1999all_motoR_teg

Just a question for anyone that has used this model before. Want to make sure I'm using the tool right.

I know I have to put it to TDC and all that but with this particular tester(2 gauges) when I'm ready to perform the test do I turn the dial to force 100PSI into the cylinder then read the percentage of leakdown on the other gauge?? Just wondering if I should turn the dial to 100psi or lower like 90psi or something??

Sorry if this is a stupid question just never used this tester before.

TIA for any help

0mtber

iTrader: (2)

I found this information a long time ago on the forums:

10% isn't huge, but definately shouldn't be there with 24k on the clock. They should be about 2-5% with that few of miles. My old motor with 50K of raced miles and daily driving still only had 5% across the board. But the 5% was leaking out of the rings. My new motor is 0-.5%, which is where it should be.
Here is the appropiate way (my version) to do a leakdown test:

Its very similar to a compression test, but like someone said about, you are pressurizing the cylinders to see how much and where air is leaking. You can get a leakdown tester from Snap-On, Summit, or make your own, there were some old posts before about how to make your own. The leakdown tester comprises of a tube that has a female air line fitting on one end and a spark plug fitting on the other. The other part of the tester is 2 gauges, 1 1-100 PSI gauge, and 1 percentage leakdown gauge. On this part of the tester, it contains a **** that allows you to let air pressurize the system or completely shut it off. You will also need an air compressor that holds at least 100psi of pressure.

1: Make sure the engine has been run and was at operating temperature. Turn off engine
2: Remove all spark plugs, and rotate motor to TDC on Cylinder 1
3: Take off intake piping, oil cap, and radiator cap (careful, it may still be pressurized)
4: Thread the spark plug fitting of the tester into the #1 spark plug hole.
5: Attach the air hose from the air compressor onto the other portion of the tester, making sure no pressure is showing on the gauge.
6: Attach the female end of the gauge to the male end of the tube, slowly turn the **** on the tester until the cylinder is pressurized to 100psi.
7: Read the leakage gauge to see what percentage of leakage there is. Record that reading.
8: If there is leakage more than 0%, listen/look for escaping air from the following places:
a)Fully opened throttle body
b)Oil cap hole
c)Exhaust
d)Radiator cap
e)Any spark plug hole

9: After you trace where it is/isn't leaking, depressurize the cylinder, and un-hook the fitting.
10: Rotate the motor to cylinder #3, repeat steps 4-9
11: Repeat step 10 for cylinder #4
12: Repeat step 10 for cylinder #2

Analysis of leakage:
Leaking from Oil Cap hole: Most likely your rings are leaking, if you have air releasing into your crankcase, it means the rings are sealing 100% and there is air flowing passed them.

Leaking from Intake/TB: Air is leaking from your intake valves, probably need a valvejob or new valves depending on whats wrong. I had 11% leakdown from my #3 cylinder at one time, this was due to a bad seal on the valve seats and also one of my retainers was starting to crack which caused it not to full return into place.

Leaking from Exhaust: Bad exhaust valves/seats, on an over-rev, the exhaust valves are usually the ones that get bent. If you use nitrous, the exhaust valves are also the ones that usually get "burnt" or injured.

Leaking from Radiator: Bad headgasket

1999all_motoR_teg

Thank you for the info. SO I was right in turning the dial till it's at 100PSI and then taking the percentage readings.

I did so and it showed less than 5% in each cylinder

Pandahatch

I just used the Snap On tester for mine and I felt VERY VERY VERY faint air coming from the dipstick tube, not valve cover at all and the leakdown % didn't even read 0%, it was just below it. I had it at 100psi too...