How does one do a leakdown test on an R56S? Ive searched on youtube but i dont see anyone done such a test on an R56S!

 

It's the same as on any other engine. Set the cylinder to TDC, thread the adapter into the spark plug hole, hook up the compressed air, and take readings.

 

Genii,

Most leakdown kits come with instructions. Maybe search for instructions based on your kit, but if you still need info I will gladly send you a copy of mine.

 

Thanx Austin, i don't have a kit, i just want to know so i can be more aware of what its going to be done to my car, when i do that test!

 

The simple answer:

Your engine will be held at TDC for a given cylinder while air is pumped in the spark plug hole. The gauges will measure how much air is going in versus how much is leaking out. The number, usually a percentage, reflects how good the sealing is around the combustion chamber while the piston is at TDC. This is done for each cylinder in turn to get an idea of how all of them are doing.

Additionally, you can listen for air hissing out. If you hear it at the intake snorkel, the intake valve(s) are leaking air past them. If you hear it at the tailpipe, it's the exhaust valves leaking. If you hear it at the oil filler, the rings are letting air past.

A little leakage is normal, lots of leakage isn't.

 

Thanx
1. What is TDC?
2. Can this test be done using fluid?

 

TDC = Top Dead Center (piston at the top of it's travel - farthest away from the crankshaft)

I don't think it would be a good idea to use a liquid.

 

http://en.wikipedia.org/wiki/Leak-down_tester
all you want to know........first two on google....

 

I didn't like the liquid option myself, but this technician proposed it. Perhaps i didn't understand. Anyhow, has anyone ever heard of using some liquid for a leak down test?

 

+1
hmm...think you misunderstood what he was saying....
any liquid would be forced out the exhaust...and flood the motor, intake, turbo...
A compression test is sometimes done "wet"...that is a soonful of oil added before doing it....

 

Was the technician talking about pouring a small amount (tablespoon) of oil down the spark plug hole first? The is called a "wet" test and I think is usually only used for compression testing.

 

I can't remember him saying that, but since im not an expert i can be wrong!
So regarding the leak down test, its not like i have to see a video done for an R56S, its the same procedure done on any vehicle. Since i saw the video Zippy uploaded here (and thanx Zippy) then its the same thing for an R56S. Correct?

 

Yes, a leak-down test is a leak-down test. It does not differ from car to car.

I've no idea what your mechanic was talking about with fluid and a leak-down test.

A compression test is a little different than a leak-down. With a compression test, you screw in a pressure gauge in place of the spark plug, and then crank the starter. (Disable the fuel injector as well.) The gauge will show you how much pressure is in the combustion chamber, which gives you an idea of how well the rings and valves are sealing over the full range of their travel. This one can be done "wet", as mentioned, by adding a little oil first. That will help the rings seal better, and if a low reading does not improve that way it points toward the valves not sealing well.

Both of these tests are done to get some idea of how worn the "top end" of the motor (the valves, rings, cylinder walls) are sealing. Typically a compression test will be done first, and if that shows problems the leak-down test will be done to help pinpoint them further.

 

So correct if im wrong here, the compression test shows how well either valves or rings seal? Is that right?

 

compression tests shows how all of them are working. so if the compression test is low, you don't know what the issue is, valves/rings/HG

leakdown allows you to slowly move the piston under compression and find the leak (listen in the exhaust, listen in intake manifold, listen in oil fill)