Tools for Compression test & Leak down test

[yhp2009]

Any recommendation on what to buy (company/brand/model) to ensure accurate home testing? As I understand it these gauges can be very finicky and read wrong numbers.
Just wanna see what people are using for a reliable result

[exodus454]

Having used Snap-on and Autozone, it's less about the accuracy than the comparison between cylinders. There's much variability in compression and leakdown testing vs what the spec is. IMO just don't buy a garbage set and you should be fine.

[yhp2009]

Having used Snap-on and Autozone, it's less about the accuracy than the comparison between cylinders. There's much variability in compression and leakdown testing vs what the spec is. IMO just don't buy a garbage set and you should be fine.

I see, so far I've found that the e46 m3 should have somewhere around 180-210psi. But im concerned that i'll find all cylinders pushing 150ish. What is the acceptable pressure range realistically... if anyone knows from experience

[eacmen]

I have used this for leakdown test seemed to work well.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[LightlyToasted]

I have used this for leakdown test seemed to work well.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I have the same and other related kits, and have used them a few times. Cannot testify to accuracy, but is consistent between tests on the same cylinder. Price was right; no complaints.

[yhp2009]

Nice, appreciate the suggestion. Ill check them out for sure

[stash1]

I see, so far I've found that the e46 m3 should have somewhere around 180-210psi. But im concerned that i'll find all cylinders pushing 150ish. What is the acceptable pressure range realistically... if anyone knows from experience

If you’re performing it on a warm engine (recommended), you should see between 170-180psi. If the motor is cold, a little less.

[yhp2009]

If you’re performing it on a warm engine (recommended), you should see between 170-180psi. If the motor is cold, a little less.

Will take note thanks for your input

[BigRussia]

Will take note thanks for your input

Apologies for bumping an old thread, but interested to see what tool you ended up with and what were your test results?

Im fearing I may have a failing headgasket and looking to do a compression test at home as well, as my indy wont be available for almost a month. Car runs perfect, no pinging or weird issues, other than water temp running hot at the track, even with fresh distilled water + wetter mix and good cooling system components. Perfectly fine on the street, so things are starting to point to maybe a bad headgasket, which at 180k miles and more than a handful of track days seems likely

[yhp2009]

Havent had a chance yet, waiting for better weather but i got a long list of things. Will let you know if i get around to it

[liam821]

It's gonna be slightly different between tools and temperatures, just worry about the differences between cylinders.

[foolio]

I have these. Well priced and seem pretty good quality.

https://smile.amazon.com/OTC-5609-Cylinder-Leakage-Tester/dp/B0030EVL60/ref=sr_1_3?crid=9P2S0SJ7J2I2&dchild=1&keywords=otc+leak+down+tester&qid=1614523294&sprefix=OTC+lea%2Caps%2C187&sr=8-3

https://smile.amazon.com/OTC-5605-Deluxe-Compression-Tester/dp/B004K2FSXI/ref=sr_1_2?crid=9P2S0SJ7J2I2&dchild=1&keywords=otc+leak+down+tester&qid=1614523842&sprefix=OTC+lea%2Caps%2C187&sr=8-2

[Irhase46m3]

Hi There - I just performed these tests not to long ago, engine has about 143k miles, its a 2004 which to my knowledge has never been tracked. I just want to leave these here as a data point so that someone can compare with mileage/age and possibly serve as a baseline:

Compression test: scored a 180PSI on both hot and cold across al Cylinders

Leak Down:

Cyl 1: 4%
Cyl 2: 5%
Cyl 3: 3%
Cyl 4: 3%
Cyl 5: 3%
Cyl 6: 3%

Hope this helps anyone!

[pawa_k2001]

Recently did compression and leakdown on my M3. Less than 5% leakdown is good, 5%-8% is ok, under 10% is acceptable. Compression on a S54 is usually in the 185-195psi range.

My M3 has 62k miles but is driven very hard.(track days and back roads, never regular driving)