How to Prevent Porsche Bore Scoring

Car engines contain a large number of components made from aluminum. In your modern watercooled Porsche engine, this includes the pistons and cylinders. Aluminum is lightweight and versatile, but it has its limitations. For decades, Porsche used a durable Nikasil plating for the wear surface of the aluminum cylinders that is not susceptible to cylinder bore scoring. For Boxster, Cayman, and 911 engines, Porsche chose to use hypereutectic Lokasil and Alusil engine blocks instead that have raw, uncoated aluminum bores. For this reason, over time, your Porsche may experience bore scoring or cylinder bore scoring.

What is Porsche Bore Scoring?

Porsche cylinder bore scoring occurs in engines with Lokasil and Alusil engine blocks when there is a breakdown of the Aluminum-Silicon (Al-Si) cylinder system. When the required iron-clad piston coating fails or there are insufficient exposed silicon particles remaining on the face of the aluminum cylinder bore to support oil film formation, there will be accelerated wear on the pistons, rings, and the cylinder walls. As the pistons and rings move up and down the cylinder, wear debris will be dragged through the bore, causing cylinder bore scoring.

Which models are most affected?

Certain Porsche models are more susceptible than others to Porsche cylinder bore scoring. Porsche 911 996 and 997 cylinder bore scoring in 3.6 and 3.8 liter M96.03, M96.05, and M97.01 engines and Porsche Cayman cylinder bore scoring in 3.4 M97.21 engines are most common; below are all the models with M96 or M97 engines that can experience this issue:

• Porsche 996 bore scoring
• Porsche 997 bore scoring
• Porsche 911 bore scoring
• Porsche 987 bore scoring
• Porsche Cayman bore scoring
• Porsche Boxster bore scoring (3.4 M97.22 engine only)

Consider that for an engine that has traveled 60,000 miles, each piston has gone up and down over 300 million times on average. If the required preventative maintenance as outlined below has not been carried out, serious damage and potentially engine failure can occur. The reason that taking the steps to prevent Porsche bore scoring is so important is that it can have extremely negative impacts on your car’s performance and engine longevity. As the scoring worsens, the cylinders will lose their ring seal, and harmful contaminants will enter your oil as it bypasses the piston rings. Those contaminants can then be spread throughout to all the lubricated components in your Porsche’s engine, eventually leading to catastrophic damage in the worst case scenario. It’s far cheaper to take these steps to prevent Porsche cylinder bore scoring through preventative maintenance than wait to have a failure and have to rebuild or replace your Porsche engine.

Are there any other vehicles that can suffer from bore scoring?

Any engine with a hypereutectic aluminum engine block with uncoated aluminum bores, like those enginewith Alusil Engine blocks, can suffer from cylinder bore scoring.

• Porsche Cayenne bore scoring
• Porsche Panamera bore scoring
• Porsche Macan bore scoring
• Mercedes-Benz bore scoring
• BMW bore scoring
• VW/Audi bore scoring

Engines with aluminum engine blocks require pistons with iron clad piston skirts, typically plated or coated, to prevent aluminum on aluminum contact. If these coatings, fail, bore scoring will occur.

These blocks requires a chemical or mechanical exposure process that removes aluminum from the surface of the cylinder bore and exposes the silicon particles that make the whole thing work. The tipping point for when this fails is when 40% or more of the exposed silicon particles are damaged. The required tribofilm is then compromised, leading to increased wear, including scoring.

Although not anywhere as common as the bore scoring issues that plague the M96/M97 engine, the above vehicles are known to and have been documented as suffering from cylinder bore scoring. Although these engines and vehicles differ greatly, following the same preventative maintenance can help reduce the likelihood of engine failures from cylinder bore scoring.
 

Porsche Bore Scoring Preventative Maintenance

The question we are often asked is how can you prevent bore scoring from happening to your Porsche Boxster, Cayman, or 911 engine? We’ve put together a few steps you can take to extend the life of your engine and to prevent or reduce the likelihood of Porsche cylinder bore scoring.

