Remove the oil fill cap with the engine running at idle and hover the palm of your hand over the opening. On a new engine you should feel a little pulse but in a well used engine you can feel a thump. If you feel a thump and you do not operate the boat in freezing temperatures it will be OK to use 15W40. In cold weather the thicker oil may cause the starter to turn slower and may require some warming up of the engine to get the oil flowing before getting underway but it will be fine to protect the engine. In older worn out engines I have used an additive on top of 15W40 to thicken the viscosity even more, but I'm here in Florida where 90F temperatures will thin out the thickest of oil. On a 1984 engine where you may be loosing up to 1/2 a quart of oil to blow by in 20 hours I would definitely go to a thicker oil. Anything to delay an engine rebuild. Try Shell Rotella T4 15W40.
Oil loss through oil breather
- Thread starter ontherocks83
- Start date
None of the advice here has been wrong, the challenge is picking out what is correct for your motor. Your motor as described has all the classic symptoms of the "Grandma Car Syndrome" I've seen things as varied as water, Marvel Mystery Oil, Seafoam, or transmission fluid poured down the intake. This can be precarious as too much too quickly will get you hydrolocked and a bent rod. Pick out the oldest crustiest guy from a list of reliable diesel mechanics and see what he says. Don't trust the fate of your engine to a bunch of yahoos on the internet.
All that said were it mine I'd try the Mystery Oil letting it sit on top of the pistons and soaking into the rings over a couple of days to free them up. I am not familiar enough with your engine or your mechanical abilities to suggest a good method of doing that.
Keep us apprised of your progress.
All that said were it mine I'd try the Mystery Oil letting it sit on top of the pistons and soaking into the rings over a couple of days to free them up. I am not familiar enough with your engine or your mechanical abilities to suggest a good method of doing that.
Keep us apprised of your progress.
Except, some of us, who KNOW this engine, and actually HAVE ONE IN OUR BOATS, have suggested what the OP should do, first. He is simply MISSING THE HOSE that BELONGS on that fitting. THAT IS ALL, for now. I have the same engine he does, and have been running it for 23 years.
Last time I looked that is the entire purpose of these forums, to find folks who can give you the right answers. I didn't have this "luxury" back when I bought my boat in 1998!
Except some of the answers are from people with different engines, who have no clue about THIS particular engine. Look, Rick, I don't answer questions about Yanmar engines BECAUSE I DON'T HAVE ONE and hesitate to make analogies for equipment I do not have personal experience with. I think it's misleading for folks to do that, so I don't and hope the OP understands the differences.
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We have the Universal 5432 with 1100 hours and have used nothing but Rotella 15w-40 and never have had any engine problems.
I have a different engine, but these are common diesel issues. First of all if you think you have excessive blow-by try this test. Put a small hose on the breather vent and submerge it in a glass of water. Observe the bubbles (blow-by) while the engine is running. Should be a steady bubble rate and not a splashing out of the glass rate. Some blow-by is normal. Also, look at the rear of your engine at the bell housing. Inside there is your rear crankshaft oil seal. These can break down at the age of your engine and leak oil into the bell housing. Just a few thoughts. Don't rush to a ring job. Good luck