02 22i merc 350 Why so many different oil recs.

[DirtNasty]

I am trying to find out a good oil recommendation. I have searched and read alot of threads on oil and there are so many people using different oil. My manual says 20w50 and say synthetic not reccomended. That being said, guys are running amsoil, rotella,penzoil, 30wt,40wt,... and so on. So I just changed oil and filter and replaced oil with rotella. I have only used that in my diesels. I have seen several threads that say use it..... but im am skeptical and want to get some more info. I have about 700 hours on my boat and live in Texas. The boat is only used in the spring and summer so temps are HOT! most of the time. I run mobil1 in all my cars and trucks but is it safe to run in the boat engine? I'd just like a clear answer on a quality oil to run.

[chpthril]

Pick a brand name and im sure it will be a quality oil. weight wise, im partial to a multi-vis for the start up pumpability. I use a 15W40. I also prefer conventional oil over Syn. I do not see a benefit to outweigh the cost.

You'll never get a clear answer, but you will get lots of good ones.

[JohnnieMo]

Www.bobistheoilguy.com

I found that link on Tigé owners and I bought in to what he was saying. Short answer - run synthetic.

[boatwakes]

Yo dirt, simple answer is the oil produced today lacks many of the additives it should have to keep things from grinding. Mercruiser's oil is 25w-40 only, don't run 20-50 unless it's from Torco. I use Amsoil 10-40 marine and Mobil1 10-40 would be a great substitute (however, they're not a true synthetic but why argue over technicalities). Remember too, marine engines are under load 100% of the time when they're in gear, vehicles not so much, so the quality and temperature protection required for those load demands should be respected to ensure long bearing life. I've preached about Rotella 15w-40 on this site since I joined and it's fantastic oil. We use it in all our marine engine oil changes except where Caterpillar requires straight 30wt on their 3116, 3126 and C7 marine engines, aftercooler issues with multi-grade. Choose what you want but be educated when asked why, it does make a difference.

[IDBoating]

Three quick points:

1) Unless you run your boat engine literally every day, stick with traditional liquid dinosaur and don't use synthetic. Dom (here on Tige) has run tests showing that while synthetic has excellent lubrication properties, it tends to "drain off" of the metal surfaces such that they start "dry" if allowed to sit for a while. Traditional oil tends to "stick" to the surfaces better so the engine has better protection at startup.

2) No matter whose oil and what type you use, always change on the ENGINE manufacturer's schedule. Don't believe those claims by some expensive, typically synthetic oils about how you can go 25,000 miles between oil changes. That's for typical over-the-road engines which don't see the duty cycle that marine engines do. If the engine manual says every 50 hours, change it every 50 hours. Period.

3) After much research I chose Rotella T 15W-40 for my engine that recommends 15W-40. The "T" is important; there are several types of Rotella oil and the "T" is what you want for a marine application. Yes, it's labeled as a diesel oil but that has to do with the loading and duty cycle, and diesels often see a workload closer to that seen by our marine engines.

Just my $0.02. Hope it helps!

[DirtNasty]

I used the rotella t thanks guys.