What You Need To Know About Buying a Used Porsche Boxster
If you’re in the market for a used Porsche Boxster, our guide will help you find the bargain and avoid the bad investment. Buying a used Boxster is certainly one of the most affordable ways to become a first-time Porsche owner. There are risks if you’re not cautious, but with some insights and careful shopping, there are bargains to be had.
Twenty Years of Opportunities
The first-generation Porsche Boxster is heading for being 20 years old. However, the Boxster platform exists right up to the current production 718. As a result, there’s extensive knowledge available of common mechanical problems with these cars and therefore, it’s possible to sort the good used Boxster from the bad. The good news is the Boxster is generally reliable and has aged gracefully.
Pre-purchase Inspection – PPI
The first step, once you’ve identified a candidate, is to get a thorough inspection by a local expert. The pre-purchase inspection is designed to identify mechanical problems that may not be clearly evident at first glance. In our buyer guide below we’ve extensively highlighted those potential issues to be on the look out for. Getting a repair history on the car, if available, is helpful and will instantly identify or eliminate potential problem areas.
The number of owners doesn’t necessarily matter with a Porsche – the work and records performed do. Many owners are enthusiasts and will keep all the invoices from services or repairs.
If the seller wont let you inspect the car, walk away.
Mileage and Service History
In 20 year old cars, higher mileage is not necessarily a bad thing. In fact, a Boxster that has been effectively used, could be in a more superior condition than one that has an attractively low mileage reading. Low mileage cars can have hidden issues, so you’ll want to take a good look through any documented history available. A recognizable pattern of servicing on higher mileage cars is essential. On the lower mileage cars, timed intervals between services is the key indicator.
Low mileage cars can miss their planned service intervals and despite a lack of miles, significant wear and tear can take place. Look to see when the last time the plugs were changed – 10 years is the limit before plugs must be replaced. The brake fluid should be flushed every 2 or 3 years. Check the DOT on the tires – lots of tread doesn’t mean they’re healthy! See more examples below.
Look Out For These Potential Issues
IMS Bearing – Cars Up to 2006
The M96 range of Porsche engines fitted to the 911 and Boxster up to 2005 had a catastrophic engine failure associated with the intermediate shaft bearing or IMS. At the end of the intermediate shaft connecting both ends of the timing chain mechanisms, a low cost, self-lubricated ball bearing style bearing was installed – think of it like a wheel bearing. Like wheel bearings, the IMS life is limited and it can come apart causing significant damage around the engine.
Much hype has been associated with this potential failure by people who have to gain from it, yet the anecdotal evidence shows less than 5% of the bearings fail. Porsche shipped approx. 77,000 vehicles to the USA that could have a bad IMS bearing. Even the most enthusiastic counting of IMS failures produces a total around 3500 or less than 5%. This means there are more than 73,000 vehicles that haven’t had the problem yet or have been retrofit with a newer bearing.
The M96 engine cars built up to 2000 are less susceptible to the failure than the later ones. The early cars were fitted with a dual row bearing that was more reliable then the later single row bearing fitted to the M96 engine after 2000.
Failure is expensive and usually results in engine replacement. Most diligent owners opted to preempt the failure and replace the Porsche single row bearing with an LN dual row version. Cars that have had the IMS bearing replaced have a higher value than ones that haven’t. So, replacing the bearing usually brings not only peace of mind, but a financial return when you sell the car.
If the bearing has been replaced, there will be a sticker and serial number of the bearing in the engine lid. All the bearings are serial numbered and recorded with LN Engineering. If the bearing has been replaced in a manual car, you should expect to see that the clutch was replaced at the same time.
Don’t panic if the bearing hasn’t been replaced – reduce the cost of the car in negotiation and allow about $3K for doing the work. Again, despite the hype, less than 5% fail – all you need do is find a local Independent Porsche repair shop that can retrofit the IMS bearing for you.
Overheating – cylinder liners – 986 & 987
The M96 and M97 flat 6 engines fitted in the 986 and 987 Boxster are subject to cracks in the liners of the cylinders. Each cylinder bore in the case half is lined with a one-piece sleeve or liner. The liner material is different from the surrounding case half and sometimes cracks can appear.
