Jump to content

What motor oil are you guys using?


Recommended Posts

I'm going to be replacing my oil pan gasket and rear main seal soon and I was hoping to be able to use synthetic oil when finished but with all that mixed info on newer oil and the lack of ZDDP being bad for flat tappets I was wondering if you guys ( especially the guys running synthetic) would share what brand you use. I'm currently running Kendall 15W-40 diesel oil mixed with a quart of Brad Penn high Zinc 15W-40. Thanks

Link to comment
Share on other sites

Rotella T 5w40 right now. In summer 10W40. If the new(to my MJ) motor didn't burn as much as it does (waaaaay more than the last motor) I'd be running the T5.

 

I ran 5w30 year-round in the old motor, and watched the oil pressure decrease until a severe bottom end knock developped. The two may not have been entirely related, but I don't care for it to happen again. Mind you, a $300 XJ is only six or so oil changes...

Link to comment
Share on other sites

Rotella is good, but I prefer Chevron Delo 400 LE 15w40. Year round. It meets the API classification SM for older engines, and still has a minimum 1300 ppm zinc count, unlike Rotella ~1100 ppm, and is the only off-the-shelf motor oil I know of one of the few motor oils that still do. It's also approved by the manufacturer for both gas and diesel engines. The higher zinc content is beneficial for our flat tappet 4.0 engines, whether during cam break-in or maintaining longevity because it reduces the metal-to-metal friction no matter what the age/mileage. Chevron Delo 400 is a diesel spec motor oil and I've been using it for years in my Jeeps, but especially in the stroker with a mild cam.

Link to comment
Share on other sites

I've run 10w30 Mobile 1 High Mileage and Mobile 1 filters in my Jeeps with great results. It is amazing how clean the oil becomes when drained after a couple years running full synthetic.

 

My TJ has always run full synthetic oil since its rebuild 110k miles ago (except for the first 500 miles when I ran break in oil). To this day, it is still the smoothest and quietest 4.0 I have ever been around. A few years ago I lived in Vail, CO and had several -20F cold mornings and the Jeep didn't struggle to start once, even with 10w30 synthetic.

Link to comment
Share on other sites

Rotella 5w40 synthetic in both my 2000 XJ and my worn out (and I do mean worn out) 1988 MJ.

Been thinking of slapping a poor man's backyard 4.7L together using a fairly decent 81 4.2L and an OK 93 4.0L and see what happens. The 4.0 still has decent bores so going to hack it and skip the machining. Will run the 5w40 as well.

What's the worst that could happen?

 

Hahaha!

Link to comment
Share on other sites

I swear that was the case with the PO of poor old Ratmanche ... Worst I've ever seen for crud inside any engine. I was amazed the rockers could move. The timing chain cavity was even worse. Sad, sad thing. As the rad crumbled in my hands ... He said "it does run a bit hot" ... Ya think?

Link to comment
Share on other sites

A few years ago I lived in Vail, CO and had several -20F cold mornings and the Jeep didn't struggle to start once, even with 10w30 synthetic.

It's not the starting I'm concerned about, I know it'll do that. It's having something lubricating it for the first few seconds of running for every single start between October and April... 10w30 isn't horrendous with a block heater, but 15w40 is pushing it.

Link to comment
Share on other sites

 

A few years ago I lived in Vail, CO and had several -20F cold mornings and the Jeep didn't struggle to start once, even with 10w30 synthetic.

It's not the starting I'm concerned about, I know it'll do that. It's having something lubricating it for the first few seconds of running for every single start between October and April... 10w30 isn't horrendous with a block heater, but 15w40 is pushing it.

 

All the more reason to have a quality oil filter with a good anti-drainback valve.

Link to comment
Share on other sites

Shell Rotella 10W-30 year round and NAPA Gold. This is in my tow '98 XJs. I also ran it in my '88 Comanche. I might be switching to a synthetic in the Purple XJ. I replaced the oil boss oring and the oil consumption seems to be nil. The green one has always been nil, but trying to sell it. Probably use Rotella T6. Something with 1000-1200 ppm Zinc. Diesel oils usually do. I run the 10W30 Rotella in my MB 240D in the colder months. The MB guys say no, but the manual says Yeah. Then they say its not diesel rated. I say read the website.

Link to comment
Share on other sites

 

  1. Someone posted that WIX 51515 is an added capacity filter than the standard 4.0L filter. Also, NAPA dose have a Platinum line for Synthetic oils.

 

 

Oversize Oil Filters (3/4"x16 thread)

 

5.178" HIGH, 3.660" DIAMETER

AC-Delco PF2

Motorcraft FL-1A

Purolator L30001

Napa 1515

Wix 51515

Mopar L-72 L-326, L-526, L-55, L-1007, L-138

Baldwin B118

Hastings LF115

Mobil 1 M1-301

Amsoil EaO15

Donaldson P550008

 

6.93" HIGH, 3.660" DIAMETER

AC-Delco PF42

Motorcraft FL299

Purolator L40017

Napa 1773

Wix 51773

Mopar L-526

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...