Leak down test help

[matt98eclipse]

Hey guys im in the process of doing a leak down test but wanted to make sure im doing it right. Is there any link on how to do a leak down test for the 4g63? Or any good helpfull tips i should know? My compression before use to be like 100,115,130,150 and now tonight i did a test and it went up to 135,135,138,150.

 

[Spln_Hrd]

Bring the cylinder up to tdc compression on the cylinder being tested and then hook up the tester and read it basically.

 

[spoonman]

When rotating a cylinder to TDC, don't go past TDC and then back. If the rings are not seated against the bottom of the lands, your readings will be low. If you have excessive leakage, use your ear to locate the cause. Pop the oil cap off and listen for a hiss (blowby from rings or worse), next listen at the exhaust pipe (exhaust valve) and finally at the intake with the butterfly open (intake valve). This will isolate your problem and direct you to the proper corrective action. I hope these tips help.

When you did the second compression test was you engine still warm?

 

[matt98eclipse]

Yes i made sure the motor was completely warmed up. So basically the motor just needs to be at TDC on the compression stroke to make sure all the valves are closed.

How many pounds of air should i put in cylinder when testing?

 

[spoonman]

I also have this article that is related to our motors but more all engines in general.

http://www.geocities.com/dsmgrrrl/FAQs/leakdown.htm

Some mechanics use 100psi as the input pressure because 100psi gauges can be used which relate to 100% but there is no necessity for pressure beyond that. Any pressure above 15psi will function for measurement purposes although the sound of leaks will not be as loud. An engine pressurized to 100psi can rotate it not locked a TDC with that pressure so it is safer to use only 50psi which is what I use.

I asked if the engine was warmed up because if the engine is cold instead of warm the rings will not seal as well.

 

[matt98eclipse]

Awsome man thanks for the help and link. I tryed to click on the leak down link on vfaq but it doesnt work for some reason.

 

[Boost92awd]

You can also pull the dipstick out and listen there for leaks. If you hear air escaping through the dipstick, it means that your rings are bad.

 

[DroopYeyeS]

A leak down test uses oil in the cyclinder to help indicate whether compression loss is due to worn rings or other issues. How much oil did you put in each cylinder? The oil helps to seal the ring to isolate the sourde of the loss. Based on your reading I would say that your rings are in real need of replacement asuming proper test procedures were followed. Good luck with it.