ZDP in oil

[mhagie]

Dr Lee, Taking the case of adding zdp(STP 4 cyl oil) to the oil at oil change time does this also apply to the synthetic oils also?
In addition to my project truck I also have a 04 VW Golf TDI that serves me quite well on my 65 mile RT for work, Would that apply to it as well cause the 04 requires a fully synthetic 5w40 found locally in only Castrol and Mobil 1.
Changed at 5k intervals as per dealer instructions.
As usual your thoughts are appreciated.....Merle

[CleviteKid]

If you are using a so-called "universal" oil, that is one that has a spark-ignition rating like SJ, SL, etc. in addition to its diesel rating of CI-4, then its ZDP is restricted to protect the catalytic converter. So it could use a little dose of extra ZDP to lubricate the engine better, in my opinion.

Dr. Lee :cool:

[jbplock]

Dr. Lee,

Do you know of any sources of ZDP besides STP that do not contain VI improvers. I read your excellent http://forum.thedieselpage.com/ubb/icons/icon14.gif write up in the Sulfur: Good, Bad or Ugly ? (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=16;t=000671) topic and now I'm inspired to get some more ZDP in my Dmax's Delvac-1. However, I'm also worried about tinkering with the D-1's VI (??). Your thoughts on this are most appreciated... Thanks!

smile.gif

[Dvldog 8793]

Howdy
I found a deal on the Valvoline Syntech equivilant to STP. Does this product also contain the wonder-drug ZDP? It says that it has "the MOST effective friction additive". Also it supposedly is a semi-synthetic goop so maybe not quit as thick as STP? I can get a case for about the same price as STP, probably a one time offer.
Thanks for the advice!
Conley Janssen

[CleviteKid]

The Valvoline website tries to hide the MSDS's for its products, but I found the Synpower Oil Treatment. It has some zinc compounds in it, but not as much as STP. They claim that analogous organo-molybdenum compounds do about the same thing, so if you want to try Valvoline, it should be OK. It does appear to have some VI improver, which is why I like the STP red formula - the STP red appears to have less VI improver.

Dr. Lee :cool: