Work has begun in earnest on our Porsche 944 S2 project car, and the first focus is under the hood. The S2 variant of the 944 has a 3.0L, 16-valve inline-four engine (essentially half of the Porsche 928 S4's V-8, in design) and is capable of making solid power—208 hp and 207 lb-ft of torque to be exact. However, to keep making this power reliably, it's important that maintenance is up to date.
When we bought the S2, the car had a cracked cylinder head that required replacement. The cause of the damage was never determined with any certainty, but it's suspected that a previous shop improperly torqued the head during a head gasket change. While at local Porsche specialist European Motorsports, it also received its fair share of preventative maintenance. At the top of the list were fresh timing and balance shaft belts. Porsche recommends changing these two belts every 45,000 miles, although common Internet knowledge recommends changes on roughly 30,000-mile intervals. At the same time, there are plenty of "while we're in there" items to look at. The rollers on which the belts move should be checked for smooth play; if they bind, they can lead to belt failure. The water pump should also be inspected because if it needs to be replaced down the road, the belts will need to come off yet again. Oh, and it's worth noting that the 944 S2 has an "interference" engine. That is, if the timing belt fails, valves are likely to meet pistons. For that reason alone, it's worth keeping on top of belt services.
While our car came to us with service history from new that showed it had been well maintained, we opted to give ourselves peace of mind by replacing virtually all of the belt-associated items while the car was under the knife. New belts and pulleys (or "rollers" as they're sometimes called) aren't terribly costly on their own, but a factory water pump from Porsche runs about $600. A little research and we opted for a rebuilt unit from Zims Autotechnik for about $120 plus a $125 refundable core charge. If you have a 3.0L car, be sure to specify that when ordering a new pump—the correct one is higher flowing than the more common 2.5L version. We also replaced the timing belt tensioner for added precaution.
The 16-valve cars, like ours, use a chain to drive the twin camshafts. This chain also has a tensioner, which while generally reliable, has an Achilles' heel. The tensioner's plastic guides or "pads" that the chain runs along often grow brittle with age. When they break, they take the chain out of tension with devastating consequences. The entire tensioner is available brand-new with pads for somewhere south of $400, but we opted to just replace the pads—again, from Zim's—for about $130. The valve cover gasket and front engine seals were replaced with new ones as well.
With all that work completed, we brought the car home and found we had a nice running and driving example of a classic front-engine Porsche. As with any older car, there were still other issues to address, however. The most immediate was a power steering fluid leak that the last mechanic had alerted us to. The leak originated from the hoses that attach to the base of the power steering fluid reservoir, and simply re-tightening their hose clamps didn't fix the leak. The lines themselves looked like they had seen better days and are located very close to the hot exhaust manifold, so we opted to simply replace them. The first hose runs from the reservoir to the power steering pump—also known as the "exit" line. It was replaced with the OEM part from Circle Porsche in Long Beach, California. The second "entry" line is a little trickier. It runs from the power steering cooler in the nose of the car, returning the cooled fluid to the reservoir. Unfortunately, Porsche doesn't sell just the rubber line—it wants to sell you the whole cooler assembly, hose attached. Not only is it expensive, but it's also a lot more work to replace the assembly than just the rubber line.
We turned to ArnnWorx, a U.S.-based, Porsche-specific parts vendor that specializes in offering aftermarket parts and tools of high quality, but lower cost than OEM. Bruce Arnn is the owner and he makes a replacement rubber line that connects to the existing power steering cooler. The hose is complex, as it requires a larger fitting at one end than the other. Bruce accomplishes this by joining two hoses together and protecting the junction from engine heat with an insulating sleeve. ArnnWorx also supplies the Oetiker crimp-type fittings to secure the new lines (you'll need an Oetiker tool to crimp the fittings—about $15). It took us a couple hours to cut off the old hose's metal pressure fitting and replace it with the ArnnWorks line. To get access, it's necessary to remove the car's nose panel first by removing the myriad screws that fasten it to the car. Even then, workspace is tight, but be patient as you work the fresh line onto the fittings at the reservoir and fluid cooler. A little heat from a hair dryer can help soften up the rubber hose to make installation a little easier. Before you start any of this yourself, be sure to drain as much fluid as you can from the reservoir using a bulb-type device (the turkey baster in your kitchen will work—just don't reuse it after!). This minimizes the amount of fluid draining from the lines during disassembly. When refilling the reservoir afterward, fill slowly and check the level often. Work the steering wheel from side to side to ensure fluid is filling all the lines and leave the reservoir cap off to allow air to escape.
It's nice not having drops of red power steering fluid on the floor of the garage after each drive, but we've still more to tackle on this 944 S2. Next up: more preventative maintenance before we dive into the fun stuff.