I put Rotella T 15w40 because I thought that was the proper thing to use but I now read in the owners manual that I should be using straight 40. I wish I read that first. I had 1 automotive mechanic tell me straight 40 and another marine mechanic tell me straight 40.
My boat has just over 4100 hours on the original 1986 Crusaders. Had a valve job somewhere around 2500 hours. The same yard has been maintaining the boat since 1990. They have been using Rotella 15w40 for a long time and when it gets warm in August the previous owner would pump out a quart and replace with Lucas Oil. I did the same thing in my last boat with the same motors. With that track record, I'm sticking with it.
My 1997 454 XLi's stated on the engine and in the manual to use straight 40 weight oil. I also had a phone conversation with a Crusader tech. He made it clear that SAE 40 was the proper engine oil. Bob
07-12-2018, 10:27 AM (This post was last modified: 07-12-2018, 10:38 AM by recppd.
Edit Reason: Add info
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I recently (June 2018) purchased a 2000 Tiara 3500 Open with twin Crusader 7.4L MPI engines. They run great, but I had no idea what was in them for oil since the owner always had a local marine mechanic do all his work. I called the mechanic today and he told me he used Mercruiser Synthetic 25w40 in the engines. Does this seem right? The manual calls for 15w40 and when I looked up the oil he stated it says its for an outboard engine. The boat is in Massachusetts so not super hot temps, and the boat will stay in during the water until probably late September to mid-October. Any thoughts?
I also forgot to add that my oil pressure during normal cruise is at 70 psi. That seems high to me and I'm wondering if its because of the higher weight oil in the engine?