I've used (and only used) Castrol GTX in a jeep I owned and the engine lasted to 250,000 miles (although the tranny didn't keep up). Slick 50 is the worst thing to use. Think about it....it has teflon particles in it (not blended into the oil but suspended particles). What is the job of the oil filter? to remove ANY particles that are in the oil to protect the engine. That there is a waste of money since you are filtering out all that "protection" that was added to it. Any engine will last 200,000+ miles if you take care of it and change the oil at the recomended intervals. As for synthetic oil...it's ok but you will have a few oil leaks that will spring up after putting it in. One of the main places I can think of is the seal that is behind the main crank pulley in the front of the engine. This is already notorious for leaking with regular oil. Synthetics flow nicer then regular oil and that's why it's better and that is also why leaks you never had before will appear. For any transmission stay away from additives. I remember speaking to a friend of mine who was a mechaninc and he told me that almost all the additives out there for transmission will either rot the seals out or casue them to swell up. Just use regular Dextron III transmission fluid. Remember if the additives would be better for the car and make the parts last longer don't you think that the manufacture of the car would put them in so that they could offer better warranties or have lower repair rates on warranties? So to sum it up....Regular Tranny fluid for the transmission and either Regular motor oil or Synthetic (your choice) in the engine...NO additives! Remember that the synthetic oil MAY FIND a leak that has been able to get away with regular oil. I say find and not casue becasue synthetics don't casue a leak (like rot out a seal or something) but finds an exisitng one that regular oil was not able to get through. Steve --- In dmcnews@xxxx, "iqmpike" <iqmpike@xxxx> wrote: > Quick question for the group... I have heard MANY storied on what > kind of oil to put in the Delorean.. I have heard 10W50, 5W30, etc... > > I went and bought 7 quarts of Penzoil 5W30 SYNTHETIC oil.... > > My car has 5300 miles on it. > > Is synthetic OK to put in a delorean, or is regular oil better?