Performing a leak-down test

[greenStar]

Hi guys, I have searched everywhere on this forum and could not find a single thread on how to do a leak-down test on our engines.
I am planning to do one myself, and have watched quite a few youtube videos already. I am planning to just buy a harbor freight leak down tester for the job.

Does anyone know the best way to turn our motor over by hand? (b7 s4 4.2L)

i was going to use the balloon trick to determine it is on the compression stroke,
and the screw driver in the cylinder trick to determine when its at TDC.

thanks


ps. please direct me to a thread if this has already been discussed in detail someone, if u know of one. Thank you

[greenStar]

ugh...seriously NOBODY'S done this?

[JimmyBones]

To do a cylinder leakage test on a B6/7 S4 I move the front end into service position so that I can turn the crank by hand with the Audi special tool or you can use a 24 mm socket to turn the alternator and thus turn the engine. Then to find out if the cylinder is on top dead center I stick a really long screwdriver down the spark hole onto the top of the piston, and turn the engine until the screwdriver stops going up. Make sure to go in the firing order of the engine or else you will be spinning the engine over a lot!

[greenStar]

Thanks Jimmy, for the tips. It's 1-5-4-8-6-3-7-2 according to this link http://ricksfreeautorepairadvice.com...-firing-order/

Question: in a car consuming oil, in your experience, what do u think I should expect to find?

My car consumes about a quart of 0w-40 european formula and Motul per week at the moment, and it has a few small oil leaks, probably a partially clogged cat, and 156k miles on the clock. It was a VERY clean car when I got it. Looks well cared for. The spark plugs had white deposits/crust all over some of them. I'm sure its probably burning some. BUT AGAIN what do YOU think I will find?

I have heard that some air coming through the oil filler/&dipstick tube is normal..??.. BUT HOW MUCH is normal?
Who knows..this all could be obvious when I do this...
Will air come from the intake & throttle body and be obvious if its a valve seat or valve stem issue? Will this typically be obvious and detectable?

Thanks very much in advance. I haven't found anything in the b6/b7 s4 section covering any of this. I am anxious to see what I will find.
Unfort its below 0 degrees outside, so this may have to get put off a few days or more! Love to hear your thoughts. ben

[Silver Streakin]

1 qt per week?

[RedS4avant]

Wow that's alot of oil! Your exhaust must be filthy

[greenStar]

What should I expect to see with the leak-down tests?

If there are worn or "bad" valve seals or stem seals (which is it) will it be totally obvious in leakdown tests?

I'm holding onto hope! !!


JFYI, compression ranged from 140-150 on all cylinders, and only two very light score marks were seen when the whole engine was boroscoped.
Exhaust is not very dirty at all. Looks relatively normal. I'm afraid a lot could be caught in the cats.
Valve cover gaskets, and front crank seal are also leaking some, and I wouldn't doubt that the oil filter housing and maybe valley pan seals are as well after reading all that I have read about these motors..

So I'm hoping the cylinders and block are still worth driving on and holding onto, upon some maintenance and testing!

[codyfisher]

do this for sure. I always share this link when I can
http://www.audizine.com/forum/showth...lved-on-my-car!

[greenStar]

do this for sure. I always share this link when I can
http://www.audizine.com/forum/showth...lved-on-my-car!

so funny you post this, bcos i was JUST reading this thread. I want to do this also

BUT don't see how this relates to leak-down testing and oil consumption though...?

[jr1415us]

so funny you post this, bcos i was JUST reading this thread. I want to do this also

BUT don't see how this relates to leak-down testing and oil consumption though...?

These vehicles have a couple places that are prone to leaks. Valve cover gaskets, and the valley pan area, including the oil filter housing O rings. Leaks can develop at the oil cooler block behind the alternator too.

That was linked, I'm guessing, bc some people
like to change out the oil check valves if doing the labor to change out the valley pan gasket.