Be careful on your multi-grade oil

K

knotflying

Well-known member
Joined
Jul 25, 2010
Messages
6,014
Fluid Motion Model
C-28
Hull Identification Number
FMLT2731J011
Non-Fluid Motion Model
25' Parker & 246 Robalo Cayman
Vessel Name
http://illusionsmikeandjess.blogspot.com
According to the Yanmar manual on the 4BY2 engine you have to use an approved full synthetic oil with a multi-viscosity range that can go as high as 0W-40. Since we are in Rhode Island and now in Florida I have been using the 0W-40. After just 15 hours on my new oil in Florida with temperatures around 80 degress during the day, the low oil pressure alarm would sound at idle. Yanmar sent a mechanic out to us in Ft. Myers Beach and they replaced the oil pressure sending unit, NO JOY. After speaking with the mechanic about the last oil change and what I used, he suggested that we change the oil to 5W-40 and called Yanmar to confirm. Well as of this writing it worked! Firstly, anyone out there considering 0W-40, don’t ! Secondly, Yanmar needs to put some clarifications in their manual. Thirdly, I am hoping they will come up to the plate and reimburse me for this!
Now, onward with our trip,
ILLUSIONS
Mike & Jess Rizzo
 
That's interesting. In theory, that should have made no difference. The first number is the cold-temperature viscosity and should only effect starting, and primarily when the temperatures are low, not at hot idle. The second number is the operating-temperature number and 40, is 40, is 40. Multi-viscosity oils are exactly that. They change viscosity as the temperature of the oil changes. An oil rated as a 40 should have the same viscosity as any other at the oil-industry standard temperatures regardless of the cold-temperature rating. Obviously the change made a difference for you, but you should keep an eye on things.

I don't know who did the first oil change, but are you certain they got all of the old oil out? It is hard to tell on diesels by looking at the dip stick since after about half an hour of running, the oil is about as black as what you just pulled out. Also are you certain they used a reliable brand of diesel oil, and that it met the Yanmar spec?

Obviously if you did the changes yourself, that should not be a problem. In that case, I would keep a close eye for the situation to repeat. Does your engine run hot when idling? Even a clogged strainer or damaged impeller can cause that. I assume you have instrumentation with gauges, not just lamps and buzzers as I do on my R21.

It is also possible, but not too likely, that the relief valve which sets the oil pressure in most engines may be on the low side of its specified setting.

There are all sorts of other potential causes on these wonder-engines of today, including the initial fix which seems to have been a red-herring in this case. But changing the cold-temperature viscosity rating making a difference definitely surprises me.
 
Your points are all what I brought up with the Yanmar mechanic. I did all of the oil changes myself and I am very meticullous. I made sure that what I took out was just about all the oil. I did an initial change at 35 hours on the engine and used 0W-40 and used it all summer in RI, no problem. At 80 hours same procedure, but did not use the boat until Florida. In theory you are supposed to go 250 hours between changes. I used Mobil-1 an allowable oil as shown in the manual. I agree with everything you said, the oil should get thicker as it gets hotter. My engine runs at 197 degrees. When I started the engine cold I was getting good pressure, as it heated up it dropped to 2lbs at idle. The dip stick showed I had the proper amount of oil. So go figure. I will definitely keep an eye on this, but as soon as the new oil went in all symptoms disapperared. I let the engine run up to 183 degrees and I was pumping 14 to 16 lbs at idle, go figure. I'm still scratching my head as to why this would happen as the oil heated up, but the mechanic insisted that was the problem and so far he was correct.
 
Knotflying,
I'm surprised that your engine is running under 200 degrees. At 3,500 rpms, mine is indicating 205 degrees which seems to be the norm from what I've read.
Phil
 
Mike, I run around 204-207 in my 150 hp Yanmar which is about where others are on the spectrum from lots of posts on Tugnuts regarding the new Yanmar engines. It's nice to be on the colder side and, as I recall, around 197 is where the manual says you should be.
 
