How often should you service your car?

How often should you service your car?

“One hundred thousand miles before the first scheduled tune-up!” “Coolant that lasts the life of the car!” These seem to be the mantra of the marketing gurus of car manufacturers today. They promise cars that last forever, yet cars still break down consistently. Why this disparity? Why do our cars break down when they are supposed to last a long time without regular maintenance? This marketing ploy has created a lot of confusion. Allow me to bring some sense to it all.


First, there’s no such thing as a tune-up anymore. Years ago when cars operated on point ignition systems, yes the tune-up was necessary. Having a tune-up meant that the ignition system got new parts, filters, sparkplugs, wires, and so on. Today, with computerized ignition, most of the traditional ignition components are gone. Points, condensers, distributors, caps, and rotors are a thing of the past. All this stuff has been replaced with an intuitive computerized ignition that manages fuel and ignition automatically based on sensor input and environmental conditions.

What this marketing ploy refers to is sparkplug replacement. That’s it. Most carmakers use platinum sparkplugs today because they last longer and have a hotter spark. And, yes, platinum spark plugs under perfect laboratory conditions probably would log 100,000 miles before giving up the ghost. But we’re talking real world here. Enter the effects of bad fuel injectors, cold weather’s effect on fuel mixture (richer mix) that fouls out the plugs, faulty sensors that cause incorrect engine adjustments (which fouls out plugs), mechanical malfunctions such as bad valve guides and seals that spill oil on the plugs (causing misfire), and worn pistons and rings that cause oil consumption (as well as poor performance and decreased fuel efficiency). Then, of course, we have air and fuel filters that get dirty and cause engine performance to go south as well. Oh, and what about the effects of bad gas?

Add the fact that most engines today are made of aluminum and the sparkplugs are made of an alloy metal, and when you ignore them for a long time, these dissimilar metals (of the cylinder heads and sparkplugs) “weld” themselves together, making them extremely difficult to remove and subject to cylinder head damage.


Twelve years ago GM introduced an engine coolant called Dexcool. It’s supposed to last five years or 150,000 miles, but there have been problems with it. Cooling systems that use this coolant have experienced more acid buildup and rust in the system. The acid eats away at gaskets. Rust builds up in the system, inhibiting the flow of coolant flow, which causes overheating. Overall, numerous cooling system problems have been attributed to the use of this controversial product that GM sternly stands behind. There are class action suits against GM on this issue, but no settlement has been made to date.

So how often should you service your car?

Let’s take a closer look on most frequantly changeable parts.

Air filters have always played an important role in automobiles. They keep harmful, abrasive dust and dirt out of the inside of the engine where it can do a lot of damage. However, they are even more important today with sophisticated computer-controlled fuel injection. A clean air filter is absolutely necessary to maintain the delicate balance of air-to-fuel ratio in a fuel injection system. A dirty air filter causes the fuel delivery system to go haywire trying to maintain balance.

Recommended replacement interval: Every 10,000 to 15,000 miles unless otherwise specified.


With the increase of airborne contaminants, carmakers have designed more sophisticated air filtration systems in vehicles. They have installed cabin air filters in a lot of their models to filter out air impurities such as pollen, dirt, grime, and the likes. The cabin air filter is usually located under the hood inside the cowl area close to the air intake for the HVAC system (heating ventilation and air conditioning). The recommended replacement interval for the cabin air filter is around 15,000 to 20,000 miles, unless you live in a dirty, dusty environment. If that’s the case, replace it a little more often based on visual inspection.

The oil filter is the storehouse for dirt in the crankcase. It traps dirt, metal filings, and sludge (all are by-products of the internal combustion engine). Without this filter, these contaminants flow through the engine causing friction, heat, and ultimately premature engine failure.

Recommended replacement interval: Every 3,000 miles. Note: Always replace the oil filter with an OEM-quality filter that mimics the OEM design. This design has check valves to prevent “dry startup” (if so equipped) and fine-filtration filter media to filter out the tiniest speck of harmful dirt or grime.


The automatic transmission is a mechanical wonder in its design and function, making your car go forward and backward. The automatic transmission is nothing more than a giant hydraulic pump that lubricates itself. The fluid follows a pre-determined path under hydraulic pressure, creating what is called a “fluid coupling” or linkup between the engine and transmission, propelling the car forward. In order for all this to happen, the fluid must be clean and flow freely. The transmission filter plays a major role, keeping the fluid clean of debris such as dirt, sludge, and clutch material. A clogged filter inhibits the flow of fluid, causing the pressure to drop, the fluid breaks down, and friction and heat buildup, which affects the performance of the transmission (or worse, the transmission fails). It is extremely important to keep the filter and fluid in your transmission clean.

Recommended replacement interval: Every 25,000 to 35,000 miles.

Proper maintenance is essential if you want to make your car last and save a lot of money in the long haul. For maximum life, follow the severe service schedule of your owner’s manual. When the service schedule suggests an extremely long service interval (in excess of 100,000 miles), get the advice of your service professional.

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