Macster

What I've been told can happen with the Turbo hoses is when the hose is slipped over its connection a piece of hose, a flap of rubber, gets folded back. The hose fits securely after tightening the clamp but this folded piece of hose is a leak point when the intake is under pressure.

If is important that one check for any flaps of rubber hose at the end/edge and if found replace the hose or very carefully when installing it be sure the flap doesn't get folded back.

SEA996TT

Thanks, good to double check. The only remaining smoke leaks come from behind the intake, left side up front somewhere. It is not a lot, but must be enough to not pressurize at all.

What is up there? What does the intake connect to after the airbox?

rmc1148

A mirror may help you see behind the box for leak, I'm sure you will get some good advice here as leaks are common.

"02996ttx50

c-clips notoriously fail resulting in minor vac leaks, and the even sometimes LOOK clipped, and are not.

SEA996TT

Would a leak on the intake side of the throttle body (y-pipe) possibly cause a high idle condition or would that be more from whatever small leak is up front in the engine.

Have not yet been able to look for that yet, and haven't tried warming the engine up to see how it idles. More time later in the week. Just wondering if that might have been a big possibility or not much at all.

Thanks.

cburke996

My money is on the check valve that stems off the top of the intake distributor (Plenum, the plastic piece that the throttle body bolts to). The check valve goes from the top of the intake distributor, to a plastic line ending at the inlet of the driver side turbo.

SEA996TT

Great, thanks! I'm home tomorrow so I will get a chance to look at it then or this weekend. For my own education as I learn more about our car, what makes you think that it is the check valve?

cburke996

It is a pretty common point for boost leaks, I'm surprised it wasn't brought up already. The valve is item 16 in this diagram:

http://dcauto.gotdns.com/illustration/index/472438282

Mine was bad about 2 years ago, it was the source of a bad boost leak that I was chasing for a few weeks. If you determine this is your issue, be careful removing it. I couldn't get it to pull off the hose, and actually broke the hose barb coming off the plenum. Had to replace that as well, an extra $300 or so and a few hours time. Here is my thread from this:
https://rennlist.com/forums/996-turb...bar-today.html

"02996ttx50

yes, any minor leak can contribute to hi idle/hunting conditions.

SEA996TT

Finally got to spend some time on it today, lowered the engine for a better look and smoked it.

Found some smoke coming from the left turbo area so I removed the bumper, left rear wheel and inside of fender. Found that the pressure pipe coming out of the intercooler was a little loose, like the clip and slipped. Hooked that back up and tried again, found smoke from the upper part in front of the engine. Since I had lowered the engine you can see back there better, and found a crack on the mounting bolt on top of the left side black intake...the part that is just left of the throttle body, seems to be under some fuel stuff and probably a mixing manifold. Either way, not good. At least I have done the diagnostic work and gotten to know her parts better!

Pictures show crack in whatever manifold that is.

Kevin

That's your Bank one intake manifold. The damage usually occurs when the clutch is replaced. Not enough support or care is taken when you remove the gearbox. If you look at the underneath sound panel you might see the weld stud that has a fastener right above the intake. The metal stud will and can crack of poke a hole in the plastic manifold or in your case make contact with the aluminum side intake plenum.

SEA996TT

Gotcha, thanks Kevin. I learned a lot about the car getting in there and seeing how things work.

You are saying that a fastener above the Bank one intake pressed on the bolt on top of the manifold, which cracked it?

Regardless, I believe taking the engine out might be the best way to replace it and see if there is another leak forward of the manifold. Did appear that there might be a leak where the Bank one intake manifold connects to a hose up front, but I couldn't see where that went. Looked too far away to replace without pulling the engine.

In my garage, without a lift...probably not a project I can do. Time to get a pro to take it from here.

For others diagnosing leaks, I created a smoke machine from my Halloween fog machine, then used my Lowes created pressure test kit to pressurize the system. Lowering the engine was not difficult and without the extra room to see I would have never found the leak. I pressurized the system, saw some smoke and sprayed soapy water where I suspected leaks. Found bubbles, found a leak.

Lowes created pressure system was about $25. PVC plug screwed into male adapter. Drilled a hole in the end, screwed in an adapter for my compressor that included a guage and valve.

cburke996

I know its not "proper" but some JB Weld would seal that up just fine I'd bet.

rmc1148

I was thinking the same thing about repairing and doing it properly when engine is out for other work.

dprantl

I would do the same. Just make sure you clean that oily residue up before applying the JB Weld, otherwise it may not adhere properly. Buy the part and replace it when other work is needed.

Dan