Oil Consumption 2013 SAN 230 W/ PCM ZR409

[shrutefarms12]

I have been a long time lurker on this forum but this is my first time posting so hopefully I have this in the right place. I have searched all over this forum and the internet trying to find someone who is experiencing similar issue to me. We have a 2013 PCM ZR409 in our SAN 230 and it currently has 780 hours on it. The engine runs great but lately it has been consuming a bit of oil. I would say a quart every 20-25 hours or so. It also varies with RPM and load. We have always changed the oil every 50 hours using Mobil1 5w-30 synthetic. I also did a full coolant drain and refill last season. Boat always holds proper temp. I changed spark plugs at the end of last season and nothing was out of the ordinary. I am not leaking oil anywhere and the boat isn't throwing any blue smoke and really any smoke at all (we don't have surf pipe) when running.

I have read on auto forums that a lot of the 6.0's came with a poorly designed LH valve cover which houses the PCV port. Changing the valve cover to the updated design seems to have solved a lot of the oil consumption issues. Should I pull the valve cover to verify if it is the updated design? Or should I do some diagnostic testing first (compression test, leak-down, etc.)? I have been hesitant to pull the cover because I would have to remove the exhaust manifold on that side. I pulled the PCV hose that connects the valve cover to the intake manifold last season and it was quite oily. I cleaned it the best I could and reinstalled but just looking for some direction here from someone who knows these engines well or has experienced similar symptoms.

[jpwhit]

I've worked on that engine before, but I don't have first hand experience where I owned a boat with that engine to be familiar with it's oil consumption. But here are a couple of thoughts.

Is the current oil recommendation from PCM 5w-30 or 15w-40. They have changed some of the oil recommendations so make sure you're checking the latest info. May even want to try calling them to discuss what you're seeing. Thicker oil will tend to resist getting sucked up into the PCV valve more than a thinner oil.

Half descent borescopes aren't that expensive on amazon, I wonder if you can use one to see inside the valve cover w/o having to take it off. But I'd try pursue the oil viscosity and seeing if you can talk to someone at PCM first.

[NautiqueJeff]

That's the right oil. Here are the latest requirements:

PCM Oil Advisory

[shrutefarms12]

jpwhit Thanks for your reply! Pre-2019 they always recommended 15W-40. We had a 2007 Air Nautique 226 with the ZR6- same 6.0 block - before this one and always used 15W-40 and never had an oil consumption issue. That motor had 750 hours on it when we sold it. But in 2019 PCM issued a bulletin stating everyone should switch to synthetic 5w-30 so when we got this boat I always used synthetic 5w-30. Boroscope is an interesting idea that I will look into... and I will reach out to PCM and see if I can get a response from them.