i will give you a simple logical response to this question--------to answer why you should or should not add any zddp to your older cars oil is simple--------if you are using oil that is rated and designated for use in new cars the answer is an ablolute yes if you really want to protect it--------modern oil is specifically formulated for newer engines that have been designed from the ground up to use oil with less zddp--------your engine was designed by engineers that knew that the level of zddp in the oil you would be buying would be the same as it had been since the early 50's---------they could not have envisioned the large scale reductions that were the result of tighter emission controls--------if you are spending the extra money to buy specialized oils that are formulated for older engines with extra zddp there is no need to add the extra zddp as long as the amount is actually adequate and you can trust the manufacturer---------i have been accused of creating a scare for the sake of profit by marketing ZddPlus--------nothing could be further from the truth-------fact is that i first sourced large quatities of zddp for my personal fleet of TR's after doing serious research into the issue-------it was later at the suggestion of others that i go to the bother of marketing it as an additive for others-----------i could see how someone might be led to believe i made this up but it would be hard to believe that all the oil companies followed suit---------since most of the nascar and other racing teams either use Joe Gibbs or Valvoline racing oil with extra zddp or add zddp in the form of ZDDPlus it is a far reach to believe these companies jumped on an empty bandwagon--------the facts are, that used in proper amounts, ie about 1800-2000 there are no negative side effects from using zddp in oil----------it does not clog orifices, gum valves, foul spark plugs or ruin O2 sensors-------i can create buildup on ring lands if used in excessive amounts IF the engine has excessive blowby but if thats the case you need a rebuild anyway---------it does reduce catylic convertor life--------- thats why oil companies are contuining to reduce the zddp---------for a while it was considered wise to use diesel formulated oils since they usually contained higher amounts of zddp-------aside from the fact that they also had other additives that made them less than perfect for high performance gasoline engines even the newer formulations of diesel oil have much lower amounts of zddp--------and this fall when the newer GF-5 SN passenger car oils come out the protection for older cars will be reduced even more--------if you think that the same govt that brought you the "cash for clunkers" program really gives a darn about your 80's turbo regal i suggest you think again--------is it different than any other product???---------there is no mystery------its not a new invention-------its been around for many decades--------it is not a new miracle additive like is sold on tv-------opinions????--------whats to need---------how about some common sense???-------look at the facts instead of some ex racer on TV hawking some additive by running his car around the desert without oil because he used some miracle additive---------the auto parts stores are full of miracle additives that do little to nothing yet people by them by the millions--------none of these miracle additives have ever been important enough for any company to actually consider using them in oil formulations or for car companies to require their use for warranty reasons ----------humans are so gullible and illogical----------the lottery proves it everyday-----------read the tech papers on the ZddPlus website------those are not sales brochures but honest technical papers written by dedicated engineers that are also old car lovers..................RC
