On Mon, 19 Jul 1999, Michel Poulin wrote: > I recently saw the ad on tv for a product called Z-Max. I'm wondering if > anyone has used it and can state if it's just another snake oil or a real Almost all oil additives are, more or less by definition, snake oil. I don't know of any oil additives that aren't. The best thing to do is to check and see if it contains Teflon (or PTFE). Slick 50 is an example of such an additive. DuPont won't let any of the oil makers use the Teflon brand name, because they don't want to get a bad reputation from it. So, the snake oil makers have to buy cheap, imported PTFE and cannot call it Teflon. If you see an additive with PTFE, run away. Of course, not all oil additives have PTFE. Some of them claim to be, for example, simply detergents. These aren't as bad, but they are probably not going to do you any good. Most oil has detergents in it already... The idea behind PTFE oil additives is that it will coat the friction surfaces of the engine, and so during those times when there isn't enough oil (basically at engine startup) the Teflon, which as we all know is very slippery, will prevent the wear. There are a couple of problems with this. First, PTFE is a suspended solid in oil. It does not dissolve to liquid form. This means that what you have are basically little balls floating in your oil. Your oil filter, if it is working properly, does the best it can at removing suspended particles from your oil. This means that one of the primary effects of PTFE is clogging up your oil filter. Secondly, the claim they are making is that PTFE cuts down on engine wear due to friction at startup. The problem with *this* is that although it's true that engine wear occurs mostly at startup, it's not from excess friction, but from chemical reactions. The combustion process makes some pretty fierce acids which eat away at the engine internals. Without the oil to carry these away, wear is increased. Of course, PTFE (nor any other oil additive) can't do anything about this. The best thing you can do to prevent this wear is to let your engine run for 20 or 30 seconds before you drive off when you start it cold, and to use the proper viscosity oil. Stay away from 10W40, even though it may be recommended in the manual; use 10W30, 15W40, or 20W50, depending on conditions. Thirdly, oil already has zinc (and other compounds) in it which serves exactly this purpose. Unlike the PTFE, zinc does not clog up your oil filter. You may have seen the miracle demonstrations where they may put their oil in an engine, then drain it all out and let it run. Studies show (and I can find a source for this if anyone cares, and is still reading) that you can do this just as well with non-treated engines - and that, more often than not, the untreated engines were actually better off than the treated ones. And, lastly but not leastly, oil is complex stuff. It's not just carbon chains - it is chock full of all kinds of polymers, chemicals, additives, etc. from the factory. These chemicals frequently have a symbiotic relationship, where they can work together to achieve more of an effect than either could alone. The oil companies spend lots of money on R&D to get the balances of these chemicals just right. Additives, of course, throw these balances off. > We are looking at protecting our investment in our DeLorean, and would > like to find something that will help keep the engine from feeling the > effects of bad gas, cold starts, and the like... The best thing you can do for that is to drive the car and, when you must store it, to store it properly. Synthetic oil is probably the next best thing you can do. Other than that, just worry about the stuff that's already broken. The PRV engine will easily last for 150, 200, even 300 thousand miles, if it's well taken care of. ------------------------------------------------------------------------ To address comments privately to the moderating team, please address moderator@xxxx