Yes, at least the manual was correct on the temperature range. As of this writing I have good oil pressure. I sent all of my information (including the bill from the mechanic) over to our good friends at Ranger to have a discussion with Yanmar about this issue. Besides the cost associated with this, they really need to change the wording in the manual so others don't have this problem.
 
knotflying,

On my R27, when the oil was changed at 50 hours, the marina used Shell Rotella T6 full synthetic 5W-40 as recommended to them directly by Yanmar. My temperature never exceeds 198 degrees.
 
Go figure, the manual does not list Shell Rotell as an acceptable oil brand. I would have Yanmar confirm (in writing?) that they allowed it. In any event it also needs to meet the service categories as well. Someone at Yanmar needs to ensure that they are all on the same page, which happens to be several in this case specifiaclly pages 25,26 27 and 28.
 
I used Penzoil Ultra Euro 5-W40, listed as an approved oil, and got a free Ferrari cap with the oil. Apparently it is the only oil recommended by Ferrari. I've noticed that my boat accelerates and corners better since the 50 hour oil change.

Phil
 
Let me know how you do on the Autoban. Free hat? I paid $9.00 a quart at the BMW place and all that I got was a receipt.
 
knotflying":ws46ypjr said:
Let me know how you do on the Autoban. Free hat? I paid $9.00 a quart at the BMW place and all that I got was a receipt.
Click to expand...
At least we do not need many quarts.
 
FYI< we are on our 3rd oil pressure sending unit with only 450 hours on our engine.... "apparently" Yanmar has had a "problem" with these but have been somewhat quiet about it.
For what it's worth....

Tim & Kim
R29-Hermitage
Gibsons, B.C.
 
The saga does continue.....My low oil pressure alarm is sounding off again. Perhaps the first diagnosos was wrong? Well I made it to Marathon and will be seeing the local Yanmar Mechanic recommended by the local Yanmar distributor. Stay tuned.
 
Update at Marathon, FL, A mechanical gauge was connected and the pressures at idle and full throttle are where they should be, good news. A new sending unit was installed (third one) and the orifice was drilled out a bit larger, no joy! The electrical gauge is reading between 12 to 15 lbs. lower than the mechanical, hence in neutral zero pressure and annoying bells and whistles! So now we wait for Yanmar to get back to the mechanic to tell him what to do. Hopefully, the answer isn’t to get sound deadening earphones!
 
Thanks for posting this information Mike. Yanmar has indeed seen their fair share of issues on these oil sending units on the newer style BY engines. I have recently sent an email off to yanmar about this issue. The good thing is, it is not a critical part of the engine but rather an annoyance that the alarm can create if the pressure shows below or above yanmar's allowed pressure.

I am a firm believer that the oil viscosity was never the issue but we will leave it to the experts. I am sure that Mike will report his findings once Yanmar gets this problem resolved. Thanks again for keeping everyone in the loop and sorry for the troubles you are going through on your vacation. Let me know what I can do to help.
 
UPDATE: Problem Fixed and keeping fingers crossed. The wire going to the wiring harness at the pin had a bad connection. Once that was discovered and fixed, oil pressure at idle is running at 24psi, at full throttle we are getting 72psi. The numbers are holding consistent as well and not varying as they were before. Yanmar and their field service people have been very attentive in this situation as has Andrew, Kenny and Peter Haywood from Winter Island Yachts. The mechanic in Ft. Myers was a bit off with their diagnosis and I am told I will be reimbursed for that. The mechanic in Marathon (Louis Garcia, Marathon Diesel Repair 305-743-7116) is what I would call a meticulous, proffessional who does not believe in throwing parts at things but methodically worked the issue. Anyone with problems with their engine in the Marathon area should go there.
That's All Folks!
 
Update: Kudos to the cast of characters for stepping up to the plate. I received a check today from Mastry Engine Center in Florida for reimbursement of my oil change due to a field mechanic’s misdiagnosis related to my low oil pressure. Ranger, Yanmar and Mastry were true to their word.
 
Great...
 
And the saga ends on a happy note. That's good news after all you were through Mike.
John
 
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