Answers to the questions we get most about boost leak testing.
Pick your make on Shop by Vehicle to see the kits made for it. Not sure? Text a photo of your turbo inlet or intake pipe to 248-403-8512 and we'll tell you which kit fits before you order.
Measure the outside diameter of the turbo inlet (or the pipe the tester goes on) with a tape measure or calipers, then match it on our What Size Do I Need? chart. A photo with the tape measure across it works too. Just text it to 248-403-8512.
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Most kits come with a 30 PSI boost gauge. Some end caps use a 15 PSI gauge, and the Duramax Pro-Kit, Duramax Shop Pro-Kit and Charge Air Cooler (CAC) tester use a 60 PSI gauge. The Duramax Base Kit is 30 PSI.
Every product page lists exactly what is in the box. Kits typically include a billet aluminum end cap, a boost gauge, a T-bolt clamp and air fittings (tire valve and compressor fitting). Universal kits also include a silicone adapter. Kits sold with an extension line add a 5 ft hose with a shut-off valve, and some also include a pressure regulator.
Yes, of course. Since the pro-kit offers a mounted boost gauge, it allows you to monitor the pressure going into the system. All you need to do is attach the boost leak tester to your turbo inlet and pressurize the system.
No. Basic tools are needed if you need to get to your turbo inlet, for example a screwdriver to remove a clamp off the turbo. It's recommended that you or a friend have an air compressor to pressurize the system.
Purely preference, but there are some differences in how you test:
Tire valve: shoot air in like inflating a tire, let off, then watch the gauge to see how your system holds boost. Pros: easy to watch bleed rate when letting off; no regulator needed. Cons: may need a partner to hold the line on a stubborn leak; needs a tire inflator attachment.
NPT compressor valve: continuous air supply while you listen for leaks. Pros: easier to test alone; gives you time to feel around the engine bay; you're away from the tester in case it blows off. Cons: needs a regulator and more cautious compressor settings; harder to watch bleed rate.
Start with a low pressure (5 PSI) and work your way up in 5 PSI increments up to your max boost level. The rule of thumb is not to exceed what your max boost would be while driving. You'll catch the big leaks first. Fix them and retest, since there may be another leak lingering at higher pressure.
A boost leak sounds like a steady hiss of escaping air once the system is pressurized, and larger leaks are usually easy to hear. For smaller leaks that are hard to pinpoint, spray a soapy water solution over the hoses, couplers, clamps and intercooler connections. Escaping air will form bubbles right at the source of the leak.
If you can't build any pressure, make sure all the lines are connected. If they are, increase the test pressure. If you still can't build boost, you either have a very large leak (which should be audible) or your air pressure is being lost through a different route.
Typically, when testing at an intake pipe before the turbo, you must plug the lines on the intake pipe between the tester and the turbo. These are usually crankcase lines that don't see boost and will direct air pressure into the crankcase instead, preventing you from building pressure.