• Borescope your cylinders – It is an excellent idea to know the condition of the cylinder bores. Bore scoping your cylinders for Porsche bore scoring is critical, especially important if you are in the market for buying a new (to you) Porsche.Be sure to scope the cylinders from the spark plug and also through the sump (on models where this is possible).
• Check your fuel trim and test for vacuum leaks – A Porsche technician with the proper diagnostic tools should be able to check fuel trim values to ensure they are within specification. A badmass air flow sensor oroxygen sensors can also cause over-fueling that will wash down cylinders and lead to bore scoring, so these components, along with theoil fill tube and AOS (and associated vent lines), also need to be replaced as part of preventative maintenance to ensure your engine is running correctly. Vacuum leaks can also cause your engine to run rich, so having the engine smoke tested to check for leaks is highly recommended. The Durametric Porsche Diagnostic Tool can be used to check fuel trims as well as mass airflow and oxygen sensor values.
• Perform a manometer test – A healthy M96 or M97 engine should have a manometer reading 4.0-6.0″ of H2O. Low manometer readings may indicate worn piston rings or poor ring seal. High manometer readings may indicate a faulty AOS. The CR Tools Porsche Crankcase AOS Vacuum Measurement Manometer Tool allows you to easily perform a manometer test on your Porsche engine.
• Purchase high quality gasoline – Choose Top Tier or ethanol free premium fuel for your Porsche to keep your fuel injectors as clean as possible. Dirty injectors can hurt cylinder and piston lubrication, leading to excessive wear.
• Maintain your fuel injectors – Use a bottle of Driven Injector Defender every other fill-up. We recommend replacing your fuel injectors every 75 thousand miles to eliminate the chance of leaky injectors washing down your cylinders that can lead to bore scoring. Having your original injectors cleaned rather than replacing with new ones is not recommended.If your injectors are leaking, replacement is the only fix.
• Install a low temperature thermostat – A low temperature thermostat opens earlier and stays open where the factory thermostat can cycle open and closed during normal operation, causing the coolant to bypass the radiators and creating hot spots in the engine.
• Start out slowly until warm – Never let your Porsche engine idle to warm it up as the rich mixture during cold start can wash down cylinder bores just like a bad injector. It’s important to start driving immediately but keep engine rpm below 3000 rpm and avoid running the engine at wide open throttle until the engine is at full operating temperature.
• Change oil at the recommended intervals – It’s important to change your car’s engine oil every 6 months or 5,000 miles using a recommended motor oil like Driven DT40 or Driven DI40, as these oils are formulated with increased levels of Moly additives that most oils do not have, which in turn helps to protect the cylinder walls. If you track your car, drive short distances, or operate the engine in cold climates, more frequent oil changes may be necessary. Doing so will help the oil remain free of contaminants that could lead to Porsche cylinder bore scoring.
• Don’t neglect your filters – Be sure to change your engine oil filter every time you change your Porsche’s oil with a quality oil filter. Consider LN Engineering’s Spin-on Oil Filter adapter, adding FilterMag oil filter magnet, and one of our Porsche magnetic engine oil drain plugs. Don’t forget to replace your air and fuel filters as recommended by Porsche, only using Genuine, OEM filters, or filters recommended by LN Engineering.
• SPEEDiagnostix oil analysis – Conduct used oil analysis at every oil change to monitor for levels of abnormal wear levels or contamination in your engine oil. Even if you do not have any symptoms, the data you receive from the analysis could tell you if bore scoring is already occurring, or if there are contaminants in your oil that may accelerate the process such as excessive fuel dilution which may point to other problems with your engine that need immediate attention.

What if you already have Porsche bore scoring?

If you already have Porsche 996 bore scoring, Porsche 997 bore scoring, Porsche 911 bore scoring, Porsche 987 bore scoring, Porsche Boxster bore scoring, or Porsche Cayman bore scoring, then we can help. Same goes for any other vehicles that use Alusil or similar hypereutectic aluminum engine blocks.

Your first step is to correct any lingering uses contributing to cylinder bore scoring, all of which are outlined above.

Second step is to immediately switch to a thicker oil. For Porsche models with bore scoring, Driven DT50 or Driven DI50 is ideal. The increased viscosity should slow down the progression of bore scoring and extend the lie of your engine, allowing you to start planning and saving up for an engine rebuild. We’ve seen instances of engines with bore scoring going up to 10,000 miles after diagnosis, assuming these steps are followed.

Don’t believe us? Counterintuitively, the advances in modern engine oil technology are detrimental to bore scoring prevention, with most formulations optimized for emissions system preservation and supporting fuel efficiency. Case in point—General Motors’ current suggested “fix” for the problematic 6.2-liter L87 V-8 is to use 0W-40 rather than the prior 0W-20. So if your engine uses a 0w20 or 0w30, you might consider using a thicker oil regardless!

Contact our team to help avoid Porsche cylinder bore scoring today!

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