|
I've been trying to figure this one out. The plug replace interval is listed as 5 years or 60K miles, whichever comes first.
Lets say you are the proverbial "little old lady" that only drives her BRZ/86 back and forth to church on Sunday and put's maybe 5K a year on her car. That comes to 25K miles in 5 years or about 100 miles a week. Well within the realm of possibility so long as she doesn't live too far from church. Applying those numbers to the maintenance schedule tells me that even when driving half the distance, she would still need to replace the plugs in five years?
This got me to thinking. The miles or months, which ever comes first, rule might make sense when it comes to something like fluids, but not so much for spark plugs.
My first thought was maybe the plugs in a boxer engine wear out at the same rate whether the engine is running or not. Since that didn't make much sense, I came to a second conclusion.
Maybe the manufacturer assumed that if you only drove a few thousand miles a year, most of that driving was probably in the city under stop and go conditions, and that type of driving wears a plug out faster. Since I'm not a mechanic or an expert on spark plugs I was not sure about this theory either.
My last theory was that just maybe the maintenance schedule was designed to help Toyota/Subaru stealership's take your hard earned money every five years replacing something that didn't really need replacing.
Someone please enlighten me, I would shudder to think my last theory was the correct one.
|