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
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
Dr. Lee,
Do you know of any sources of ZDP besides STP that do not contain VI improvers. I read your excellentwrite up in the Sulfur: Good, Bad or Ugly ? 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!
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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
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
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