Where exactly is check valve #16? Mine's also leaking badly. Pressure test shows air just dumping into the driver's side intake hose before the turbo. I tried tracing it up and it looks like it goes to a tee junction just above the TB over to the driver's side a little. It's to cramped to reach in there and touch any of them but there's about 3 items there that all look like the check valve. I don't know which one I'm after?

 

you're in exactly the right spot. this'll clear it up for ya

 

I ordered a replacement check valve last night but it'll be a week or so before it's here.

So what all do you pull out to gain access? Still not sure I've identified the right item in the engine bay. It looks like I may have to pull the air box, intake plenum and even the throttle body to reach up behind it to the left to replace it. Does that sound right?

 

Yes. If I remember it all correctly. once you've got to the TB and plenum ( or behind it i suppose ? ) all is revealed. It is right there left?? of plenum and yeah all the intake stuffs needs removal. But its been a couple years and its said memory is the first thing to go.

Pull out airbox y pipe and TB I think you'll see where it is. GL w it but you know what you're doing. At least now ya know what that Lil sucker looks like.

 

OK it sounds like we're talking about the same part. I won't take it apart till I get the replacement valve so I can at least drive the car in the mean time. I can see now why people look for stronger replacement part that won't fail.

I often wish the rear seats doubled as an engine bay cover. Pull them out and reveal the rest of the engine we can't access

 

ya, gotta be the same. yeah, they stuff a whole lot back there!

i am reminded of david crosby of csn&y years ago had a vw bus with what was it? a 1500? porsche motor? no trouble reaching in there! but this is madness. all i can reach is the paper filter oil filter and the maf LOL

man, do i ramble.. sorry. you've got it. it'll be night vs day once you swap it out. curious to see if your boost levels are noticeably improved. they'd have to be, i would think!? keep us posted. i am certain a lotta folks have cracked check valves and dont even know.

 

I see a max of 1.0 bar WOT in 3rd and 4th. Everyone says I should be seeing more like 1.2 bar with my setup so that prompted me to start investigating.

 

absent issues, I'm guessing that would depend upon your tune? but you are running hybrid turbos; 24's? so i'd be very surprised if you did not have a 1.2 tune. i also have hybrids and am tuned for 1.2 and see 1.3 daily. if i lose boost i go ape sh*t until i figure it out. cant have that! lol

add: a cracked #16 is JUST the kinda thing to have you lose .2. you're on it! GL.

 

I just went through changing this valve. Assuming things go smoothly, it's not hard. However... the rubber hose that connects the valve to the Plenum was basically shrink wrapped around the valve and the nipple of the plenum. End result was a broken plenum. Even out of the car I can't separate the hose from the valve. The good news is it meant I could justify the IDP plenum lol.

What I will say is that you should be careful. If the hose doesn't pull off the valve easily you might be in the same boat.

 

Thanks for the heads up. In hind sight could you have taken a razor blade and split the shrink wrapped tube and to separate the check valve from the plenum and then replaced it with a regular piece of vacuum/boost tubing.

 

Yup. Likely would have had to remove the plenum but to be honest I didn't even consider it a possibility that it would be break. Couldn't figure out for the life of me why it wouldn't let go... until it did.

 

Yeah it happens. I'll be careful and watch for that. Thanks!

 

before starting a new thread-It seems I'm having somewhat the same issue. I boost pressure test at lower intercooler hoses and 5-6 psi is held before air after 5-8 seconds starts leaking inside air inlet hose. It is not an external boost leak(torn hose or intercooler pipe) but an internal where the air is pushing back into the inlet hose. I noticed this when removing airbox and sticking a garden hose inside the inlet and hearing the air. Normal? Any suggestions? Could it be the dreaded 16 check valve?

 

The way I isolated check valve #16 was to look a few inches in front of the driver's side turbo on the inlet line. There's a hard tube that connects to it. Press in the clip and disconnect it. Pressure test and if air is blowing out of that hard line tube you disconnected your check valve is shot.

 

^ that's really good info. Also once you are testing you should hear it almost "whistle" though perhaps mine was trying to help me. Took me awhile for..me? ..us, to figure it out.