Miata Mailing List: May 1997, Message #84
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From: 	Jim Wirt <jwirt@ucsd.edu>

Subject: Re: Synthetic oil

Date: 	Thu, 1 May 1997 12:23:19 -0500



When my wife's 93's valve clatter was brought to the attention of

the dealer they suggested using a lighter weight oil.  This didn't

sound like the best colution to me.  I switched to a 10W30 synthetic 

on the first oil change at 2000 miles...no more valve clatter!  

I have used synthetics exclusively in my '86 Merkur XR4Ti and when 

I examined the turbo at about 115K miles it was like new...no coking, 

no excessive wear.



>Does synthetic oil need to be changed more often than standard 

> oil? 



You should change it about as often as regular oil (IMHO).  

Even though synthetics don't break down at high temps like 

regular oil, you still accumulate combustion byproducts in 

the oil: things like acids and such that a filter will not 

remove.  You might go 1K or so more on the synthetic, but even

the manufacturers don't seem to claim the "1 year/20,000 miles 

between changes" for synthetics anymore.