Originally Posted By: stock49
Originally Posted By: Lifeguard
How much ZDDP does 8oz of EOS add to 5.5qts (using the 1qt filter instead of the 0.5qt) add to 800ppm ZDDP oil?


I haven't found any official GM pubs (like an MSDS) that document ZDDP content. There's an interesting article over at the SlantStix website which suggests some fairly precise measures of zinc and phosphorus content in EOS. It also gets into the arithmetic involved in using EOS in order to 'top-up' the ZDDP levels in a given oil formulation.

The article also contains some broken links into the SAE website. Fortunately a google search on SAE and the corresponding paper number will get you to the new location - e.g. "SAE 831760".

Update: I found a working link to an older image of the MSDS for EOS over at the VR6 racing site. It dates to '89 and shows that GM was using Lubrizol's ingredients - with ZDDP at 5% by weight.


Thanks, more reading to do. I got my spring grease and oil coming up, and I'm shopping for the best deal on the oil and filter. Found the Wix 1qt pretty cheap locally and a deal on Valvoline grease that meets GM specs, just picking an oil now.