We all know how important it is to change your engine oil and filter every 3,000 miles but there is more to maintenance than oil changes.
The following are some often overlooked maintenance items. They are all due every 2 years or 30,000 miles on most cars:
- Brake fluid flush
- Coolant flush
- Transmission fluid exchange
- Fuel filter
- Spark plugs
Changing old fluids and clogged filters are a no-brainer but changing spark plugs is getting to be a controversial subject. Mostly due to the introduction of the 90,000 mile platinum spark plug. These are spark plugs with electrodes that can last 3 to 4 times longer than conventional spark plugs.
We’ve been seeing a couple of problems with cars that use these spark plugs. One problem is not being able to unscrew the plugs because they have galvanized themselves to the cylinder head. This can happen because the spark plugs have been left in the engine so long that they have become part of the head. When a spark plug is stuck it can either break off or come out very hard taking the threads in the head with it. In a case like this it is likely that the head will need to be removed and sent to a machine shop to have new threads installed. We have also seen many cases where the porcelain insulator will deteriorate and leak spark well before the 90,000 mile service interval. This usually causes an engine miss and a “Check Engine” or “Service Engine Soon” light to come on. Any time you have a “Check Engine” or “Service Engine Soon” light illuminate on an OBD2 computer system you are in for an expensive adventure. OBD2 cars include some 1995 and all 1996 and newer vehicles.
Considering these examples it would be much more cost effective to change spark plugs before they cause trouble than to wait for them to act up. We recommend never leaving spark plugs in for more than 30,000 miles on most cars.
When this stuck spark plug broke off in the hole it turned a routine job into an adventure.
This 100,000 mile spark plug was removed at 56,000 miles. The black stripe on the insulator is a carbon track left behind from spark leakage. It was causing a severe engine misfire and a “Check Engine” light to come on. This can cause thousands of dollars worth of damage on an OBD 2 vehicle (most cars built past 1995 are OBD 2).
Here’s a 100,000 mile spark plug that we removed at 60,000 miles. Note the cavity in the negative electrode. The contact that used to be there has completely eroded away. Worn spark plugs put such a load on the ignition system, they can cause many other expensive components such as ignition coils and ignition modules to get over-loaded, causing them to burn out or fail prematurely. A new spark plug with electrodes in tact.