Malta has been my home for most of December. I’ve been travelling to and from the central Mediterranean archipelago, where Editor Furr asked me to photograph a series of cars for forthcoming 911 & Porsche World and Classic Porsche magazine features. In between my travels, I had a couple of spare days to treat my 981 Boxster S to a round of maintenance in advance of the black two-seater being retired from the road during winter. The jobs I was keen to see taken care of were an oil change for the PDK gearbox and clutch, as well as the all-important cabriolet roof drain hole inspection and clean. Truth be told, I couldn’t be sure if either of these jobs had been done in the car’s lifetime. Strictly speaking, according to Porsche’s official servicing schedule, the 981’s PDK transmission should be subjected to an oil change every twelve years or 120,000 miles, whichever comes first. My Boxster S is a late 2012 build with nowhere near that many miles on the clock, meaning the work didn’t really need addressing until next autumn. Nevertheless, I wanted it done as a precautionary measure sooner rather than later. Getting the soft top’s drain holes cleaned in order to eliminate the risk of blockage is something I’ve noted many 981 owners doing in recent months, certainly if online forum posts are to be believed. As these cars get older, if sunroof drains are left to clog up with dirt, leaves and other detritus, rogue rainwater can find its way to various electrical modules controlling functionality in the rear of the host Porsche. Audio amplifiers are prime targets, resulting in damage with the potential to cost owners thousands of pounds in repairs. I booked my car into the workshops of Knaresborough-based Porsche indie, RPM Specialist Cars (hop online and visit

 These guys have worked on both my Boxster and my Cayman GT4, as documented in previous issues of 911 & Porsche World. They certainly know their way around the 981 platform.

The first job of the day was to address the roof drainage holes. I was surprised to learn cabriolet roof drain inspection and subsequent cleaning isn’t as involved as I’d been led to believe. I’d seen online photo diaries of owners removing side skirts and wheel arch liners in order to access the drain valves, but RPM Specialist Cars technician, Andy Carling, demonstrated how this isn’t necessary. There are two valves either side of the car, just ahead of the air intakes. It took Andy around an hour to ensure water was running freely through all four channels. He confirmed two were hindered by a slight build-up of grime and small leaves, but they were nowhere near as bad as some he’s seen in recent times.

He also highlighted how garaged Boxster's (and 911 Cabriolets) don’t tend to suffer from blocked roof drainage channels anywhere near as frequently as open-top Porsches exposed to the elements year-round. Many owners will clean the valves and refit them, but the RPM Specialist Cars solution to ensuring the problem doesn’t rematerialize is to ditch the valves altogether. They serve little purpose and can cause large repair bills. Whether you’re in possession of a 981, 987 or even a 986 Boxster, make sure you ask RPM Specialist Cars or your local independent Porsche garage to inspect the car’s roof drainage system.

For the sake of less than an hour’s labour, there’s no reason to risk the onset of avoidable damage.

Next up was the PDK gearbox and clutch oil change. Some of you may recall a fleet update documenting the same work being applied to my GT4 at RPM Specialist Cars a few months ago. As was the case then, I decided the Boxster should be treated to Motul Gear 300 LS oil, which I have been very impressed with. Independent tests have shown this particular lubricant to significantly reduce wear in Porsche race car gearboxes. I’ve certainly noticed reduced transmission whine and more satisfying shifting in my GT4, hence not hesitating to use the same product for the Boxster. It’s a fully synthetic 5w-90 lubricant designed specifically for high-performance transmissions and meets Porsche’s recommended GL-5 standards.

For the PDK unit’s twin ‘wet’ clutches, I opted for Motul Multi Double Clutch Transmission Fluid (DCTF), which also meets OEM standards. As before, I ordered both products from the website of Octaneologists, one of Motul’s leading UK stockists. It’s worth noting how RPM Specialist Cars is also very impressed with these products, hence the company having all grades of Motul oil in stock and ready to use. In total, the Boxster took three litres of gearbox oil and close to 5.3 litres of clutch oil. PDK transmission fluid changes are definitely more involved than changing the oil on a manual 981 gearbox — once the dual clutch oil is replaced, it has to be ‘blended out’ and taken to a specific operating temperature before the fluid level can be accurately read. A clutch recalibration procedure using special diagnostic tools also needs to take place. During this process, the transmission can be heard finding its biting points.

After Andy confirmed he was happy with the recalibration, he took the car for a test drive and subsequently told me the gearbox was working good as new. I have to say, dealing with RPM Specialist Cars is always a pleasure. Nothing is ever too much trouble and the team is always happy to not only talk through the work being done, but also to explain the benefits. Put it this way, I always come away with fresh knowledge about how my cars work, for which I’m very grateful to Andy and his colleagues. Unfortunately, the drive home was characterised by terrible weather, which prevented me from pushing the transmission hard, but on first impressions, shifting is silky smooth. I’ll be sure to provide a detailed road test report when the car returns to the road in spring. - Chris Wallbank

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Wednesday 17 January — Nathan Forster-Green

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