Some time ago, actually before the oil change, the car had started to make an odd noise when warm. One person said it sounded like an exhaust leak, but that didn't seem to be it. The pattern would have made it from a single cylinder rather than from further down the exhaust, and all of those joints were tight and not leaking. So we had a mechanic look and listen. The mechanic said the sound was coming from the vacuum pump. The pump was probably failing. It wasn't a major concern, though. This car has a vacuum pump because it does not always create enough vacuum to drive everything for the motor plus the brake boost and the exhaust flaps. It prioritizes the motor's needs, so when the vacuum pump fails, our exhaust flaps won't work anymore and the brakes will feel a bit different. The brakes will lose part of their boost, but not all of it. That symptom list is not particularly concerning, so the mechanic recommended waiting until it actually failed to replace it. We double-checked with Sharkwerks that all of this was sane (since they made so many changes to the car), and James agreed it seemed like a reasonable course. So we carried on.
At our next track day... the pump failed. The brakes became just a bit softer (but not by much). I didn't notice the exhaust. The car ran fine the rest of the day, though. We then brought the car home and tried to order the part. There's a sticker on the old vacuum pump that has the part number, but in 9 years, it's faded:
We did our best to guess at the part number, and sent the image to the place we ordered the part as well. They checked their catalog, and no part number that seemed to match any interpretation of what's pictured was in the catalog. However, there was a vacuum pump listed for a 2007 GT3.
This website seems to pull from the same catalog, and you can see the vacuum pump listed as 997.105.016.90. Sometimes a change is made to a part, and the part number updated, but the part will still work. So the part number that was sent is 997.105.016.90. This also suggests that faded part number is 997.105.016.71. Google had no results when I searched for that number, though (presumably it'll index this at some point and this post will become the result). And, of course, that 71 (particularly the 1) is a best guess based on a terribly faded number - maybe it's something else that is hiding in the catalog somewhere.
There was a mix-up that delayed shipping, etc., and we didn't end up getting the part until Friday. Yesterday we tried to install it. We got the old pump off and discovered... the parts are different.
Well that's just great. Note the sticker on the new part we have says 997.105.016.90 AS01 (barely visible in that image). I don't know if that AS01 is relevant or not, but... after poking around at the online version of the catalog... I'm just confused. There is no 997.2 (or 2010/2011) GT3 listed there. There's two "oil supply return line" categories with different parts in them, but only one of them actually has a vacuum pump and neither has a 997.105.016.71 part. There is a "Vacuum line tandem pump" in the other "oil supply return line" part of the catalog, but the price difference suggests it's rather different.
We emailed the parts supplier to let them know, and we emailed the Sharkwerks folks to see if they had any insight. James replied that the new part, the .90, is for the 997.2, saying, "That engine has no scavenge pump driven by the cam and has variable exhaust cams hence the different drive system." He also offered to find the correct part number on Monday. They have a few different databases and systems to search for part numbers (we watched them dig through them when looking for the power steering line), so hopefully they have one with the correct part number. This makes me happy - both that they're so helpful, and that James knows off the top of his head exactly what's going on, just from a few photos.
This delay is disappointing, though, as it's unlikely we'll be able to get the correct vacuum pump in hand before next weekend, which we'll be spending at TWS.
Full gallery from the installation attempt.
