I pulled my supercharger out to replace it (and all that entails), and after I was done, I found a small r-ring on the floor that I didn't see come out. It's a little strange in that it doesn't appear to be metric, but appears to be 3/8" ID and 1/2" OD, measured using calipers. I'm pretty sure this o-ring hit the floor as I pulled the s/c itself, but dang if I can figure out where it came from. My only theory was that it covers the little protrusion that fits into the pulley-side bolt at the top (the side-by-side bolts where one protrudes and the other is flat). But I haven't seen any reference to that anywhere. Any ideas?

 

Water pump o-ring?

 

Thanks for the reply. But it's not the water pump o-ring. This is a little pinky-sized thing. It's closer to the dipstick o-ring size than anything else. I've looked at all the parts diagrams, too, and don't see it. I was just checking here to see if I'd missed something. I suspect it's just an extra part dropped on top of the engine a long time ago. It would explain why it doesn't seem to be metric, at least.

 

Possibly an injector o-ring?

 

Sounds like the o-ring that fits inside the little red vacuum line retainer clip. It's roughly the same size as the blue Viton o-rings for the TMAP sensor, correct? Also, nothing on the blower itself is metric as it's mfg'd by Eaton, a US company.

 

My guess:

Is it from the oil dipstick tube that’s usually pulled out when the s/c is removed?

 

hmm. Could be. I looked at the new s/c and didn’t see a rubber ring on that one, but if it’s on the inside, and came off when I pulled that vacuum line, it could be it. I’m not taking the new one apart to find out. In any case, it doesn’t sound like I’m missing anything huge and am going to button this up today and put it back on the road (or come back here with new questions...)

And it’s definitelt not the water pump o-ring, which is a larger ring, and still attached. Thanks, everyone.