Results from a crack vary, but typically the most common is coolant loss with subsequent engine overheating. Sometimes, a crack in the cylinder liner can take a considerable amount of running time to fully open and cause problems. First, note the coolant level when the engine is cold. Take your time here – you want to drive the car for 30 mins.
After driving the car let it sit and idle. The front radiator fans should come on and the engine should maintain a steady temp. If the engine continues to warm and will eventually overheat, walk away.
Turn off and take a look at the coolant level – it should have risen and be falling back toward the cold level. If the level has gone down or is still at the cold level, there could be a small coolant loss through a cracked liner. The trained nose can smell coolant from the exhaust when the engine is running.
A coolant sample should be free from oil or debris. Let it sit and separate if necessary. Just don’t open the cap when the engine is hot! A Porsche repair shop can definitely help here.
Lift the car and have a listen from below while the engine is running. You might need a repair shop to do that for you. You’ll hear the M96 and M97 flat 6 engine in the Boxster make a consistent ticking sound. Much of this is the proximity of your ear to the valve train and the exhaust headers. However, there is a distinctly different sound that identifies with a particular issue that you don’t want to hear.
These engines are famed for cylinder scoring – deep gauges in the cylinder liner, usually associated with a knocking noise and eventually catastrophic engine failure. The root cause of this issue is open to discussion, however, wear in the piston rings and liners causes the piston to wobble. The wobble occurs at the bottom of the stroke and results in the piston skirt dragging against the cylinder wall thereby scoring the liner.
The sound your listening for is not a tick; it’s a rhythmic knock and usually shows up first on the passenger bank of the flat 6 engines – although, it can appear on any cylinder. The rhythmic knock is the piston changing position at the bottom of the stroke and hitting the liner. In many cases, even with the head off the engine, the scoring cannot be seen until the piston is removed – it can be way down at the bottom of the cylinder below the lowest point the rings meet the walls. Sometimes it can be seen by scoping down the spark plug tube, but the best view without disassembling the engine, comes from removing the oil pan and scoping from the inside.
The only way out of this is an engine rebuild – avoid this car.
Cam to Crank Timing Deviation – All Chassis
Timing is everything; especially in comedy and engines! The opening and closing of valves, the piston rising and falling in the cylinder and a spark are required at precise times during an engine rotation. The major moving parts are connected by chains and these ensure the relationship between those moving parts is maintained regardless of the rotational speed. The rotation is measured in degrees of a full circle. So, for example, at degree zero; piston 1 should be at the top of the cylinder and the intake and exhaust valves closed. This is known as top dead center or TDC.
Naturally over time, the components supporting those timing chains will wear – the chain itself, guide rails, tensioners etc. will all wear and cause a deviation in the precise timing angles between camshafts and crankshaft. The engine management system is measuring the angles in every rotation and within a range of angles, can adjust the timing of fuel delivery and spark to compensate for wear changes. However, extended wear can produce an angle outside of the allowed deviation range and a fault condition will be set.
The earlier Boxster experienced issues with stretching timing chains and significant wear on the timing guide rails. This caused a nasty rattle at startup and generally set faults during acceleration. Most of these issues were corrected in later cars, but during the life of an engine you should expect that these vital timing components will wear.
You need a clear picture of where the used vehicle you propose to buy is in this wear process. A competent Porsche repair shop can tell you what the deviation angle between the cam and crank is during a used car inspection. This is a simple read from a diagnostic device and a clear indicator as to the health of the engine timing.
The change in angle will affect performance and is almost certainly not something you could pick up on during a test drive of an unfamiliar car. Replacing the chains, guides and tensioners to correct this problem is not an inexpensive proposition – it is however, relatively straightforward if your budget allows.
