leak down test?

[flatout]

what is a leak down test,do ya just go thru and inspect all your vacc. lines or is there a science to it. god knows my poor old '90 could use all the help she can get.
thanks,
M

 

[Flyin-Low]

I leak down test is where you pressurize your intake system and listen for any leaks throughout your intake system. This is accomplished by taking off your intake and putting a device that you make in its place. go to www.vfaq.com - and under intake there is instructions on how to do it.

 

[Mr. Talon]

'leak down test is where you pressurize your intake system and listen for any leaks throughout your intake system'

really ^^^??
i thought a leak down test was when u put a cylinder to TDC, then presurise it with air ( form the spark plug hole) then see what percent of the air pressure that u put in is leaking out. By listening where the air is leaking to (intake, exhasut, bubbles in radiator ect.) you can determine what needs to be fixed. this test is usually done when the results of a compression check show that somethign is wrong. The leak down test just pinpoints the problem (atleast points u in the right direction)

hope that helps

trevor

 

[boostedinaz]

EDIT: Oh man he got to it before I did

Actaully that is a pressure tester. I leak down tester looks like a compression tester but it has two gauges instead of one. what you do is hook it up to a compressor and screw it into the sparkplug hole. You then pressurize the cylinder. The second gaue will show you how much is leakign out of that particular hole. If the sound of leaking air is comming out or the intake then some of you valves are nto sealing correctly. If the noise is comming from the dipstick then you rings are not sealing well. If it doesnt leak very much then you are ok. Not sure what the exact service standard for our car is, btu it should be in a Haynes or Chiltons. You do have to turn the motor before doing this untill all the valves on the hole are closed or else it wont work.

Hope that helped. Anyother questions feel free to ask.

Michael

 

[flatout]

thanks for all the answers i may have asked the wrong thing
the thread was "I CAN'T STRESS THIS ENOUGH" i was guessing that he was talking about vaccum stuff like hoses an such.
but thanks for the info from all
M