Yo guys, I'm having a massive oil consumption issue (2 quarts every 400 miles) on my 2008 Cooper S with 147k miles and I know the valve cover / PCV system was changed 47,000 miles ago by last owner at dealer with older part#11127585907 (newest is 11127646555). The turbo is original and I suspect the seals are shot not sure. I fixed all other leaks/gaskets and Im getting no white/blue smoke ever.

Before I spend $320 on a new valve cover or put in a new turbo I figured I'd compression test the motor to make sure the engine is healthy.

You'll need a compression tester with an M12 spark plug adaptor. I used the OTC 5605 Deluxe Kit which includes an M12.



Not all the kit's parts are shown in this pic as I was using some of them:



Anyway its easy. A one-man operation, but more fun with a friend.

1. Take out all 4 plugs (Deep well 5/8 inch spark plug socket is best or a 3/16 12 point with some Blue Tack will work but the spark plug specific socket will allow you to feed the plug in better when reinstalling) which means youll need to also removed the 4 ignition coils as well. Number all of them with a sharpie (plugs and and coils) as you pull them out so you can link back to any symptoms.

ECS sells one: https://www.ecstuning.com/b-schwaben...et/s-3858-125/

2. In the passenger side footwell fusebox pull out the 20 amp FUEL fuse (has the fuel pump picture).





3. Look into the spark plug wells and make sure the spark plug seats are clean so that when you put the compression checker on you make a good seal of the black o-ring.

This cylinder had a lot of black soot on the plug seat...I did my best to clean it out. Yes some will fall into the cylinder.



4. Use the M12 adaptor and attach to the end of the long metal extender tube and HAND THREAD until snug into any of the spark plug holes. You just need to squish the o-ring so dont get overzealous while tightening.

NOTE: Its VERY important that the M12 adaptor be on very tight because if it comes off when you unthread the entire metal extender from the spark plug hole you're gonna be in a real bind; The M12 adaptor will be threaded in the plug hole and there is no room to put a socket around it in that tight space to take it out. This is the only part of this kit I dont like. The adaptors have the potential to be left inside the spark plug hole with no easy way to get them out. So make sure the M12 adaptor is very tight and then only snug down the extender tube and M12 adaptor into the spark plug hole. You only need to seat the rubber o-ring in the plug holes, it doesnt need to be crazy tight.

5. Plug in the pressure hose and dial to the metal extender.



6. If you have a jumper battery or a jumper box now would be a good time to hook it to the battery cause youre gonna be starting the car 8 times for ten revolutions each. This will help supplement the car battery. I have an old plug in jumper box I used.

7. Get in car and hit the start button and allow it to crank 10 times and then press it again to stop the starter.

8. Get out and read the gauge and write down the PSI you've obtained for that cylinder. If you smell some fuel its ok, especially if the car was just moved and was cold. If you smell a LOT of fuel, you didnt pull the correct fuse.



9 Release pressure on the gauge to set it yo zero again.

10. Repeat with the same cylinder and write down PSI again.

11. Do the same for the remaining 3 cylinders; two runs per cylinder

-You shouldnt see a variation of more than 10% across all 4 cylinders (~18 psi in MY CASE).

I did it with my engine cold but some prefer it hot because the metal has expanded and you get a true operating-temperature reading.

Some will also add a teaspoon of engine oil (preferably 30 weight if you have some handy from a lawn mower) into each cylinder to better seal the piston rings and then try the test.

The more important result is not so much the absolute # but rather the variation across cylinders.

I got the following from my old dog:

Cylinder 1: 165psi, 168psi (average of 167)

Cylinder 2: 170, 170, (average of 170)

Cylinder 3; 165, 175 (tightened tool a little more on second test; average of 170)

Cylinder 4: 160, 165 (tightened tool a little more on second test, average of 162.5)

My max variation is 7.5 psi, about 3-4% which is fine.

Since I have less than 10% difference across cylinders so the seals in the combustion chambers are good. Had the variation been greater than 10% I would have done a leak down test to pinpoint the failure.

My plugs looked kinda gross after 20,000 miles. Now is the time to look at your plugs to help diagnose issues and check the gap.



Anyway guys, Im no pro so please feel free to add any additional tips and tricks.

As the oil consumption, I checked 3 places in the intercooler plumbing and found a little bit of oil right after the intercooler but I cant say its excessive, then again who knows how much is sitting in the bottom of the intercooler proper.

Right after turbo into 1st section of intercooler plumbing looked dry:



Right after intercooler next to AC compressor was kinda wet, the inside of that pipe was slimy for sure. Oil is likely pooled in this low spot and trying to make it was up under boost.





Top section after MAF and before throttle body was dry. Looks like most of the oil is sitting in the low spot (intercooler) and not making it up to the MAF, in heavy quantities anyway:



So I still dont know for sure if my turbo seals are bad, PCV or both. Im gonna try the cheaper option first, the VALVE COVER. $313 ECS Tuning.

 

If you're writing this procedure for a novice, you should also tell them to reset the compression gauge right after writing down the reading. A good gauge will hold the last reading for quite awhile. Also, the spark plug socket size will vary according to the plug part number.

 

Yes indeed! For novices like me.

ah yes I forgot that detail. Will add it now. Thanks.

Love that bulldog!

 

thanks! I've been putting this off for to long, my car is up over 120k and been meaning to do a quick test.
since this is the only car i'll ever bother to do this to, i went a little cheaper and bought:

&
the gauge itself feels a little cheap, worked fine, but the rest of the pieces are well constructed, nice orings

after testing, my car is quit a bit lower across the board 110-115psi on all cylinders. This was also done while engine still pretty warm - maybe 30min after drive. I also went back, applied teflon tape to all the threaded connections between all the adapters and extension and tested again, but nonetheless still got same readings.

 

I wouldn't get too excited about low readings, consistency is more significant. The equipment used can make a serious difference in the readings, especially long hoses. The longer the distance between the gauge and cylinder, the lower your readings will be. Also, the inside diameter of your hoses makes a difference --- the bigger the ID, the more air there is to compress. My gauge uses a large ID hose, and only reads 110 - 120, but when done by a pro with better equipment, the readings are closer to 160.

So, if the engine runs good and little oil consumption, don't worry about 110 - 115 readings, worry about big differences between cylinders, 15 - 20% max.

 

Yo, awesome bro. Glad you were inspired to try it.

I agree that the variation across cylinders is what counts.

Why did you check yours?

 

Mostly just checking health....want to go little bigger turbo
but its still up in the air
numbers good - maybe swap exhaust side on the hybrid i already have and end up with a decent k04
numbers not so good - worry about rebuild and big k04

 

BTW it was the PCV system (valve cover) which was the primary cause of my oil consumption. Once changed, oil consumption was reduced immediately and significantly.