Anyone know the proper size for the o-ring on these. I bought them off crate engine again but this time they didn't send me the black ones.

 

Found this: "You need a Viton size 202 o ring. I suggest Mcmaster part 5577K202."

This, too, lol:

Hooked up ds33gt too. I'm down to 40 or so of these things They are milspec buna-n, aka nitrile. I ordered mine from Mcmaster in a 50 count bag, but they were really repackaged from oringsusa. $13 from Mcmaster for a 50 count bag, or 22 cents each plus shipping from oringsusa.

oringsUSA

http://www.mcmaster.com/nav/enter.asp?partnum=5018T239 (price has gone up since I bought them)

I also tried a few Viton and Fluorosilicone, and neither of those options work. Too stiff. You will break the GMS sensor trying to get them on.

 

Yes, I posted that info some time back.

It appears CED has different orings now, but size 202 is correct. Material is critical. Stick with the buna-n ones from McMaster Carr that I linked.

p.s. Use dielectric grease or some other silicone grease to slip them on. I would pass on engine oil, having had contamination problems with that. Go lightly with the lube!

 

Not be a dick but im pretty sure CED tells you the map sensors dont come with o rings.

 

Meh do what I did when mine tore, left the torn one in and put silicon around it. Holds better than any oring. Just don't drive till its dry.

 

I've only had my Cobalt SS/TC for a week, and you can tell I'm still a kitten by my join date/post count. Based on observations throughout multiple threads, it looks like Wangspeed knows his stuff.

 

I think it's best that they do not come with orings. There are 2 sizes. One for HHR, and another for Cobalt. There have been so many mix ups with this. I've fixed multiple cars in this area alone that have had the wrong o-ring.

Bill from GM kindly provided the info that it was -202. It's buried in some thread on here. Sadly, I've not seen anyone from GM post, aside from customer service.

Don't use silicone. That is a phenomenally bad idea. The sensors are extremely sensitive to oil and water, and need to be cleaned off with MAF cleaner once in a while. When? Usually when you start getting BPV flutter.

Thanks prevsrt4owner.

 

Thanks I have lots of 202's in stock. By the way I'm a industrial parts supplier so I have lots of these types of things in stock haha. Thanks for your help I just didn't want to go home and take the old rings off and then have to bring them in tomorrow for a match-up.

 

Too bad you live in another country (barely). I do, however, approve of the girls up there.

 

This sounds like something I need like yesterday! If I'm gonna replace my intercooler I might as well clean my sensors and replace the o-ring, have had the flutter for a while.

 

I probably wouldn't have used Nitrile. I looked at the different O-ring materials and fluorosilicone is probably the best route to go. They all have similar durometer ratings (A70-A75) so one being more "rigid" than the other shouldn't be a problem, just use plenty of lube. The fluorosilicone is also rated to a colder temperature that makes me feel more comfortable. The Buna-N/Nitrile and Viton O-rings don't seem to be rated as low as what the rest of the engine is rated for, but I could be wrong.

I avoided sliding the O-rings over the 3-bar MAP sensors, there is part of the flute that is sharp and could tear into the O-rings if you forced them down. I wrapped the flutes with clear scotch tape so the o-rings would slide right down.