Anyone know if there is an industry type standard that a leak down test should yeild.
Thanks,
Zach
Thanks,
Zach
Leak Down Test
- Thread starter ZACH
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96% to 98% is considered excellent -- I would start to worry below 90%.
It's more of a diagnostic/qualitative than a quantitative test. I wouldn't fixate on a %, but rather if you have leakage, WHERE is it? If simply a small amount at the rings, then you are clean, anywhere else (cooling system, valves,etc) and you have work/$ in the future.
My results were:
16-15-17-7
The reason that I am asking is really because I am one of those paranoid people
I have 3 cylinders that seal goood, and 1 that is **** good.
16-15-17-7
The reason that I am asking is really because I am one of those paranoid people
16, 15, 17%, as in loss?? if so, I would check hard at valve adjustment or seating...17% is alot of leakage.
I took it to the dealer and they said it was normal. I am on of those that checks the dealers work, and do my own work so I double checked it. I am a bit confused because this motor has 20,000 miles on it. Ill check my valve clearance etc...
That sounds normal. Of course, normal to a dealer is not normal to the rest of us.
I checked a few more sources. Under 20% is satisfactory. From my understanding a leak down test should only be used if a compression test shows more than 14psi difference in all cylinders. My compression test was normal.
Here is my understanding of what a leakdown test is:
Air is pumped from the air compressor to a pressure regulator (with a gauge), then through a restriction, then through a pressure gauge, then into the cylinder via the spark plug hole.
The % leakdown is the difference between the regulator gauge on the compressor side of the restriction and the pressure gauge on the cylinder side of the restriction. So, what you are measuring is how much faster the air is leaving the cylinder than what can come in via the restriction.
I don't believe that the restriction size is standardized, so only consider "acceptable" numbers from the makers of the leakdown gauge.
For what it's worth, I built my own leakdown gauge and used a .040" hole for the restriction and I pretty much had 10% leakdown in all cylinders.
[ September 05, 2003, 06:20 PM: Message edited by: Chris A ]
Air is pumped from the air compressor to a pressure regulator (with a gauge), then through a restriction, then through a pressure gauge, then into the cylinder via the spark plug hole.
The % leakdown is the difference between the regulator gauge on the compressor side of the restriction and the pressure gauge on the cylinder side of the restriction. So, what you are measuring is how much faster the air is leaving the cylinder than what can come in via the restriction.
I don't believe that the restriction size is standardized, so only consider "acceptable" numbers from the makers of the leakdown gauge.
For what it's worth, I built my own leakdown gauge and used a .040" hole for the restriction and I pretty much had 10% leakdown in all cylinders.
[ September 05, 2003, 06:20 PM: Message edited by: Chris A ]
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