Leakdown test / How to

[dsa87gn]

Sorry for the lame post but... how do you perform a leakdown test ? I'm a little curious/nervous that I have a headgasket problem.

When I start my car, I notice white steamy smoke coming from the pipes. It doesnt smell like coolant, more of a rich smell. After the car is good and warmed up the smoke is gone. I checked the oil and it is clean, although it has a slight gassy smell. The coolant also looks fine.

I am going to run a compression test on the cylinders but am not really sure how to perform a leakdowwn test..

Couple other notes...
If the car sits and idles for a while there will be some small puddles of condensation under the pipes

I first really noticed the smoke after putting the hooker cat back (test pipe) on. Could I be burning the oils off of the pipes ? They were slimy as hell out of the box.

 

[tom h]

A Leakdown Test is more of a pain to do than a plain compression test ... the justification is said to be that Leakdown gives a more accurate assessment of condition of piston rings & valves, and their ability to seal.

You need a Leakdown test guage setup, eg Tavia. I have one, it was about $70 a few years ago. Jegs and Summit sell them.

The engine has to be warmed up for most accurate results, and then the cylinder you're going to test is set to TDC on compression stroke (that's the PITA part). The engine is left untouched during the test, no cranking.

A compressed air source is hooked up to the tester, and a small volume of air flows thru the tester and into the cylinder. The Tester is basically 2 guages in a small manifold, with a small internal orifice between the guages. The air flow into the cylinder creates a pressure drop across the orifice, which is measured with the 2 guages. The tester is furnished with a chart that relates the observed pressure drop to "% leak" in the cyl.

Can't say I've used it too much ...