--- In dmcnews@xxxxxxxxxxxxxxx, "Harold McElraft" <hmcelraft@xxxx> wrote: <SNIP> > There are many factors that go into recommendations for an engine > lubricant. The engine tolerances, operating temperatures, emissions, > oil capacity, circulating efficiencies in the engine just to name > some. But the goals are proper flow, protection at high and low > temps, and cleanliness. <SNIP> Absolutely right on all counts here. Not every engine is going to respond the exact same way to every oil. And yes, lubricating technology has come quite a ways since the D first hit the pavement. Both in preventing thermal breakdown, and in cleaning detergents. A great example of that is my car. The first couple of oil changes that I did around the 3500 or so mile marks, the oil was dark, and nasty. Since using regular conventional oils, my oil is now much cleaner, an has gone from a nasty, almost black, to a dark gold color when changing. And it runs much smoother. As far as what brand to use, the most reccomended brands that I've heard are Castrol, Mobile, and Exxon based lubricants, as they come from Gulf Coast wells. I've heard that Pennzoil, and Valvoline are not quite as good, because they originate from Pennsylvania wells that produce a higher parrafin (wax) content. Of course I would assume that strict refinement would remove the wax just the same, but who knows. Since this is speculation, take it as just that. But if anyone has any online resources that could point out differences in brands, please share the links! Manufacturer specifications when it comes to performance/emissions/etc... do indeed play a HUGE part in how the determine what types of oil to use in their motors. Many GM and Ford engines as it seems state to only use 5w30 oil. This surprised me quite a bit too as the vehicles that use this weight such as Grand Am/Prix and Explorers have engines that are designed for performance in either driving fast, or towning. But looking at newer technologies such as more efficient engine/transmission cooling, better filtration, and more efficient internal lubrication, and combustion management computers, engines won't break down, nor dirty the oils are quickly. Hence they can run these lighter oils to decrease emissions, and increase performance. And efficient filtration plays a HUGE roll as well. Learning from past experience with my DeLorean, I only buy filters from the manufacturer. Purflux for the DeLorean, and Motorcraft for the Ford (which they sell @ Wal Mart now). FRAM is junk from several sources I've seen online, and from the photos you can see in the archives of one that failed while it was on my car. Now when it comes to the DeLorean, I myself play it safe, and stick with the factory guidelines. I *might* be able to get away with a lighter oil weight, but what I run works just fine. Going by what the owners manual says, and by how my engine responds, I'm doing just fine. BUT, I do not see a need to ever go below 10w40. The kind of temperatures that warrant that light wieght will probably have such inclimate weather, that your car is going to be in storage anyways. But then again, it just depends upon what your engine likes. If you live in an area where it gets cold enough in the evenings, and the motor runs easier on 5w40, then yes, I'd say by all means, use it. Going over 15w40 is unessisary too, unless you live in the Southwestern Mojave, and drive your car hard in 100+ temperatures. If it gets cold, and you've got 20w50 in you DeLorean, she will be pretty crankywhen you start her up cold. And once you do get her started, the engine will not respond properly. Hit the gas, and shell rev up slowly. Don't give her enough gas, and she'll lug. Plus when running 20w50, I've noticed a great deal more oil spattered on my air filter from the breather hose, and more soot in the tailpipes. The biggest unresolved debate is going to be regular vs. synthetic. Engines designed specificly for synthetic have smaller sized oil passeges that are designed the the smaller, more uniformed HC chains in synthetic. Regular oils will not flow as well, and can hence impeed lubrication in these engines. regular engines can go either way. I do just fine with regular, conventional oil, so I stick with it. Plus the higher cost is a factor too. 7 quarts of syntheic gets pretty expensive. Granted though, you don' have to change it as often. If anyone here can relate some experience in switching their PRV over to synthetic, and can give some details on changes that they've noticed, I've love to hear! -Robert vin 6585 "X"