Codes and over-revs – All Chassis
Before buying any car, it is essential to be certain when the last time the engine management fault codes were cleared and to check the status of the emission monitors. It’s not difficult for a seller to clear the faults just before you arrive to test drive. Clearing the engine faults also resets the emissions monitor system to a state of “not ready.” Emission monitor tests often occur over multiple drive cycles and after a reset, faults may not return for a significant number of miles. Again, this is easy for a competent shop to check or indeed the DIYer using a handheld scanner.
How hard has the car been driven? Taking the engine to the red line for RPM is a good thing, but going over the red line obviously can cause damage. A gear change at red line will actually cause the revs to increase slightly momentarily – nothing bad here. But, if you select the wrong gear, the engine revs to go way over the red line. This is the famous “miss-shift” that has caused many engine explosions.
Thankfully, Porsche engine management records many things and one of the most significant is known as an over-rev situation. Data is permanently stored within the ECU showing running hours and when engine events occurred. There are six levels of over-revs recorded ranging from the engine being red-lined through to what would be a potentially catastrophically high RPM event. Events in the first category suggests the car has been properly exercised, but events in the higher categories could be hiding a potential life shortening engine event.
Many Porsche owners like to go to track days. On the track, gear changes will occur right around the rpm maximum red line. These events will be recorded if they reach the lower levels of the over rev counter. Multiple recorded events in the lower over-rev categories could be a sign of how much track time the car has experienced.
We recommend you use the help of a Porsche Repair Shop to read this data and give you an assessment.
Oil Leaks – All Chassis
There are some common areas where oil leaks occur on the Boxster engine. Most are easily fixed and are part of the normal wear and tear process. One of the most common areas for an oil leak is the engine rear main seal. See our common problems page for more information. Leaking oil used to just be seen as a annoying stain on the driveway and a potential fire hazard. However, modern cars feature many electronic engine management systems that can potentially be severely damaged by oil ingress.
Oil leaks should not be a barrier to purchase, but they should be considered in terms of the purchase price – what appears to be a minor oil leak could turn into an expensive job. Again, this is where a competent shop should be able to accurately asses and relay the cost of an oil leak repair.
Air Oil Separator
An integral part of the emissions system, the Air Oil Separator (AOS) is designed to extract oil from gases in the crankcase, recycle the oil to the sump and send the gas through the combustion path to be burnt and cleaned by the catalytic converters. The AOS has caused numerous issues on Porsche engines.
As the membrane in the AOS fails, oil is sucked into the air intake. Initially this can show up as a check engine light for fuel adaptations and the oil can be deposited on the o2 sensors and cause emission faults. Of course, once it fails completely, the resultant huge clouds of white smoke are fairly obvious. At that point, it clear what needs to be done. However, replacing the aos sooner rather than later is a good precaution.
A failing aos is the likely cause of rear main seal failure as it is in other VAG cars. Crankcase gas is not extracted well enough, pressure builds in the case under acceleration and escapes out of the rear main seal causing seal failure and the resultant oil leak. A failing aos also causes oil pass into the intake and will cause the engine management to adjust fuel mixtures. The changing mixture can cause over fueling and lead to other more significant problems.
Check to see when the last replacement of the AOS was completed on the car. If there is no record, plan to replace it as a precaution.
Soft Top – All Chassis
Make sure you spend time checking the operation of the roof to ensure it goes up and down smoothly. Many of the known problems with the opening & closing mechanism should have been resolved during the previous owner’s time. Most of the top issues are usually simple and inexpensive to fix, but can be annoying if you only discover them when you want to drop the top on your first sunny day.
Porsche revised the mechanism that operates the top a few times during the life of the Boxster. Older original versions of the mechanism have parts that cannot be serviced. They need to be replaced with the entire revised system. Worth checking the history on the car to see if any work on the top has been recorded.
Importantly, look for signs of leaks from the roof into the cabin. Look behind the seats in particular. The rear roof drains can get blocked by leaves and debris over time. This results in rainwater dripping into an area of the cabin in which electronic control units are located. It is simple enough to keep the drains clear, but failing to do so can be an expensive and annoying oversight.
If the top has the plastic rear window, don’t be surprised to see this fogged. Check carefully for signs of cracks or degrading of the stitching around this window. This can be fixed relatively simply by a competent upholstery shop.
