Best type and weight of oil to use?

[Chuck Rowe]

1992 Horzion 190 with a 5.0L/Cobra King out drive. What type and weight oil engine oil should I use? Synthetic or not?<br /><br />Thank you.. This sight has been very helpful.<br />Chuck

 

[Boomyal]

Re: Best type and weight of oil to use?

Synthetic would be my choice. 15w-40 wt. Otherwise any good quality petroleum oil will do. Manufacturers usually recommend a single weight oil for marine engines. Usually 30 wt. If you want to make your head spin, do a search in this section for "oil".

 

[crazy charlie]

Re: Best type and weight of oil to use?

I like to stick with the manufacturers recommended oil and Merc recommends straight sae30 for most and sae40 for warmer climates or water temp.Many here like synthetics but you have to be careful because if you have even the slightest oil leak and you switch to synthetic there is a good chance the leak will worsen.Charlie

 

[LubeDude]

Re: Best type and weight of oil to use?

Originally posted by crazy charlie:<br /> if you have even the slightest oil leak and you switch to synthetic there is a good chance the leak will worsen.Charlie

Only slightly!<br /><br />You would have no problem with a 10W-30 or 15W-40, The diesel oils work very well, 15W-40 Chevron Dello 400 would be my choice for a regular oil, Amsoil 15W-40 Diesel Marine would be by choice for a synthetic.<br /><br />Use any filter but a Fram.

 

[cobra 3.0]

Re: Best type and weight of oil to use?

What's with Fram?

 

[summit1]

Re: Best type and weight of oil to use?

Will using a milti-weight oil cause foaming? Does the 15w-40 provide better protection than SAE 40 (I am in warmer climate)?

 

[Ralph 123]

Re: Best type and weight of oil to use?

There is just a ton of discussions here on oil and links to all kinds of great research on the subject. The main point I took away from all the reading is that straight oils (like 30wt) don't have the added viscosity-changing additives (chemicals) that can burn/breakdown under the heavy load a marine engine is subject to. In addition, if you use a multi-grade, get the one with the lowest spread because they have less additives e.g., 25W-40 is "better" than 15W-40 since the viscosity spread is less.<br /><br />Merc oil sold at most marinas is 25W-40. Heavy Duty Oil (Diesel) is 15W-40. I use straight 30 or Shell Rotella-T 15W-40 in my Merc 260s (Chevy 350). I have a Diesel pickup so I usually have plent of the heavy duty oil on hand.

 

[Wart T]

Re: Best type and weight of oil to use?

Using multi weight oil does not cause foaming.<br />40W is supposedly more stable than 15W-40. Quite frankly if you follow the engine manufacturers service recommendations you'll be fine with any good quality oil.

 

[MFG197]

Re: Best type and weight of oil to use?