What Type of Oil do you use?

[James P]

I have been looking around and am wondering what type of oil works the best in these jeeps?
I found one post about some one mentioning using Rotella T in their jeep and am wondering what people are using.

Now I understand which weights to use and all that just wondering is there is something specific to be using. I am getting ready to do an oil change before I fire up the jeep when I get the float I just bought.

A side note if Rotella is fine that is cool because that is what I run in my diesel truck and I buy it by the 5 Gallon bucket.

[Carls_jeep]

I have been using Rotella T 15w40 in everything since the late 1980's. It's probably the best oil you can buy.

[aboyandhisdog]

http://cj-3a.com/forum/YaBB.pl?num=1331142542/0#0

I might be the only one, but I'll stand up for synthetic oils. �I am as much a believer in synthetic oils as some are believers in the diesel oils. �I'm still experimenting with weight, however. �The 10w40 High Mileage Mobil 1 is working great now but I might try the 15w50 Mobil 1 at my next oil change just to see if I can even tell the difference. �Use whatever YOU think is best.

[calvinhunt]

I'm another who is very impressed with Rotella T 15W40.

[rocketeer]

The most important thing is the additive ZDDP, because of the mushroom tappets. Use oil designed for diesel trucks, which has a higher content of ZDDP, or add it seperately.

Larry

[Carls_jeep]

Yes, what ever brand you use do a search or call the company and ask if it has ZDDP in it. Rotella does have it and I think Chevron 400 has it.

[athawk11]

I use 4 quarts Castrol 20w-50  HIGH MILEAGE and 1 quart Rislone ZDDP treatment.  (On the shelf at: Advanced Auto)

My results:  I really like the high mileage oils.  I haven't had to add a drop of oil after approximately 400 miles of driving. I was leaking a bit from my rear main prior to using the high mileage.  While using 5w-30 I would loose a quart every 100 miles.

I would like to kill three birds with one stone using: Synthetic--High Mileage--with ZDDP in the 10w-40 to 15w-50 range.  

If this oil exists, I haven't found it yet.  I couldn't even find a synthetic high mileage.

I think I will try the 10w-40 high mileage on the next change.  It may help my MPG a bit.

Tim

[aboyandhisdog]

Hawk,

Mobil 1 has a synthetic high mileage in 5W30, 10W30, or 10W40.  They also have a 15W50 but it isn't a "high mileage" formula...and you may want those seal conditioners which may explain your lack of leaks.  My Advance Auto up here carries all of them and the other auto parts places all seem to carry Mobil 1 but don't stock ALL of the formulas.  All of these have sufficient zinc and phosphorus for these jeeps.  Don't think you'd need the additive, but it's your call.

[CJPilot]

I use 4 quarts Castrol 20w-50 �HIGH MILEAGE and 1 quart Rislone ZDDP treatment. �(On the shelf at: Advanced Auto)

Tim

Nice way of getting everything. I think I'll try that

Steve

[athawk11]

Steve, give it a shot, but as others have mentioned, I have heard nothing but good on the Rotella T.  It just didn't give you a high mileage option. Castrol high mileage 20w-50 may be a smidge heavy, but I figured it would help during the hot summer months.  These are old engines.  I'm going to give it every chance I can to live beyond me.

Yeah, Tom, I think you're right. I did spot the Mobil 1 High Mileage Syn. on the last change.  You had convinced me to try synthetic,  but I had convinced myself I wanted a high mileage with at least 50w on the high side.  That's where I got stuck.  Now I think 10 to 15w40 would be sufficient.  I, like you, am toying with the weights a little.  When it's time for your next change, and you do go 50w, let me know how your Willys feels.

Tim

[Chasm]

I am using straight 30 weight (non-detergent) for vintage engines. I have a fresh rebuilt Kaiser Willys CJ3A core (see other threads about my cracked block) and am using what the original owner's manual called for. I am going to stick with it and see how it performs. So far, it is doing well through its 2nd oil change.

[johnrb3b]

I've begun using oil from the Classic Car Club of Am.

http://www.classiccarmotoroil.com

They've specified an oil to be made for them by one of the racing lubricant companies.
Two important characteristics.
High ZDDP content - 1,600 ppm. Well above the minimum needed for flat tappet engines.
Additives to combat moisture (condensate) which is a problem for engines that sit more than run.

Cost is very competitive with Chicago area auto parts stores.
I quit using Rotella when the ZDDP content dropped below 1,000 ppm. There are still a couple of oils to be found with enough zinc, but it's lots easier to just order Classic Car Oil over the phone.