tbarcelo

I'm in the process of doing a little maintenance / investigation / education on my car following some general discussions with Kevin M about improving my turbo response.

While doing a boost test (pressurizing just after the MAF, so I suppose that is a full intake test), I quickly found the driver-side inlet pipe was not fully connected to the turbo. After pulling that whole section apart, cleaning and reassembling, I went back to pressure testing.

I definitely have a leak, and it does not sound like it is coming from either the driver-side or passenger-side turbo areas. It really sounds more like it is on top of the engine, but reasonably far forward (i.e. the hard to reach / see area). Last night I stopped leak testing, briefly, to remove the DVs and lube them, but I plan to reassemble tonight and get back to pressure testing.

My question - does anyone have some good techniques for locating leaks? I plan to get a spray bottle filled with soapy water, but even with the engine dropped as low as I'm comfortable going (end of engine mount nut even with end of bolt), access to the top of the engine is lousy. I can see this process being very, very difficult.

Wealth Manager

Go to a local Indy shop and have them smoke test the car, it will show the leak.........its very easy for them to do.

tbarcelo

Can any pressure be applied during smoke testing or are you limited to 1-2 psi?

How do shops typically do smoke testing? Would they be removing airbox and MAF and sealing to the post-MAF tube?

thomapa1

I had my shop find and remediate my past leaks. They did multiple full pressure tests. One thing led to another and the shop owner worked on my car personally as it got more and more involved. about $2,500 in labor later - he was confident that he tackled all of the leaks. Replaced many clamps, hoses. Car has been rock solid since the work (about 1 year ago now)

Ended up also finding:
- Leaks at intake manifold sleeves - ended up replacing all 6 (careful as these need to be clocked properly at install). about $180 for parts
- Leak at intake distributor passenger side - basically a plastic piece that gave him fits trying to find. Leak was not evident until things heated up, then internal hairline cracks were evident as viewed under a magnifying glass. Replaced...$400 part
- Leaks at one or 2 injector O-rings
- Leaks at UMW rivet sealed wastegate, some of the rivets had backed out, resealed and added loctite - likely prior owner poor install technique.

Most of issues were on the passenger side (exhaust side?) assume because this side gets the brunt of more heat?
But I'm no expert. I paid for the expert to do the work.

Hope this helps your investigation.

kalio12

When I had my smoke test done at my indie, he removed the airbox, closed up the hole, fitted the smoke machine to the piping, and started it up. I'm not sure how much pressure can be applied, but if there's a leak, this method will find it. I had one boost hose halfway off and a broken wastegate. Hope this helps.

tbarcelo

Great, thanks for all of the input!

993GT

pressurize at the turbo inlets ~20psi, listen for leaks/ use soap and water/ pressure drop

32krazy!

if it was easy the shops wouldn't charge you to do it. test from the turbos use soap and water and prepare to have bloddy knuckles and hands. this is a hands on thing and the only way to fix the leaks is reach in there and get dirty. sorry

smoke test isn't the same as pressure testing. smoke test for vacuum leaks and pressure test for boost leaks

p556guy

There is a check valve at the top of the motor that comes off the driver's side of the intake plenum. I bet that's your leak.

993GT

^ one reason the airbox pressurize technique(should also be done) is flawed, test at turbos to test the check valve

Kevin

Why, pull the check valve and test it or replace it..

As mentioned the smoke test only get the easy leaks..

If you are testing at the turbochargers, you better re-test at the MAF intake to find the leak at the turbocharger that you missed when rushing to connect the inlet pipes.. The OP is the 3rd individual that has undone inlet pipes this summer. The ending result gets you a turbo rebuild!

drjones

Where is the check valve located?

Thanks

Darren.

993GT

top of engine near the driver's side intake manifold, see circled in red: