Totally agree. But since 1 cylinder has no compression, the head has to come off anyways. Would I not be able to do visual on the valves, piston and cylinders to accomplish the same thing?

compression test only shows what is going with cylinders.... so to be more precise a leak down test can be don easily then it will show or you can hear air escaping from intake or exhaust valves.... a typical valve job will cost around 250 ish. If you are handy the head replacement job is very easy.

now it is clear to me. Thank you all for the clarification. I have ordered a leakdown tester. I will rent a compression tester from AUtozone.

Now my next question is regarding the cam holding tool. Is this tool neeed if all that I will be doing is replacing the head? or is this tool needed to prevent the cam from rotating while torquing the cam sprocket bolt? Any idea how to remove and install the cam sprocket without the cam holding tool? my car is R53 automatic.

get the tool and it costs only 33bucks on ebay. Worth every penny. It will assist you during the removal and installation procedure with ease. Torque everything to specs. Buy some engine assembly lubes. While removing the rocker arms be very gently so that the "tip" on them won't fall off

Good point on the cam holding tool.

I received the leakdown tester today and found that the adapter hose that came with it that connects to the spark plug hole has a Schrader valve. Is this correct? Shouldn't this adapter hose be a straight through hose? I do know that the adapter hose for a compression tester has a Schrader valve but I was not expecting the leakdown tester to have an adapter hose with a Schrader valve.

Yes,thread one end in the plug holes,then one will attach to air compressor (set it at 110psi). Set the pistons or cylinders at TDC (with a 1/4 extension or whatever so that you can tell its at tdc). Result of each should ve less than 10%,above means leakage

Thank you. I think I understand the connections but I am struggling to understand how pressurised air will flow into the cylinder when there is a Schrader valve in the hose that is connected to the plug hole.

Same dynamics of a Schrader valve in your tires; allows air in but not out.

Thank you. That is exactly my point. The Schrader valve in this case will allow air towards the meters from the cylinder. The hose adapter that came with the tester is the same as what would come with a compression tester. I am expecting the opposite.

just confirmed my suspicion. I have to remove the Schrader valve in order allow air pressure to go into the cylinder. I think they shipped the wrong hose adapter, but still workable after removing the schrader valve. See video below on how one guy converted a compression tester to a basic leakdown tester:

Hey banyan, What did you ultimately do?

This is the preferred way to do it, and is pretty much foolproof. I have done much engine work using this technique. The compressed air way is OK, but too much can go wrong.

One way to improve this is to use natural bailing twine, or jute or sisal string. This way any little fibers that are left will burn up and turn to ash, not potentially get melted onto a ring or cylinder wall.