Originally posted by: steppinthrax
I don't understand it when people say synthetic extends the life of your engine. This is the problem. I've seen cars that have run straight oil go for more then 100 to most of the time 200K if taken care correctly. I think by the 200K mark you would consider trashing the car. My saturn ran for 212K with just straight oil and I would race the engine as a teen.
So how long does the car need to last. I mean if your dirt poor and you can't purchase a car anytime within the next 10 years then I maybe could understand. But before synthetic or before it became pretty common a lot of cars ran straight oil and had thousands of miles....
I generally agree with this. For a non-turbocharged, liquid-cooled, street-only car I see no real reason to go with synthetic since any modern conventional oil will be more than adequate over a reasonable life for the car. With a turbocharged engine, the turbo puts some very high heat loads on the oil and the benefit of synthetic is that it doesn't coke as easily which can extend the life of the turbo. In air-cooled engines, the oil takes a large amount of the cooling load and also sees higher temperatures, which is again a reason to go with synthetic. For cars that are taken to the track, stresses are obviously higher. In most street-driven cars though, the liquid cooling keeps the oil from having to absorb high temperatures and even conventional oil won't break down much.
Any modern street car using conventional oil should last 200,000 miles or more. I've known a lot of mechanics and I still haven't found one who has seen a properly-maintained engine that wore out from conventional oil. (Note that this doesn't include people who went 20,000 miles with conventional oil, or who let the oil get low, etc, as those are maintenance failures not caused by the oil.)
With all that said, there's no functional downside to using synthetic (it costs more, but that's the only potential negative anymore), so if you want the extra piece of mind, there's no reason not to. The stories that talk about synthetic causing leaks are not fully true. Synthetic has slightly better detergency and it flows better, which means that it will make
pre-existing leaks more noticeable, but it will not
cause new leaks.
ZV