From its inception, the Porsche Boxster’s engine was meant to deliver dependable performance — and every generation has delivered that in spades.
In the early 1990s, Porsche was struggling financially. With dwindling auto sales all over the world and expensive manufacturing costs, Porsche needed to come up with a new project to balance the books, which is where the Boxster comes in.
Released in 1996, the Porsche Boxster has gone through four generations in its 25 years of life. Over that time, the power unit has not changed much.
Traditionally, Porsche sports cars have been driven by horizontally opposed engines commonly known as “Flat” or boxer engines. What makes these motors different is the pistons move side to side rather than up and down like standard engines. This allows the cylinder heads to be mounted on the sides instead of the top, creating a very compact power unit.
In this article, we will cover what makes each generation of the Boxster engine different, and we’ll address some common problems you may encounter.
Porsche Boxster 986 (1996-2004)
The first-generation Porsche Boxster is referred to as the 986, and it is powered by a lower displacement version of the M96 Carrera engine. A new power unit brought big changes to Porsche engines, mainly by being water-cooled instead of the traditional air cooling.
Boxsters built in the mid-Nineties have a 2.5L flat-six engine producing 201hp and 196 lb.-ft. of torque. In the year 2000, the standard Boxster received a slight displacement bump to 2.7L, and the 3.2L S model was introduced as a new trim level with a brag-worthy 250hp and better brakes.
If you own or are thinking of purchasing a 986, here are some common issues you might encounter.
- Oil separator: The oil separator is a black plastic box located on top of the engine and is part of the crankcase ventilation system. It is used to trap oil as it travels through the vacuum system. With age, the separator becomes less efficient, causing oil to be drawn into the engine and being burnt. Common symptoms of failure are excessive smoking on startup or constantly while running.
- IMS bearing: A rare, yet overly publicized problem is the intermediate shaft bearing. Due to the design of the M96, the camshafts are not driven directly by the crank like normal engines. The crankshaft drives the IMS with a chain which in turn drives four other chains that drive the cams. The flaw is that the bearing is not lubricated by engine oil it has internal grease and needs service around 60,000 miles. Neglect of this crucial maintenance causes the bearing to overheat resulting in catastrophic failure.
- Immobilizer: If you have ever owned a convertible you know that a car without a solid roof is going to leak. Normally this is just the cost of doing drop-top business but can be a big problem in this Boxster. The engine immobilizer is located under the driver seat and in severe weather the floorboard fills up with water frying the module. It takes very little actual water to cause this and renders the car immobile. This is such a widespread issue a few aftermarket companies make waterproof boxes for the module to remedy it.
Porsche Boxster/Cayman 987 (2005-2012)
The 987 generation brought subtle styling changes like updated headlamps, bigger wheels, a fresh interior, and a new hatchback body style called the Cayman. With a new model came a new engine: the M97. The base Boxster and Cayman kept the 2.7L displacement but now producing 236hp, while the S models 3.2L jumped to 276hp. Among other changes, Porsche addressed the IMS issue.
Now the intermediate shaft bearing was much more robust and required the engine case to be split in half for service. This overhaul procedure is almost never necessary with the new design, but they didn’t catch everything so here are a couple of common problems.
- Rear main seal: The rear main seal is a flat rubber gasket that seals the flywheel side of the crankshaft. Over time, the rubber deteriorates allowing oil from the crankcase to leak out. This problem can easily be spotted by oil leaking from between the engine and transmission. If your car has this issue it is a good time to also check the condition of your clutch and IMS cover seal because the transmission needs to be removed to inspect the seal.
- Variable valve timing solenoid: A new addition along with a stronger IMS came variable camshaft timing. This allows the engine to change the intake and exhaust cam profile, depending on the load. The advantage to this is, by using oil pressure regulating solenoids, the engine control module, or ECM can adjust the timing for better performance or fuel economy. These solenoids are a known weak point in the system and can cause symptoms like a check engine light or it can even lead to the vehicle going into limp mode.
Porsche Boxster/Cayman 981 (2012-2016)
The introduction of the 981 in 2012 was a major update to the Boxster platform. The shift to the more modern 991 Carrera styling really did the Boxster a favor by making the car lower and wider. The standard cars kept the M97 engine but with a little more power the 2.7L flat-six power output rose to 260hp, the S model gained more displacement to 3.2L and 310hp.
In 2014, the new Cayman was released and the S model received the direct-injected MA1 engine. The new delivery system allows fuel to be sprayed directly into the combustion chamber giving way to better fuel economy and more power.
More often than not, big changes in the automotive industry bring problems, and here is one you should look out for on the third-generation Porsche Boxster and Cayman.
- Carbon build-up: Direct fuel injection has become the new normal in the automotive industry due to its clear superiority in emissions, fuel economy, and performance over port injection. How it works is, instead of fuel being sprayed into the intake manifold, it is delivered directly into the combustion chamber. This helps the fuel to burn much more efficiently, making more energy in the fuel available. Joining this with precise ignition timing gives way to more horsepower, torque, and improves miles per gallon.
The main drawback to this new technology is with no fuel passing over the back of the valves and carbon slowly builds up on the back of the intake valves.
Over time, as the layer of burnt fuel vapor gets thicker, the valves can no longer seal properly causing rough running, check engine lights, misfires, and ticking sounds from the engine.
To remedy the issue, the process involves removing the intake manifold and using a walnut blaster to break the carbon up, then vacuuming it out. Each cylinder is cleaned individually by turning the crank so all the valves are closed on that particular cylinder. It is done this way to ensure no debris falls into the combustion chamber damaging the engine.
In late 2016, a new model was released that Porsche named the 718 losing the Boxster nameplate. Even though the new model has more power than the old one, it was met with cries of heresy from Porsche fans. The traditional six-cylinder was replaced with a turbocharged flat-four due to ever-tightening emissions regulations.
The lifecycle of the new 2.0L DDPA and 2.5L DDNC engines seem to have been short-lived as Porsche has announced the return of the flat-six after receiving so many complaints from customers.
Porsche has always been known as one of the most reliable brands to ever come out of Germany. By any metric you judge the various power units available in Porsche Boxsters, they’re all reliable. From the car’s inception, it was meant to deliver dependable performance, and every generation has delivered that in spades.
Photos: Porsche
