You always have a bit of leeway in maintenance matters, but it’s a good practice to follow what your vehicle manufacturer says are the proper replacement parts at the proper replacement intervals. This is particularly true for fluids and ignition components.
“Your manual may say INSPECT the plugs every 15k miles…but REPLACE…I don’t think so.”
For most 6-cylinder car, be it a sedan, a SUV or a minivan, it is a terribly difficult job to access some, if not all, spark plugs of the car.
Especially for the new cars of recent years, as the CENTRAL high-voltage Distributor having been replaced by multiple Local high voltage coil sitting on top of the accessing hole of each spark plug, accessing the spark plugs of the 6+ cyls car is a soul-testing task. Those who can pass the test like this is qualified to be in the Vatican saints list.
I know a 25+year experience mechanics once did the tune-up job for a 10+year old GM 6-cyl van. After spending 30 minutes to ONLY take out the most tough plug, what he saw was a spark plug with its center electrode much thinner than a hair.
Obviously none of the mechanics who did the maintenance job for this van in the prior 10+year had ever bothered to touch that inaccessible plug at all. Maybe some ones had tried for 5 minutes, I guess. When the manager asking ?Joe, is the van ready yet? Customer is urging now.?, so behave will a normal human being ?What the f#$%k, I can?t do this replacing job, nobody can do double check of this plug, either. Why bother??).
Anyone who want to do INSPECTION of the spark plugs for vehicles like this certainly need to ask help from Vantican.
Besides, even if the plugs is/are not hard to access, taking out a plug and then ask it to go back to work is still not a good idea. Spark plug is composed of two, at least, drastically different materials; namely, the metal and the ceramic. And spark plug is working under very high stress & temperature condition. Expansion coefficients of the material and ceramic are no way to be 100% the same. Putting a 15k miles old plug back to the torturing environment is risking of the danger of ceramic fatigue in the form of crack/brittle. If that happens, and the ceramic debris fall into the combustion chamber thru the plug hole when you are taking the broken plug out, the engine is very likely to be declared RIP.
My way of handling spark plug is either let the plug take the early retire or let it work as long as the manual suggests. I will never take out a plug and then reinstall it to the engine. Spark plug is so cheap in these days, it just isn?t worth the effort and the risk.
I pretty sure the manual was suggesting how ofter you should check your spark plugs. The year make and Model of the car are important factors in determine how often you should make the change. Another important factor like any other maintenance is the wear and tear you place on your car.
I definitely think there is still a need for a good web-based automobile maintenance tracking solution. I’m putting together a discussion group to learn what people want to track about their vehicle, and see if there is an opportunity to build a solution to meet those needs.
If anyone is interested in participating please sign up here: http://bit.ly/fivbYv