No Oil Pressure. No Problem?

[Thin_Water]

First time posting on the forum, and in need of help. I am in the final stages of buying a used 2017 Lagoon 42. The boat is located in Grenada. I visited the boat last week for the survey and sea trial. The boat was in great shape and as described by the broker. The boat was on the hard when I arrived (and had been for hurricane season). Getting the boat launched, rigged, sailed, and re-hauled was exhausting.

Once we launched the boat, the broker started both engines without issue. We checked transmission operation, cooling water">engine cooling water flow, and the bilges for leaks and all was fine. We motored out, put up our sails and enjoyed surprisingly nice performance from the Lagoons’ sail plan. At the end of the sail, I was at the helm and restarted the engines; again without issue. During the motor in I scrolled through the LCD screen at the bottom of the tachometer. I can’t remember all the available data, but I do remember that both engine temperatures were fine, but when scrolling through the oil pressure the display just displayed dashes. Something like this ---. I shut the engines down one at a time with the kill switch (power still on) and didn’t hear a low oil pressure alarm. Every boat I have ever sailed/owned has had an audible low oil pressure alarm that is tested at start up and shut down.

After the visit, I made the buyer agreement for the boat conditional on a few items. Having a Yanmar mechanic fix the audible alarm, straighten out the LCD Oil pressure display issue and confirm that there was no actual oil pressure problem, and confirm all issues were related to either a display/sender problem.

The seller agreed to my terms, but now the broker for the boat has come back with the following: “As per our telephone conversation yesterday here is what I have understood from the Yanmar representative. The new common rail engines so the 4JH 57 that we have actually on (the boat) have no more buzzers like the old systems. With the new generation of engines. It is not obligatory have oil pressure senders, it is an option as the engine won’t start if there’s an oil pressure problem and will mention error on the reading panel. Having senders installed on the engines is an option that lagoon factory did not take as they considered that having an engine that won’t start with oil pressure and an error reading on the panel is enough.”

The engines were running for at least 30 minutes. During that time the engine temps were rock steady.

Can anyone confirm what the broker is saying? The Yanmar manual I found online makes no mention of an optional oil pressure sender. Thanks for your help.

[gmakhs]

I see how the pressure on the screen can be optional , but there should be an alarm like on every engine .
It's better to get a mechanic to check it ,probably the issue is with the oil pressure sensor or the cabling to the alarm, if.the alarm haven't been put from.the factory (really weird ) ask the mechanic to add one.

If the engine have enouph oil I don't believe there is any real issue with the engines but a mechanic will be able.to determine that .

I wouldn't let the broker to choose the mechanic .

[kmacdonald]

The engine doesn't have oil pressure until it's started so saying it won't start without oil pressure is wrong.

Judging from the brokers response, I would guess there is a problem and the alarm and pressure senders were disconnected.

[Thin_Water]

Thanks Gmakhs. Because the engine has an ECU I can’t image that it would let the engine run without oil pressure, but if the ECU knows the oil pressure, why won’t the LCD display it since it already displays the engine water temperature.

I am hoping a Lagoon 42 owner can shed some light on this issue.

Thanks for the suggestion on the mechanic.

[Thin_Water]

Hi kmacdonald, My first thought is that there is something to hide as well, but I wanted to see if perhaps I am being paranoid.

[Wotname]

Yep, get another opinion. I might believe there isn't an audible alarm if there was some automatic engine shutdown circuit when oil pressure drops but I would never believe It is not obligatory have oil pressure senders, it is an option as the engine won’t start if there’s an oil pressure problem and will mention error on the reading panel.

How can the ECU know anything about the oil pressure if there isn't a pressure sender of some sort.

Clearly something is wrong somewhere!

[Wotname]

Originally Posted by Thin_Water

Hi kmacdonald, My first thought is that there is something to hide as well, but I wanted to see if perhaps I am being paranoid.

The best time to get paranoid is right now, i.e. before completing the purchase!

Now is the time to flush out anything that might be getting hidden. If nothing is wrong, it will soon become apparent but if you aren't looking, it will remain hidden until you are the new owner.

BTW, good to see your first post of CF

[kmacdonald]

I think you caught the broker in a lie. Drop you offer $60k for a new set of engines.

[Compass790]

I would screw a mechanical gauge in where the sender is & check as others suggest. Make sure you view it yourself & make sure the engine is fully warmed up as the oil pressure drops when it's hot
It may well only be a sensor problem but it would be mad to take the brokers word for it.

[Compass790]

I'm curious as to how the CPU knows it has oil pressure before it has started as unless it has an electric priming pump it wont produce oil pressure until it is started or at least turning over. Does it shut off a fuel solenoid in a few seconds. Sounds very fishy but I don't know the engine

[RonRicco]

So for what it is worth with my 3ym30s, there is only an alarm and no actual oil pressure readings. The instrument panel(s) are not original and they allow you to scroll through the voltage, oil pressure etc, but the panel also only gives the dashes as well when on the page with the oil pressure reading, but the alarm will sound (with light) with low pressure.

Because you don’t have a reading and only an “idiot light” doesn’t mean that your actual pressure is low because you have the dashes.

[kmacdonald]

Yes, an oil pressure switch is usually standard and a oil pressure gauge with sender is optional. Sometimes the oil pressure switch and sender is a single unit with two wires.

[DeepFrz]

Contact Yanmar. Everyone else is guessing.

[Thin_Water]

Originally Posted by DeepFrz

Contact Yanmar. Everyone else is guessing.

I appreciate all the input. It is a strange situation. I was hopeful someone with a Lagoon 42 would just reply that this is absolutely normal.

I am obviously well into the process and have spent considerable money flying to Grenada and surveying the vessel, so am in a buy mode, but now need to be more objective than ever.

I don’t have a good resource for a Yanmar mechanic. But that is on my list to find. This website and noosite are two of the best websites I know.

[DeepFrz]

The engine operation manual shows oil pressure guage (electronic display) and what you should expect after starting; ie. oil pressure, engine temp, and rpm. Again, I don't know if the prospective boat's engines are using the same setup but Yanmar shows that they do display the oil pressure. Somewhere around page 24 and then around page 55.