1991 OMC 5.7l Oil recommendation

[[email protected]]

I bought this boat (26' FW Sundowner) in April. It had 281 hours when I bought it and I have put 45 hours on it since. I live right on Lake St. Clair so I boat on the weekends and a few weekdays as well.

The manual calls for straight 30w and advises against multi weight oil.

I'd really like to use a straight 30w or 40w synthetic, or a robust conventional is fine too.

Recommendations?

 

[Steve S]

I would pick any 15w-40 HDEO . That is what all the commercial marine placed use in their gasoline and high speed diesel engines in their boats. When I had a boat that is whati used if I got another boat that is what I would continue to use.

 

[[email protected]]

Thanks Steve.

I'd really like to adhere to OMC's recommendations and use a straight weight. I don't operate the boat in cold weather, so a multi-viscosity oil isnt needed and plus, Im nervous about shear.

Any straight weight recommendations?

 

[440Magnum]

OMC's recommendations were made in 1991, before the advent of the current crop of multi-grade synthetic HDEOs like RT5 and RT6. I personally would run RT6 5w40- its certainly better than any single grade oil made in 1991.

If you REALLY insist on single-grade,Delo 400 is still available in single grade and would constitute a "robust" conventional oil. Available at West Marine (and probably for a lot less elsewhere)
http://www.westmarine.com/1/1/29809-delo-400-motor-oil-sae-30-1-quart.html
Personally I'd consider it a step backward from RT6, though.

Or you can spend for Redline SAE 30 single-grade, but once again I think a multi grade designed for HD applications is better than a single grade tailored more for racing applications. JMO.

 

[Chris142]

Originally Posted By: [email protected]
, Im nervous about shear.

Your 350 Chevy wont shear a 15w40.

 

[gwdriver]

I agree with Steve and Magnum. The best thing for that engine is a 15W-40 HDEO. Forget the single weight theory.

 

[Steve S]

Originally Posted By: Chris142
Originally Posted By: [email protected]
, Im nervous about shear.

Your 350 Chevy wont shear a 15w40.
I didn't want to say anything. I have seen dino HDEO run in engines that I am sure cost more than my house (at the real estate peak prices!!!)

 

[gotnogunk]

Rotella makes a straight 30 weight

 

[440Magnum]

Originally Posted By: Chris142
Originally Posted By: [email protected]
, Im nervous about shear.

Your 350 Chevy wont shear a 15w40.


Or a synthetic 5w40.

 

[meep]

my 5.7 did quite well on rotella 15-40. 22' cuddy.

I stuck with that over 5-40 syn just because at 75 hrs per season--- syn seemed overkill. pressures were always healthy. Would have been interesting to see if syn gained some level of fuel economy, but in marine apps I doubt it'd register.

plus- it was either on or off.... so when it ran, it ran until destination, so it could heat up and cook off whatever it needed to cook.

M

 

[[email protected]]

Guys - thanks for all of the advice and tips!!

I actually listened and went with Delo 400LE 15w-40. It was on sale at O'Reillys for $9.99/gal. Cant go wrong with that

When I checked the oil on the dipstick - it looked ok. When I started evacuating it, it was BLACK as tar. No wonder I had a ticking lifter!

1 more question: How is Delo compared to Rotella or any other HDEO, in regards to TBN, etc?

 

[Bror Jace]

Good deal Chriznat.

"When I checked the oil on the dipstick - it looked OK. When I started evacuating it, it was BLACK as tar."

Sounds like some rocket scientist might've used a non-detergent oil in the engine for some portion of its life. Yes, no wonder you had a ticking lifter.

Don't be surprised if that HDEO turns dark rather quickly as it cleans out a lot of the old sludge you just know is in there.

Some of us here have our favorites among the HDEOs. I don't think anyone is going to be able to intelligently answer your question as the formulations change faster than people around here get UOAs. I tend to like Chevron, Pennzoil and Shell based on their reputations for frequently updating their formulas and their corporate reputations for quality lubricants in general.

 

[[email protected]]

I went back today and bought another gallon of Delo 15w/40 - its still on sale at O'Reillys for $9.99. Also picked up a WIX oil filter.

I bought 2 gallons last time but only used 6 quarts (out of 8), so with the other gallon I bought and the oil filter - Im ready for the end of season (gasp) oil change. Cant beat that price, Im sorry!

 

[Bror Jace]

Walmart has Delo 15W-40 LE for $8.50 per gallon around here.

You don't have to apologize to anyone here for amassing an oil 'stash.'

 

[[email protected]]

Originally Posted By: Bror Jace
Walmart has Delo 15W-40 LE for $8.50 per gallon around here.

You don't have to apologize to anyone here for amassing an oil 'stash.'

Bummer for me! Our local WM is $10.50 for a gallon of Delo LE 15w/40. O'Reillys regular price is $13.99.