reply to ArgyleDSL
Re: Why can Porsches go 20K between oil changes? The owners manual for my 1986 mazda 626 says to change the oil every 7500 miles.
last time I change to oil I used synthetic oil.
My wife's 1998 Volvo s70 states if you drive in the city change very 5000 miles if you drive mostly highway then 10000 miles.