[rohrt]

I switched to Rotella T 10W-30 in my classics several years ago. The price was right so I have been using it for all my cars.

The kid behind the parts counter has been giving me a hard time about using a diesel oil in my cars, so I decided I should look up why I started using it in the first place and either prove him wrong or find out why I shouldn't use it.

So digging into the reading this morning I found this info from a Shell rep.

"Passenger car motor oils had approximately 1200 ppm zinc prior to 2001. In 2001 the zinc was reduced to 1000 ppm and in 2005 reduced again to the current 800 ppm.
Thus, the new Rotella T with triple protection 15w-40 CJ-4 has the same zinc content that passenger car motor oils had in 2000 before the current problems with flat tappets began.
However, zinc compounds are not the only additives that can reduce wear. We were able to reduce wear approximately 50% with the new Rotella T with triple protection 15w-40 CJ-4 formulation."

So this is why I was using. Now as to why not to use in my daily driver. These are reasons I found.

* high levels of detergent (sulfated ash)
* increased zinc was causing failures to the exhaust valves
* reported excess oil consumption
* damaging emissions parts for making hazardous compound to spew into the air. Thus ruining the catalytic converter

I have not noticed any problems with any of my vehicles but this info does have considering changing oil.