In the past, manufacturers recommended changing your spark plugs every 30,000 to 40,000 miles or so. These days, with modern automotive technology, that has changed up to every 100,000 miles in many cases.
Modern automobile engines run so efficiently that the typical owner doesn’t even give spark plugs a second thought unless they bring it in for service to the dealer they purchased it from who reminds them of the proper intervals to change their plugs.
If your customer is not a regular, and you don’t know the history of the vehicle, It would be wise to ask your customer if and when they last changed their spark plugs if they are near the 100,000 mile point on the odometer. You need to explain to them that If they wait too long, there could be misfires that lead to all kinds of issues that could lead to more expensive repairs. Of course, whenever you change the plugs, it’s a recommended the wires should also be replaced.
Let your customer know that if they don’t get this important job done early enough, it also becomes more difficult to extract the plugs, and they freeze up in the cylinder from build-up. If there are problems extracting the plugs and you ruin the threads, the repairs can be more costly.
When your customer’s vehicle is up on the Automotive Lift, and the mileage meets to criteria, it would be a good idea to make the recommendation to change the spark plugs now, instead of waiting for something to demand the task. A little preventative maintenance goes a long way.