Hi all, so I recently replaced the starter in my 2010 CS, then degreased and cleaned the engine as it was much grimier then I expected. Unfortunately, I unknowingly left an oil vent line that connects to the oil fill tube just aft of the starter unplugged. This caused a idling condition forcing me to remove the plenum a second time. During the removal I noticed some oil in there, but didn't think twice about it as there was some in there prior as well. Anyway, after fixing the disconnected tube and putting everything back together, the car is running great. But now I've noticed an oil leak directly over the oil cooler, or whatever that is. I only noticed it because the engine was just cleaned. Upon inspection, the oil is dripping from the drivers side plenum clamp. I thought maybe leaving that line disconnected somehow caused some oil to get sucked up there at first, but even after a good 2 hours of driving, I'm still seeing dripping there. I googled this issue but couldn't really find anything to help me sort out why. AOS was my first thought, but I'm not getting even the slightest hint of smoke on startup, though maybe that's not the best way to test AOS? Any thoughts or ideas what would cause this? The car feels great and the oil level seems pretty stable as I checked it constantly while out running errands with it. Not really sure where to go from here.

 

A quick/easy way to check the AOS is to remove the oil fill cap while the car is running, if the cap wants to be "sucked back down" onto the fill neck, then you have a sign of excessively high crankcase vacuum.

Here is a bit more of a scientific approach.

 

Thanks. Will test out the suction tomorrow and give that video a watch tonight. Guessing there's not a cheap Amazon tester everyone is using at this point, but I'll dig into the video and see what he says.

 

the guy in that video has a link for one that is $50....with how my car act, I don't think its worth the investment, I've got a lot of years without a vacuum tester.....LOL

 

Do not use that AOS test on a 987.2. The later 9A1 engine has much higher crankcase vacuum than the 987.1 so you'll think you have a bad AOS when you don't. The 987.2 AOS is also much less likely to fail.

I had the same issue, see my post #6 in this thread on stuff to check. Probably you just have a bit too much oil in the car and didn't tighten the clamps enough, there's a torque spec in the service manual.

https://rennlist.com/forums/987-foru...of-engine.html

 

Thanks for that info. I did fill the oil to the top line recently. Seemed like a smart thing at the time. I'll double check the level and search for that torque spec on those clamp bolts. Would be nice if it was a simple fix like this.

 

My 987.2 had the exact same oil look on top of cooler mine was actually dripping down, independent said he tightened up some claps no issues since, its been a couple of years now.

 

Thanks for the feedback, good point, I missed that test being specific to the 987.1 cars; I may need to get manometer to test my car, at times get excessive smoke at startup (car also has over 75k miles)

 

If I'm looking at the right place it's 3.5 ft-lb, but you should probably verify that

 

Thanks. I'll double check, but if that's correct I'm going to need to buy a new torque wrench capable of numbers that low. Looks like I can pick up a Lexivon from Amazon for about $30. Just need to convert to in-lb....about 42 in-lb I believe.

 

I was having smoke at startup on my Boxster (82k miles). I replaced the AOS along with the oil vent lines when I was doing maintenance over the winter. No smoke at startup now. The AOS was the cheap part, the vent lines were far more expensive to replace but the original lines were extremely brittle and easy to break. They really had to be replaced to do the job.

 

Thanks for the heads up on this. Just torqued to 42 in-lb (3.5 ft-lb), and I was way under spec on those bolts. Was worried about cracking the plenum/runners or stripping the clamp just going by feel, but pretty confident this should stop the leak. Cheap enough tool to keep in the tool box for future work as well.

 

Happy to help. I'd suggest keeping it one bar below full on the oil as well: you'll very likely get less in the plenum and less oil usage overall.