Porsche 928: General Information and Recommended Maintenance Intervals

This article applies to the Porsche 928 (1978-1995).

If you own a Porsche 928, you are in a very elite group of drivers. Over 60,000 928 models were produced. Today, there are over one billion vehicles on the road around the world. That means that for every 928 owner, there are over a million people out there who don't own one. Because no 928 has been made in twenty years, parts for it can be expensive and hard to find. Also, all of the original factory warranties have expired. By following a few maintenance suggestions, you can keep the need to find and pay for replacement parts at a minimum. This article provides information on how to maintain the one you drive.

Engine Oil and Filter

Porsche's original recommendation in the owner's manual was to change the oil every 15,000 miles. That was based on what the Porsche engineers felt was right for the engine at the time. Today, the youngest 928 engine is over 20 years old. People drive differently from one another, they live in different climates and locations; therefore, more care has to be given to the engine oil. Some 928 owners change the oil and filter every 3,000 miles, while others do it once a year, or at 12,000 miles. The important thing is to monitor your oil. When you check it, what color is it? Do you do a lot of stop-and-go city driving? Are there extreme weather conditions where you drive? Most current 928 owners say they change the oil and filter every 3,000 to 4,000 miles, or at six months. If you prefer to change oil annually, you may want to change the oil filter halfway through the cycle. The main thought here is that spending $100 or less on an oil and filter change is much less expensive than an engine overhaul. Keep your engine happy.

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Spark Plugs

Depending on the engine, spark plugs are recommended to be changed at 60,000 miles. Again, this number depends on how you drive and your driving conditions. Because they are vital to your engine's performance, they should be checked every 30,000 miles or so. Even one bad plug can cause rough idling, poor acceleration, and stalling. Contaminants in the fuel or air mixture in the combustion chamber can lead to a build-up of carbon or sludge on the tip of the plug, diminishing performance.

Air Filter

Many drivers overlook one of the most critical parts of the 928: the air filter. While driving, air is sucked into the engine compartment from very close to the pavement. All types of dirt, debris, and oil particulates accompany the air toward the engine. The air filter traps them before they can make their way to the fuel injectors, possibly jamming them. The manufacturer recommends changing the OEM filter every 15,000 miles. Most 928 owners recommend changing them every 30,000 to 45,000 miles depending on driving styles and conditions. If you are uncertain, you can inspect the filter for excess dirt or deterioration. Replacing it yourself will cost less than $50, depending on the type of filter you buy. Having it professionally done will cost around $100, again depending on the filter.

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Timing Belt

The timing belt makes sure the moving parts in your engine work together. If a belt snaps or becomes loose, the engine may need major repairs. Porsche recommends that you replace the belt every 60,000 miles, with frequent inspections before that is reached. You'll find that most 928 owners like to service it at a more conservative 40,000-45,000 miles. Once again, how and where you drive may adjust these numbers. Unless you know what you're doing, because you have to remove a number of items to replace the timing belt, it might be a good idea to have it done professionally. It will cost around $1,000, but it will be worth it.

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Brake Fluid

Over time, air and metal particulates can seep into the fluid, causing markedly decreased brake performance. Most Porsche owners suggest that you check your fluid every 15,000 miles. If your braking seems soft and/or the fluid you can see in the brake fluid reservoir appears dark brown, you will need to bleed your brake system. This requires a flush of the entire braking system and the introduction of new brake fluid into the lines. It is a job you can do yourself, but if this is the first time you've done this, you may want to have someone who has done this before help you. If you do it yourself, it will cost about $10-$45 for materials and will take less than an hour. Having it done professionally will cost you $75 or so.

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Tires

No matter if you have 15, 16, or 17 inch wheels, a set of new tires can be an expensive proposition. A set of four tires can cost well over $1,000. Your tires can tell you how they're doing by looking at them before you need to replace them. Inspect them every few thousand miles. This chart from Terry's Auto Service can help you read what your tires are saying.

Be sure that your tires are neither under-inflated or over-inflated, as this leads to excessive wear. Experts suggest rotating your tires every 5,000 to 7,000 miles to even out tire wear. Of course, if you're on a track every weekend, you'll experience different tire wear situations. To check your tire's tread depth, use the penny trick. Place a Lincoln head penny between the grooves on your tire tread, if you can see all of Lincoln's head, you have less that 2/32 of an inch of tread left. Time to get a new tire.

Power Steering

Just as it is with the brakes on your car, your power steering is boosted through hydraulics. It also helps to lubricate the steering mechanism. Dirty fluid can result in poor steering and whining noises when turning. Located near the front of the engine well, the power steering fluid reservoir is translucent. You can see markers on the side of it that can tell you when you need to add fluid. You should think about changing your power steering fluid every 30,000 to 40,000 miles. It can be the same fluid that powers the automatic transmission. Most Porsche owners use either Dexron VI ATF ($5.00 to $8.50/quart), Pentosin CHF 202 ($16.00 to $20.00/quart), or any synthetic ATF that meets the original Dexron III standards. If you don't intend to flush the whole system, one quart should be enough to fill it.

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Fuel Filter

The lining of underground fuel tanks and anti-leakage legislation have markedly decreased the amount of contaminants in gasoline. Still, sluggish performance may be a symptom of a blocked fuel filter. The original recommendation for replacement was 60,000 miles. Most 928 owners change them before that. Some change them about once a year or 15,000 miles. The fuel filter is located near the gas tank at the rear of the car. To access it, you need to safely raise the rear passenger side of the car. Take the tire off and you will see the pump filter access panel. Removing the panel exposes the fuel filter that is secured next to the fuel pump. Carefully disconnect the hoses going in and out of the filter. Be wary of spilling gas that may be still in the filter. Undo the clamps holding it to the car and install the new filter. New fuel filters for a 928 run from $16 to $24.

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Related Discussions, Sites, and Video

• Porsche 928 Service Schedule - Driverside.com
• Tire Maintenance Guide - Terrysautoservice.com
• 928 Fuel Filter Installation - 928gt.com
• 928 Owner's Manual Online - Rennlist.com
• Timing Belt Procedure - Rennlist.com
• 928 Replacement Air Filters - Tunersdepot.com
• 928 Maintenance Schedule - Pelicanparts.com
• 928 Water Pump/Timing Belt Change - Pelicanparts.com
• Replace Power Steering Fluid - Rennlist.com
• How Often Should I Change My Spark Plugs? - Youtube.com