Which oil is Best?

[Grumman]

Hello all you diesel loving fans, I have a question on motor oil. I have been using the Rotella (shell) 15-40w for my 6.5. Friends have been telling me to switch to Mobile one. Does anyone have any opinions or facts?

Thanks,
David

[ANXIOUS-SUBMAN]

I see that you are new to the board (registered 6/18/05) I read this board almost every day and I can assure you that the answer to your question is in the archives somewhere if you take the time to do a search. It may take a couple beers to read through it all but it's there somewhere. If you still can't find your answer, I'm sure that one of the many knowledgable people on here can answer your question ;)

OBTW..I've been using the Rotella for all of the four plus years I've owned my sub. I have the oil bypass installed and I'm thinking about changing to Amsoil Syn on my next oil change.

[CareyWeber]

Originally posted by Grumman:
Hello all you diesel loving fans, I have a question on motor oil. I have been using the Rotella (shell) 15-40w for my 6.5. Friends have been telling me to switch to Mobile one. Does anyone have any opinions or facts?

Thanks,
David Mobil 1 has not been a good choice for the 6.2/6.5 engines because they require oil with a CG-4 rating. Mobil 1 did not have any oil rated higher than CF-4 until about a month or so ago when they brought out Mobil 1 5Wx40 (might be 0Wx40) it has CI-4 rating so it will work in the 6.2/6.5's.

Dr Lee wrote a great note about the reason for the CG-4 rated oil and the soot handling of it.

Carey

Edited for gramar redface.gif

[ 07-01-2005, 02:50 AM: Message edited by: CareyWeber ]

[sturgeon-phish]

Amsoil Diesel Marine. Gained almost 2 mpg. I loved the stuff so much I became a dealer just to get it!
Jim

[damork]

You will likely find opinions on oil vary as much as they do about what brand of truck to buy. There are 6.2 and 6.5 GM diesels that have made it to 500,000 miles with Rotella T, Chevron Delo 400, Mobil Delvac 1300 and others. Synthetic definitely has it's benefits. I use it in the winter to help cold cranking speeds and it has the biggest benefit in reducing piston scuffing and other wear when it is really cold (sub zero, etc).

I've run Delvac 1300 when I can find it or Rotella T, both work fine. I have started adding some Red STP to boost the antiwear additive. I've always had to add about 1 quart in 2000 miles, but it has always been consistent.

[Dvldog 8793]

Howdy
Damork pegged it right. Everyone has their own opinion. I run Mobil Delvac 1300 in the summer and Delvac 1 in the winter. Delvac 1 is true synthetic Mobil Diesel oil, it's been out for years and has always been certified for ALL diesels. The bad part about what it used to be VERY hard to find and was over $5/qrt :eek: Now that Mobil has the "truck & SUV" 5-40 at Walmart for 19.00 for 5qrt I might run that year around. I think the key is to change it often, unless you has a bypass filter system and extened capacity. No matter how good the oil is SOOT will wreck your engine! I have low opinion of Rotella, but that is just my OPINION, and EVERYBODY has one of those already! tongue.gif
Do a search on this subject. Also there is a oil test sight someplace that seems to be doing a good job. I think the link is posted here try a search under oil test.
L8r
Conley

[Hansh]

I use Amsoil 15W-40 Diesel/Marine synthetic. On the block I took out due to a cracked piston, approx. 115,000 miles, I could still see the hone marks. Is that normal or just good lubricant properties? New engine will also get Amsoil. I also use Amsoil gear lube in the diff, and trans, 5 speed.

[Dvldog 8793]

HH-
My block was the same, looked like new on the inside with NO lip and the cross-hatch looked fresh. Also no sludge beyond what was caused by the antifreeze. I owned the truck since 40,000 and always used Mobil 1300 oil. The previouse owner used whatever he could find that was CHEAP. BUT both of us change the oil at 3000-3200 ALWAYS. I've changed my oil at a roadside rest in the middle of the night!
I think it has allot more to do with changeing often than what type. That said I still and probably always will use Mobil.
L8r
Conley

[Hansh]

Interesting, with my dual bypass filter system I have changed my oil as early as 8,000 miles and as late as 24,000 miles, always sending in samples in between. My cracked block also did not have a ring ridge. I am not sure what the previous owner used for oil.

[eracers999]

It's interesting, if you read the question on the topic was (witch oil is best). Im not going there with a opinion, but i will say that my school of thought has always been you get what you pay for. I have always tried to buy the best stuff out there, dont care what it costs.

Kent