I did not mention that you need to have the throttle plate all the way open for the compression test. I forgot to mention that because... well I had the whole intake manifold off my car when I did it
If that was closed your results will be wrong for all tests.
Also, I didn't mention that a leakdown test can be tricky to do accurately. Either you need a tester that can operate at low pressures, I don't think I ran into a problem until I hit about 75 PSI. Get about 5-10 PSI past that and the engine will turn itself over and open some valves... pain in the ass
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SO to do the leakdown:
Make sure the engine is up to temperature (careful, stuff will obviously be hot. wear some mechanics fabric gloves)
In your case, fill the coolant reserve tank until you only have a couple of inches empty space.
Get a jack and a jack-stand
Set the E-Brake (have to) and chock the rear wheels (if you can)
Loosen the driver's wheel lug nuts, just a little
Jack car from front driver's side jacking point until the wheel leaves the ground and there is room for the jack stand under the front suspension lower control arm mounting point/sub-frame. NOTE: You don't have to let the car off the jack if you are not going to be under it, but you may prefer to for your safety or peace of mind. The stand will hold the car without damage if the jack fails.
Never get under a car without properly positioned jack stand(s). If you put it in the wrong spot, the car will fall and the stand will not hold it (it'll just punch a hole in the floor pan). Of course, you won't care because you'll probably be dead. If you survived, you probably would be upset about that right then.
Finish removing the lugnuts and the wheel
You will need a large ratchet or breaker bar (1/2 inch drive is best) and appropriate socket (mine is a 17mm)
There is a round area with a cutout to allow easy access to the crankshaft pulley for occasions like this one.
F that. I don't use it, I pull the whole front mudguard. That makes access SUPER easy, and allows you to inspect other stuff.
Remove all the spark plugs
Loosen the top timing belt cover bolts - DO THIS BEFORE REMOVING THE VALVE COVER
Remove the valve cover
Remove the upper timing belt cover
You can now see your timing marks on the camshaft sprocket
Put the car in neutral
Using your rachet or breaker bar turn the crankshaft counter clockwise (honda engines are backward from everyone else's) unti you line up with one of the marks. These marks represent TDC for every cylinder, if you are lucky you have a clear mark on the crankshaft pulley to line up with the lower timing cover 0 degree timing mark (I'm not lucky, so I did it a different way). I used a very long (12") plastic zip tie dropped into the cylinder to tell me when I was coming up to TDC and then checked to make sure my rocker arms were loose. If one side or the other is tight, you are not on the compression stroke for that cylinder. Rotate until you get all the rockers for that cylinder loose (should match the timing mark on the camshaft sprocket, which lines up with a triangle cast into the cylinder head indicating TDC). Watching the zip tie helps you determine TDC if your marks aren't clear, the second the zip tie starts to move back down you're too far and need to back up until it seems to stop moving for a degree or two... that should be TDC.
Remove the ratchet or breaker bar, I left the extension(s) and socket on the crank bolt but taking them off is safest.
You're ready to attach the tester. Read the directions thoroughly, and do a youtube search for 'leakdown test' to see some other people do it. The harbor frieght leakdown tester is probably the most popular since it's about $40. It's not terribly accurate, but as long as you keep the input pressure the same all your readings will be the same amount of inaccurate (sounds funny, but that's fine). The directions are also a little misleading, so ask if you aren't sure (the youtube videos will help with set up)
Now, here's the tricky part...
If you set up your tester properly AND the cylinder is at TDC AND you keep the pressure low enough, the engine should not turn itself over and you will get a reading. Write the reading down and the pressure you got it at (ex. 67 with 75psi input pressure). You may have to convert these numbers later if you are using a lower pressure than the gauge instructions give you a table for. We can help with that.
If you CANNOT keep the cylinder from turning over you can do one of two things:
1) Do the test at BDC just before the start of the compression stroke (valves will be closed and the piston will be all the way down.
2) Find a way to lock the flywheel/flex plate in place. Yeah... that's a bi_ch. Screw that noise... that's easy with the transmission off.
DON'T BOTHER:
1) Trying to have someone hold the engine stationary with the breaker bar or ratchet. At best you'll get false results, at worst someone will take a wrench to the face and need their jaw wired shut and plastic surgery.
2) Trying to put the car in gear to hold it. It won't.
Repeat for each cylinder. If you have a huge variation on one cylinder listen at the following places:
Throttle plate - If you hear air rushing through either you are not at TDC/BDC with the intake valves closed or you have a valve that is not seating (check to make sure the rocker arms are loose on both sides)
Exhaust pipe - (same rules as above)
Dipstick tube - If you hear air here, it's going past the rings and the gauge value will tell you how much of your potential compression is being lost through them. At 100 PSI input a value of 80PSI on the leak-down gauge would indicate 20% leak-down (this value would be acceptable on a high mileage engine (200K+)) Any more than 20% is bad and any more than 10-15% difference between cylinders is probably going to mean a rebuild of top or bottom depending on where the sound is coming from.
Use a long piece of rubber hose held up to your ear to gather the sound at these places.
Also in your case, watch the coolant reservoir for major bubbles as you do each cylinder, that will pinpoint your leak there.
Or you could pay someone to do all that sh_t for you. Let us know if you need advice or clarification on anything.
Good luck!
