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Inline 6 Motor and Oil Types

Black1990jeep

NAXJA Forum User
Location
california
For the Inline Six motor, since she is a flat lifter pushrod type, is a higher zinc,,ie zddp rich , "classic" type oil recommended, today's standard oils are very low in that additive.

In my alternate being, my old air cooled VW is told to be always run with the high zinc specialty oils, because it being flat lifer pushrod type.

What's the story on the XJ inline six?

As to why not run high zinc oil anyway, it can't hurt right? supposedly if that zinc rich oil makes it past rings and/or valve guides it can poison at catalytic converter, ruining it. That is why high zinc oil is being phased out on new cars, along with new valve train designs not requiring as much zinc. In my old VW, it is over six decades old, it has no catalyst.

Thanks!
 
The cats don't like ZDDP plus there is no reason to run "high" concentrations after the cam/lifters have broke in.
 
Ok, On the old VWs Porsches, Triumps I have dealt with, the high zinc old school type oil is recommended for them not just for break in, but all the time.
 
That's not true either, my last 1955cc motor....been building those for 50yrs!
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Just run a Diesel oil. You can get them in the recommended oil weights, they still have decent levels of ZDDP. Works fine. If the higher levels of ZDDP kill your cat you had other engine issues already with oil burning. I run a 15W40 during the summer time (Texas) and a 10W30 during the winter time it rarely gets below freezing around here.
 
I have been running Diesel oil specifically Rotella T6 from Walmart, Walmart tends to be the best price.
 
x2 on rotella t6. 15w-40 summer, 5w-40 winter. Salad on cherokee forum has a Great write up on this subject. All specs on the table there isn't anything that comes close,currently.
yes it has more additives that arent as good for your cat, but really this is going to become an issue in any timely fashion, as far as cat life goes.

One of the best illustrations within his write up are the modern oils, even high mileage ones, and how much they lack for what the i6 requires.

Diesel oil is expensive, But, it goes a hellllllll of a lot longer than anything else. reports are on there to confirm.


run what you like though. the 4.0 is a brute of an engine and even without the best oil, which im guessing 90% of owners at least do not use, will keep the motor running well enough to last long before you see the effects.
 
rotella is relatively cheap here at Walmart compared to the likes of mobil 1, no?

and just using my novice logic, I can't imagine the zinc additive would be bad unless you're actually burning lotsa oil right? or does evaporative loss make it into the cat enough to kill it?
 
You got to think all new engines have roller cams they don't use a flat tappet any more so the engine won't need all that zddp in the oil and the government doesn't want our old cars on the road any more . you can also get some zddp in stp additive or you can get a zddp additive . On a VW and Porsches have a lifter on each side of the cam so that puts alot of where on the cam so it does need a lot of zddp in the oil .
 
I don't think a well broken in 4.0L needs all that ZDDP.

Rotella T6 5w-40 is no longer gasoline rated. Only the T6 5w-30 Muti-Vehicle is, and it is hard to find. You can get it special order from NAPA or O'Reilly's for around $30 a gallon unless they have a sale and it drops to $23 a gallon.

Generally all you need is 10w-30 conventional. Even the Super Tech at Wal Mart is fine. If you want to spend more bucks go for the Pennzoil Yellow Bottle. If you want a synthetic option then the Pennzoil Platinum 10w-30 works very well.

Mobil ESP 5w-40 does work great for extended oil changes.
 
I've always run Mobil 1 synthetic 10w30 all year long. 300k and going strong. (Little bit of lifter clatter though)
 
Diesel oil isn't that expensive. During the summer I run SuperTech 15w40. Oil analysis comes back pretty good on the additive package and it's less than 20 dollars for 2 gallons. I get standard Dino T4 10W30 Rotella from Tractor Supply for less than 30 dollars for 2 gallons. There and ATwoods are the only places I've seen the 10W30 dino Rotella.
 
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