Bodywork – All Chassis
Corrosion is a rare item on the bodywork of the Porsche Boxster. Vehicles in the Midwest can exhibit some degrading of the lower panels if they have been subjected to road chemicals. However, most Porsche owners store their cars over the winter to avoid this. The bodywork of the Boxster 986 should be in perfect condition – in many cases the paint will have faded. Make friends with a good detailer who can do some paint restoration for you.
Suspension and Tires – All Chassis
The suspension on the Boxster is very solid. Naturally, over time and mileage wear can occur in plastic or rubber bushings that help to cushion the ride. Listen out for squeaks or clunks over bumps and check for leaks from the suspension struts.
Worn suspension components typically exhibit some noise and will show up as uneven tire wear. Check the tires thoroughly for smooth wear patterns and pay attention to the tire DOT date. This is the date the tires were manufactured and you’ll want to see a date that is no more than 5 years earlier. Low mileage cars in particular have this problem – the tires do not experience wear because of the lack of mileage. However, tires have a shelf life and will degrade while they sit; lots of tread doesn’t always mean a healthy tire. Despite the tread remaining, a tire that is more than 5 years old could rapidly degrade or fail when you’re driving.
On any Porsche, make sure you get under the car and take a good look at the inner shoulders of the tires – this is the most common place for extreme wear and the most likely to be missed by a walk round the exterior.
Transmission – All Chassis
The manual and automatic transmissions on the Boxster are generally highly reliable. Both should change gear smoothly and without any hesitation. The auto transmission can be scanned for faults but rarely has issues. Fluid services can be performed on both transmissions and the duration of the time interval is quite high. Look for previous indications this has been done or understand where the car is in terms of time related fluid changes.
Brakes – All Chassis
The brakes on the Boxster are generally excellent. Brake pad material does degrade over time, so again on low mileage examples check to see when the last brake service was performed. The brake fluid should be changed every few years regardless of mileage. Again, a competent shop should be able to measure the moisture content in the brake fluid and recommend the next flush interval. If in doubt, flush the fluid.
Look for new pads on old rotors. Both the pads and rotors should always be changed at the same time. Used car centers are famed for just replacing the pads on old rotors and claiming the car has new brakes. There should be a wear lip on the rotor and the size of that lip will determine how much mileage remains. Worn rotors crack or disintegrate which can be particularly unpleasant when driving!
Coolant radiators and air-conditioning condensers – All Chassis
The design of the Boxster has the placement of the coolant radiators and air-conditioning condensers low down in the front bumper. The position and open vent nature of the design leaves them not only susceptible to stone impacts, but also to corrosion due to the buildup of debris and dirt that is stuck close to the radiators.
These front ducts need to be cleaned out regularly or protected by an aftermarket screen. The front bumper has to be removed to reach the radiators and most owners never do it.
Take a flash light and look closely to see whether the front air intakes are full of rotting leaves and debris when you inspect the Boxster. Damaged or corroded coolant radiators and AC condensers cannot be repaired and must be replaced. Check the AC works and look for signs of a dry white powder stain – this is a telltale sign of a minor coolant leak.
Exhaust – 986 – 987
The exhaust on the older Boxster is now starting to show up as an issue. Cracks in the exhaust manifolds are becoming more common. Often the crack is after the collector and in the main pipe ahead of the catalytic converter. Replacement of the header section is required.
For the older Boxster, Porsche does not provide the header parts any more, so aftermarket is the only choice. The same is true for the catalytic converter sections, which over time will need to be replaced – often they degrade internally and will fall apart. This can lead to a nasty rattle or worse a blocked exhaust.
Hello or Good Buy
The older Boxster is an excellent way to enter the Porsche ownership world for easy money. Ownership allows you access to the PCA regions around the country and can turn you into an enthusiast without breaking the bank! The Boxster is very pretty and a fun car, so look past the sparkle and do your research. Uncovering a good one as they age is not always simple, but they can be tremendous fun to own for a relatively modest investment. Later versions, such as the 981, remain extremely strong cars and enjoy relatively few issues.