Motor oil warning!

[OGCollard]

If anyone wants to know here is the response from shell. I asked: Do your high mileage motor oils contain zinc and phosphorous that would be good for flat tappet engines?

They responded: If you are seeking higher zinc and phosphorous contents you may have to look to a racing oil. We have a product that is called Pennzoil Racing Motor Oil and is available in SAE 25W-50. It has approximately 1800-2000 ppm of zinc additive for extra wear protection. Other engine oils with comparable anti wear protection would include Shell Rotella T 15W-40.
The zinc and phosphorous levels were recently reduced (from the API SL levels) as there has been concern that the oil that makes its way in to the combustion zone of your engine, carrying these anti-wear metals was burning and poisoning the catalyst in the catalytic converters.
Should you desire to speak with a technical representative to discuss this issue in more detail please call Pennzoil-Quaker State Technical Information at 1-800-237-8645, option 32.


Dont know if this helps but guess I wont use Pennzoil high mileage in my jeep anymore.

[prerunner1982]

Rotella T is what I use.

[OGCollard]

Not to be selfish but I read somewhere that this issue was more important to Jeeps 97 and older....do I need to worry about it with my 2000 Cherokee 4.0?

[prerunner1982]

as far as I know they use the same flat tappets that the earlier 4.0 liter does... could be wrong.

[4.3LXJ]

They do use the same tappets. Any old school engine like the 4.0, or my Chevy 350 and even my Subaru engines have this issue. After reading the above post from a Shell guy, I was surprised to hear that the cats are fouled by those metals. Mine has not been. I have also had an oil rep from Valvoline tell me that the new formulation was due to most engines using roller cams now. But they again, they put these additives in most of their oil and have the highest amount of them available in their racing oil, which I highly recommend

[Rocco83]

I've used Shell Rotella T5 in all the Jeeps I've owned and have had no problems. Worked for me so far so I'm not changing.

Also use Wix oversized filters and only change my oil every 7500-8k miles.