally Posted by RickMorgan

According to the manufacturer, Normal range is 50-60psi, my other engine runs in that range. I’ll take a shot at a new oil filter.

The new high range happened suddenly, with the change of sender and op switch, both OEM parts.

Thanks for the suggestions!

Very good chance your OEM sender does not match the 18 year old OP gauge.
Can you be sure this sender is the correct one for the gauge?

Refer to A64's post #3.

[a64pilot]

Originally Posted by RickMorgan

The new high range happened suddenly, with the change of sender and op switch, both OEM

Try a filter, easy to do, but I bet lunch that isn’t it.
Seeing as how the problem appeared with the new sending unit, I’m betting that is it.
Why did you change the oil PSI sending unit?

High oil pressure is possible, just I have never seen it, even a clogged oil filter should not cause high oil pressure, because the pressure relief valve controls pressure.
I can’t think of anything it would harm except maybe the oil filter either, no seal that I can think of actually has oil pressure against it, except the oil filter.

[ZULU40]

Originally Posted by RickMorgan

I just had to replace the oil pressure switch, and .....

the sender isnt compatible

[Mojadito]

The sender for the gauge is, more than likely, the one that is used to drive 2 gauges in a dual panel arrangement. When ordering the new sender, be sure to specify that it is for a single gauge,.

[RickMorgan]

Tried the oil filter change this am, no change in pressure. I have an anolog pressure gauge, thought to fit it where the sender goes, to get a realistic oil pressure. Unfortunately, it is 3/8” thread, and the fitting is 1/4”. A trip to the hardware store should fix that.

I’m inclined now to think that it is either the gauge or the sender wire. Ran the motor for 3 hours today at cruising speed (2000rpm), OP held steady at 80psi. No sign of oil being forced into combustion chambers, or out seals, no drips of any kind, no oil burning smell or oily exhaust. So what am I missing?

Ordered from Westerbeke through reliable dealer, according to the part number in my manual. No mention of alternate part #for a two gauge helm.

Calling Westerbeke support tomorrow to answer compatibility questions and more.

Thanks for all the advice!

[Exile]

Originally Posted by RickMorgan

Tried the oil filter change this am, no change in pressure. I have an anolog pressure gauge, thought to fit it where the sender goes, to get a realistic oil pressure. Unfortunately, it is 3/8” thread, and the fitting is 1/4”. A trip to the hardware store should fix that.

I’m inclined now to think that it is either the gauge or the sender wire. Ran the motor for 3 hours today at cruising speed (2000rpm), OP held steady at 80psi. No sign of oil being forced into combustion chambers, or out seals, no drips of any kind, no oil burning smell or oily exhaust. So what am I missing?

Ordered from Westerbeke through reliable dealer, according to the part number in my manual. No mention of alternate part #for a two gauge helm.

Calling Westerbeke support tomorrow to answer compatibility questions and more.

Thanks for all the advice!

Let us know, if you can, how you contacted WB support and how it went. It's been awhile so maybe they've improved, but my experiences from a few years ago were miserable.

I've had to replace at least one sender on my WB 82B and was told at the time that they are somewhat prone to failure. My psi gauge on my WB generator has always read what I think is probably high (70-75 psi) but troubleshooting it never got me anywhere so I've just lived with it. Never took the obvious step of testing with a mechanical gauge but should do that one of these days.

[a64pilot]

Take a look at an engine oil pressure diagram. Oil pressure doesn’t exist at any seal, nor the combustion chamber etc. the main and rod bearings float on a film of pressurized oil, as does the cam, oil is pumped to the head and lubricates the valve train up there and drains back by gravity, and sometimes is sprayed on the bottom of the pistons to help cool them, but that is about it.
That is why you can take the oil filler cap off when an engine is running and oil not get everywhere, it may splash out, but except for blowby, there is no pressure inside an engine, except for its oil galleys.

Now some engines run very high oil pressure and often live very long lives I believe due to it, My Duramax would run up to 90 PSI if I remember correctly and may blow up a cheap oil filter, or so I heard. I never ran cheap filters.

[model 10]

Some engines have a pressure oil passage in the head gasket for the valves. Perkins for one. If it were to leak it would be out of the engine not into the engine.

[ZULU40]

Originally Posted by RickMorgan

Ordered from Westerbeke through reliable dealer, according to the part number in my manual. No mention of alternate part #for a two gauge helm.

Calling Westerbeke support tomorrow to answer compatibility questions and more

I recall a former employee from Pearson telling someone on a forum they had as many as 4 different suppliers for the instrument sets with their Westerbeke W40 supplied alternator kits so they need to know what you have.



EDIT: this matters because the tachometers for respective alternators differed slightly



It could also be that there was a replacement sender or gauge from a previous owner.