Date registered: Mar 2005
Vehicle: '01-E320 & 02-ST2
Location: John 15:18-19
Mentioned: 0 Post(s)
Quoted: 35 Post(s)
There's a guy in the 210 AMG forum that swears by RP's stuff. He claims dramatic increases in fuel economy and smoothness. (I find his claims a bit too dramatic for believability.)
I was curious about RP, so I e-mailed the RP folks, inquiring which of their oils met the MB specs.
Their reply? In order to meet MB specs you have to buy a special synthetic base and then pay MB a large sum of money to gain their blessing. Since they don't want to do that, they can't emblazon their products as meeting MB's requirements.
The guy did opine that their products were "better" than those that meet the MB spec, but...opinions are like armpits, everybody's got them and they usually always stink.
In the end it's like everything else with your car. You bought it, you have to maintain it, you have to make the decision on everything from fuel (why do some people buy a premium car that mandates premium fuel and then dump regular in it?) to other fluids to tires to brakes to car wash and even the air in the tires (some folks swear by nitrogen...).
Me, I tend to follow manufacturer's specs on things like engine oil, etc. However, since engine oil is easy enough to change, it's simply a $75 experiment. At some point I might dump in a crankcase full of RP and run it for several thousand miles. I can't imagine that any oil that exceeds current SAE specs (so long as it is the proper viscosity) would do any significant or permanent damage in 5,000 miles. If you experience an increase in fuel economy and smoothness over that period, then you might reasonably conclude that the RP is reducing friction and protecting the engine just fine. (Caveat: It is typical to see a slight increase in fuel economy just after a synthetic oil change, it usually only lasts a tank or two. Thus, if you still saw better economy after a few thousand miles you could reasonably conclude that is was the nature of the oil, and not just clean, fresh oil.) If you didn't experience any difference, swap it back out with Mobil1.
Since I'm due for an oil change but had already sourced Mobil1 0W40 when it was last on sale, I see no reason to try RP at this point. That said, I'd be curious to see if someone a little less headstrong than the E55 driver would give it a shot.
Re: the MB ATF, it is synthetic as well. Where the AT is concerned, it's far more important to REGULARLY change it since too many people ignore this maintenance item (and dealers won't recommend it, spewing the party line of it being sealed for life). Since it's pretty expensive to change out ATF (and fully change it out) personally I wouldn't roll the dice here. Again, however, if someone was thinking "I'll never change the ATF" vs. "I'll change it but only with RP" I'd support the latter rather than ignoring it. Better to dance with a devil you don't know than to sacrifice your transmission to worn out fluid and clogged filter media, which is a known demon.
Take care and enjoy the synthetic ride,
Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy; its inherent virtue is the equal sharing of misery. (Winston Churchill)
Last edited by Check Codes; 06-18-2007 at 11:01 AM.