does anyone know of any shops that can do this? i’m looking for one close to albany if possible
what kind of vehicle.
i’ve heard the term mentioned before. what is this exactly?
A leak down or “cylinder leakage” test is similar to a compression test in that it tells you how well your engine’s cylinders are sealing. But instead of measuring pressure, it measures pressure loss.
A leak down test requires the removal of all the spark plugs. The crankshaft is then turned so that each piston is at top dead center (both valves closed) when each cylinder is tested. Most people start with cylinder number one and follow the engine’s firing order.
A threaded coupling attached to a leakage gauge is screwed into a spark plug hole. Compressed air (80 to 90 psi) is then fed into the cylinder.
An engine in great condition should generally show only 5 to 10% leakage. An engine that’s still in pretty good condition may show up to 20% leakage. But more than 30% leakage indicates trouble.
The neat thing about a leakage test (as opposed to a compression test) is that it’s faster and easier to figure out where the pressure is going. If you hear air coming out of the tailpipe, it indicates a leaky exhaust valve. Air coming out of the throttle body or carburetor would point to a leaky intake valve. Air coming out of the breather vent or PCV valve fitting would tell you the rings and/or cylinders are worn.
A leakage test can also be used in conjunction with a compression test to diagnose other kinds of problems.
A cylinder that has poor compression, but minimal leakage, usually has a valvetrain problem such as a worn cam lobe, broken valve spring, collapsed lifter, bent push rod, etc.
If all the cylinders have low compression, but show minimal leakage, the most likely cause is incorrect valve timing. The timing belt or chain may be off a notch or two.
If compression is good and leakage is minimal, but a cylinder is misfiring or shows up weak in a power balance test, it indicates a fuel delivery (bad injector) or ignition problem (fouled spark plug or bad plug wire).
Thank you. Now, I’m interested in cost as well.
Vot. You worry a lot.
Nice post by smith.
i’m like a car hypochondriac
Enjoy your car. It’s an import not a domestic. It will last.
:smile I am curious about engine wear in general though. I want to do a basic analysis at blackstone labs, just to see how it is.
this is my brothers car, it is a 1995 mitsubishi eclipse with a 2.0 DOHC
is it having problems?
it is burning oil. it doesn’t go through a lot, but if i come to a stop once a blue cloud comes over the car and at idle it just bellows out of the exhaust. I’ve been told its the valves and then i’ve been told its the piston rings. Then i was told a leak down test would tell me where the oil is going, or at least give me a better idea.
Northstar did a leak down test to my car on the old motor…not sure what they charge tho.
They change nothing they tell you what the problem is.
I think you should read my earlier post.
he said charge not change. if you are talking about andrews post.
oil leaks are kinda tricky. my escort was starting to burn some, but we never got a chance to find out what was leaking oil, it blew the headgasket and it cost more to fix it than the car was worth, so we got rid of it
my bad
stupid F’in retard! :catfight :tong
i know my head gasket is bad. its leaking in the back of the motor. I have a new head gasket and oil pan gasket and valve cover gasket. But i want to get this test done just to make sure its not the valves or piston rings so i don’t have to get new gaskets again and go through all this crap again. I’ll be doing the gaskets and stuff myself, with my brother helping probably, so its not going to cost much more then what i’ve spent. Just food for the sentra fag for helpin. lol
If you’re head gasket is leaking it will yield useless results. A LD test will not decipher what the issue is, it just informs you the sealing condition of the cylinder(s) in question. You should just pull the head and get things repaired if the gasket is leaking. Driving on a blown gasket will only make things worse in a multitude of ways, including permanent damage to the head that cannot be repaired(cost effectively that is). If you pull the head and have it completely gone through(typically 2-250 per 4cyl head head here) and install a new gasket, THEN do a leakdown test your results will show you the sealing condition of the existing rings and new valve grind. I’ve got two pallets worth of stacked 420a core heads here at the shop, they’re known for issues to say the least.
If it’s buring oil:
Smoke on decel usually indicates worn valve guides and/or stem seals
Smoke under accel usually indicates worn rings, wall scoring, excessive cylinder taper, etc, etc
faulty pcv system can yield smoke as well pending motor condition and system setup.
Just things to consider here that’s all…