can I put diesel oil in my engine ?

HPLou

Petty Officer 2nd Class
Joined
Sep 15, 2007
Messages
196
good day,

1980 Mercruiser MCM 898 (305) V8 s/n 5452697
I was told yesterday by a mecanic tech that I can put 15w40 diesel oil in my engine because it's old and diesel oil will better lubricate the engine. He recommended SHELL diesel oil.
Does it make any sense ?

Louis
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: can I put diesel oil in my engine ?

Ayuh,..... You can if you want too.....

Diesel oils are basically the same oils, with a higher detergent package.....

It comes down to my signature,.... Just change the word Grease to Oil......
 

ziggy

Admiral
Joined
Jun 30, 2004
Messages
7,473
Re: can I put diesel oil in my engine ?

theres been quite a few oil threads here on the fourm. use the search function to find a lot of info and opinions.... my opinion is i don't know which oil to use for being the best. however i feel that mercuriser probably knows what they think is best for mercruisers..... so, since i have a mercruiser, even though it is old like yours.... i use mercruiser oil... 25W-40.....
 

Mkos1980

Chief Petty Officer
Joined
Oct 25, 2007
Messages
640
Re: can I put diesel oil in my engine ?

I run Shell Rotella with no problems. I think it has a higher zinc? content which helps with the lifters vs todays newer roller lifters which dont need it
 

JustJason

Vice Admiral
Joined
Aug 27, 2007
Messages
5,319
Re: can I put diesel oil in my engine ?

if your in canada you may want something with a lower base stock. Maybe 10-30 or 10-40.
I have and old boat and i run straight 30HD. And i make sure i let it warm up every time before I take it out.

Nothing wrong with running an oil in the 40 and even 50 weights. as long as its not 0 degrees when you start it, and as long as you make sure it warms up first.
 

Robj

Lieutenant
Joined
Mar 22, 2007
Messages
1,441
Re: can I put diesel oil in my engine ?

Diesel oil is rated for both C and S engines, which means it is suitable for compression and spark ignition engines (gas and diesel). It basically comes down to the correct viscosity. 15W40 sounds good. Try it and see how it works.

Have a great day,

Rob.
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: can I put diesel oil in my engine ?

No problem, I use it in my 350..
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: can I put diesel oil in my engine ?

Hey!!! another oil thread!!!! We never have those......



Yeah you can use it (I use Shell Rotella 15W40 in mine)


(Although C & S have never meant compression and spark....it's a rough equivalence )



Just change it once a year...preferably right after your last run of the season.......your engine will never know the difference!





Diesel oil is rated for both C and S engines, which means it is suitable for compression and spark ignition engines (gas and diesel). It basically comes down to the correct viscosity. 15W40 sounds good. Try it and see how it works.

Have a great day,

Rob.
 

tommays

Admiral
Joined
Jul 4, 2004
Messages
6,768
Re: can I put diesel oil in my engine ?

WELL :D

Auto oils have had the ZDDP level reduced to meet current EPA requirments


"Most" :D true diesel oils should still there full dose of ZDDP (which is a good thing );)


Flat tappet cams like the ZDDP


Tommays
 

HPLou

Petty Officer 2nd Class
Joined
Sep 15, 2007
Messages
196
Re: can I put diesel oil in my engine ?

thanks for your replies and help.
I change engine oil one a year, I will try the Shell Rotella 15w40 this time.
I appreciate.
Louis
 

QC

Supreme Mariner
Joined
Mar 22, 2005
Messages
22,783
Re: can I put diesel oil in my engine ?

Here's the straight skinny on API Oil ratings. I was taught Compression and Spark as well, but it is Service and Commercial . . . I was also taught that when two ratings are given, such as CJ-4/SM, then the first one was the intended rating and the second was met based on the composition kinda by accident. Anyway, the chart explains it all . . .
 

Robj

Lieutenant
Joined
Mar 22, 2007
Messages
1,441
Re: can I put diesel oil in my engine ?

If I would have put commercial and service, most people would not know what I am talking about.........including myself. Spark and Compression is how I remember the difference.

Have a great day,

Rob.
 

HT32BSX115

Supreme Mariner
Joined
Dec 8, 2005
Messages
10,083
Re: can I put diesel oil in my engine ?

Oh...gawd! This thread ought'a be good for at least 100 posts!!!:p;)


Yes ZDDP (and diesel oils) is good for flat tappet engines....I'm also using it in my old Ford Y-block!

Unfortunately ZDDP coming out of all the oils, even the diesel oils, since it interferes with the cat converters and the after treatment systems in the newest diesels.

I haven't had a close look at the latest NMMA FC-W oil make up but I would be willing to bet that it will be the last oil to have a suitable level of ZDDP until marine (4-stroke) engines are forced to use cat converters (2 years maybe?)

Most new marine engines are probably not going to have problems since most are "roller-follower" engines anyway...

We'll all probably have to switch to Aeroshell 15W50 to continue to get the high levels of zddp or start using some snake oil additive sold at high price over the counter! (illegal in California of course!!)

The EPA is really beginning pizz me off!!!:mad:








WELL :D

Auto oils have had the ZDDP level reduced to meet current EPA requirments


"Most" :D true diesel oils should still there full dose of ZDDP (which is a good thing );)


Flat tappet cams like the ZDDP


Tommays
 

96lt4c4

Petty Officer 2nd Class
Joined
Jan 8, 2008
Messages
110
Re: can I put diesel oil in my engine ?

If you have a roller cam then you can run whatever you want. I was running Shell Rotella with the factory flat tappet. Now I am going to 5w 30 since I have installed the LT4 roller cam.

I have been hearing rumors that the ZDDP additive is on its way out of the Shell oil as well. My dad keeps tabs on it because of his Cuda.

Comp cams makes a cam break in additive that you can run with regular oil that has lower levels of ZDDP.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Re: can I put diesel oil in my engine ?

I use Fuchs 'Titan ultralube 15W40', because I have a petrol sterndrive and a diesel Landcruiser and want to use one oil for everything. Did a lot of reading before I made any decisions and concluded that the diesel oil was designed for high and continuous loads and was less likely to breakdown as quick as the oil designed solely for petrols.

Try this website, it has all you need to know....

'http://motorcycleinfo.calsci.com/Oils1.html

Chris..........
 

starsnstripers

Lieutenant
Joined
Nov 30, 2007
Messages
1,330
Re: can I put diesel oil in my engine ?

Well there! haha! I was wondering do they have a straight 30w diesel oil? I have an old motor too and i like the regular straight 30 but being their removing the zinc, if they have a diesel straight 30 is what i may try?
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: can I put diesel oil in my engine ?

Well there! haha! I was wondering do they have a straight 30w diesel oil? I have an old motor too and i like the regular straight 30 but being their removing the zinc, if they have a diesel straight 30 is what i may try?

Look for Rotella in straight 40wt..its out there..
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: can I put diesel oil in my engine ?

I have been hearing rumors that the ZDDP additive is on its way out of the Shell oil as well. .

Its on the way out of everything soon (the "cat" thing). BUT, you CAN buy it as an additive in 6oz bottles or something like that. Looked into it last year, after reading a good article in Hot Rod..I'll see if I can find more on it..
 

Scaaty

Vice Admiral
Joined
May 31, 2004
Messages
5,180
Re: can I put diesel oil in my engine ?

Google ZDDPlus.com
Also Summit Racing sells a Bottle of Cam Break-in stuff, Made by Crane...
"Crane Super lube Break-in Concentrate"
Just use it every oil change..
GM used to sell good stuff, but the EPA nailed them on it too
 
Top