Leakdown test results

[x Spades x]

Hey Fellas,

So i just performed a leakdown test on the car i just bought a few months ago, and the results are kind of concerning. Cyl 1-6 all show 5% loss (96k mile engine). I also noticed fresh oil on each spark plug i pulled, as well as, oil on the tester after ever cyl test.

I was thinking maybe I need to buy 6 rubber spark plug grommets... would that affect the test?

Ill be installing 288/280 cams within the next month or so, so just wondering if I should pull the head or take apart the front end for the rod/rockers install?

Any insight?

[cobra]

Wouldn't consistent results across all cylinders be a good thing?

[Cubieman]

Try pouring a small amount of oil into the cylinder with the most leakage and see if it improves.

Also, the spark plug tube grommets only seal the valve cover to the tubes, those will not affect a leakdown/compression test.

If you are concerned your test results may not be accurate its generally the oring on the leakdown tool isn't quite sealing to the spark plug threads, but that would have shown itself on all cylinders likely.

You may also want to open the oil filler cap and listen for air, if air is getting past the pistons its in the crankcase.

My GT3 had a failure on 1 cylinder and I could place a rubber glove over the oil filler and it would inflate when I performed a leakdown test.



EDIT: If your results are consistent don't worry, do a compression test as well, if thats consistent and within spec your fine.

[bavarian3]

Did you try adjusting the crank after allowing the air to enter to verify TDC?

[bmwfnatic]

Good result, these tests are hard to perform

[x Spades x]

Try pouring a small amount of oil into the cylinder with the most leakage and see if it improves.

Also, the spark plug tube grommets only seal the valve cover to the tubes, those will not affect a leakdown/compression test.

If you are concerned your test results may not be accurate its generally the oring on the leakdown tool isn't quite sealing to the spark plug threads, but that would have shown itself on all cylinders likely.

You may also want to open the oil filler cap and listen for air, if air is getting past the pistons its in the crankcase.

My GT3 had a failure on 1 cylinder and I could place a rubber glove over the oil filler and it would inflate when I performed a leakdown test.



EDIT: If your results are consistent don't worry, do a compression test as well, if thats consistent and within spec your fine.

Appreciate that feedback. They all have the exact same amount of leakage, which is weird. I did this same test on my other E46 M3 a few months ago and got 1-2% on all 6 cylinders.

[x Spades x]

These are my leakdoen results from my other E46 M3 months back.

[x Spades x]

Did you try adjusting the crank after allowing the air to enter to verify TDC?

Yeah I did. These are the best air pressure results.

[x Spades x]

Try pouring a small amount of oil into the cylinder with the most leakage and see if it improves.

Also, the spark plug tube grommets only seal the valve cover to the tubes, those will not affect a leakdown/compression test.

If you are concerned your test results may not be accurate its generally the oring on the leakdown tool isn't quite sealing to the spark plug threads, but that would have shown itself on all cylinders likely.

You may also want to open the oil filler cap and listen for air, if air is getting past the pistons its in the crankcase.

My GT3 had a failure on 1 cylinder and I could place a rubber glove over the oil filler and it would inflate when I performed a leakdown test.



EDIT: If your results are consistent don't worry, do a compression test as well, if thats consistent and within spec your fine.

I just did a compression test... these are the results

[Flow]

That's perfect honestly

[sbay]

I just did a compression test... these are the results

On the money

[fattycharged]

if all consistent, would attribute it to tool used, especially with those compression numbers. Looks healthy af

[x Spades x]

Noted... thanks for the feedback everyone. I guess ill leave it be and take apart the front end when installing the Schrick cams