Spark Plug Replacement Intervals - Why?

[Blang]

What am I not reading well?

What am I not reading well?

The thread might not have been updated when you made your comment. During that time he said he would get some plugs and get it done soon. He got a satisfactory answer from @SC Maintenance

 

[BHopkins]

Most service intervals are intended to keep the equipment, in this case a car, running at optimum performance. In ideal preventative maintenance, wear parts are replaced before they start to fail, instead of after. In calculating PM service intervals, variation in failure rates has to be considered, and a conservative PM service interval is used, to assure that the majority of parts that may fail before the mean failure rate, are also replaced before they fail.

Some, like yourself it seems, may be comfortable with waiting until performance starts to degrade before changing parts. Sometimes, like engine air filters, there is minimal risk of doing service this way. But other times, waiting until performance degrades before doing service, caused premature failure of other parts. For example, waiting too long on an oil change. I suspect spark plugs on modern cars is one of those that can result in premature failure of ignition coils.

 

[BHopkins]

I didn’t come here to argue, I came here to get a reason besides “the manual says so”.

Okay, so the coils will run hotter - is that necessarily going to kill them sooner? Will it manifest itself in some other way than a drop in fuel economy? Is there some other indication of worn plugs that is readily apparent?

What am I not reading well?

 

[HemiBenny]

The Auto manufacturer and plug manufacturer give the life expectancy of the spark plug! It's a known maintenance routine that must be performed! It's not that expensive and doesn't have to be done that often!
Ignore it, and it just cascades into other issues that cost money to remedy, or at the very least, you'll have to change plugs when it's not convenient for you.

Anyway, Cheers!

 

[Jetronic]

Again - I see no drop in mileage. This would obviously be the first indication of electrode burn-back, and it doesn’t seem to be happening.

I have a degree in mechanical engineering. I get that things wear out - but I also know that they give indications that they’re wearing out. I don’t accept replacing a widget that’s still fully functional just because somebody put a replacement interval in a manual.

I would prefer to replace them at a convenient time for me, and not find out they're no good half way up the Brenner pass. I'd at least check the plugs around interval time.