Leakdown Test??

[87national]

How do you do a leakdown test?

 

[equalizer442]

you need a leak down tester and some compressed air, you put the air line in to the tester and then screw the line from the tester in to the cly, when the cly is a bdc with all the valves closed. the gauges on the leak down tester will tell you how much blow by your getting.

if your getting alot of blow by in one cly then try a wet test, pour alittle oil in to the cly and do the cly leakage test again. if you have better compression then your rings or shot. if not you have a bent valve, burnt valve, cracked head, block, or head gasket.

while doing a cly leakage test remove the radiator and up pipe and plug one side of the exhaust (so its easier to feel for air) and notice the breathers. then if theres air coming out of the radiator then you have a blown head gasket or a cracked head. if theres air coming out of the exhaust you have a bent or burnt exhaust valve. if you have air coming out of the plenium then you have a bent intake valve.and if you have air coming out of your breathers then you have bad rings, cracked piston, or a cracked block.

 

[6PacktoGo]

Leakdown tests are done at TDC and not BDC, since when the engine is running, the highest pressure will be seen at TDC, and this is where ring seal is most important. The normal test pressure is around 60 psi, and the normal leakage is around 10%. Leakdown tests should be done with the engine as close to operating temperature as possible, if you are looking for accuracy.