I was reading on Fresh Alloy that some people are making a boost leak detector for around 5-10 bucks using parts from Home Depot. The parts usually consist of:

PVC end cap
Valve Stem OR a Air compressor Chuck
Tape

Basically the idea is to find a PVC cap that will fit into the inside of the intake hose, drill a hose in the middle of the cap that is the same size as the chuck or the valve stem, mate the two together, then stick it in your intake. Tighten it down with either clamps or tape so it wont leak, and either use a hand pump or air compressor and fill it to about 15psi. Since the motor is off you can hear any leaks with the amount of air.

My question is, have anyone ever done this and if so, does it work?

 

Yes, it works. Why wouldn't it?
-Jeff

 

Dont know Never heard of it or done it before. So before I go and kick out the whopping $10, I wanted to get some feedback first. Maybe see if anyone has a revised version or a different setup that works.

 

the theory is solid. pressurizing the intake with motor off will allow you to hear the boost leak. I think this is a great idea! I might try it myself. Make something nice, so I can borrow it!

coincidentally, this is how you find out whats wrong with your motor when your leak down test comes out bad.

 

Good deal...so Im assuming its either a choice to use a valve stem or a air compressor chuck. One question I do have is...when it says to dump 15psi into the system, would one read the psi off of a boost guage or set the compressor to 15psi and unload it? OR does the boost guage need a vacum source to operate correctly?

 

You could read the pressure any number of ways. If you already have a boost gauge mounted, it should read the correct pressure (it should be on, if its electrical). If you used a valve stem, you could use a tire pressure gauge.

Ideally, the system would maintain 15psi until it you released it. Invariably, though, you'll lose some pressure through the valve seals and rings. I would say that you should be able to pressurize the system, disconnect the comressor (or whatever) and have plenty of time to listen for leaks before you have to pump it up again.

Oh, make sure you're not trying this with one of those valve cover breather things!

 

No valve cover filter....I'm going to go down today and see if I can put one together and give it a shot when I get some time.
I'll see how it works.

 

never tried it myself, but i've heard that they work.
some shops sell the kits for like 20$, but I know you can make one for less at home depot, thank god for home depot

 

It works!...Found two leaks so far...one leak very obvious, the other one was a clamp that needed to be tightened down more. Didnt have enough time to look for any more real closely due to rain BUT when I fixed the first two leaks, the system seemed pretty closed. After pumping 7+psi into the system, my dipstick hole spung a leak!. Does anyone know what could cause this to happen? It is because the car isnt running and there's no vacumn to hole it in? It does take quite a bit of psi to force it up, but the dipstick will come out of the holder by itself after enough air is pumped into the system. Could it be the wrong dipstick?

 

the dipstick seals tend to wear out sometimes. I'd try O-ringing it. It happens because the intake is connected to the valve cover, which shares the same air as the dipstick tube. Under vacuum, it would suck the dipstick back in.

There might be something with the PCV, aswell. I don't know very much about how they work, but I know it has something to do with venting the crankcase.