2005 equinox 3.4 awd. i just installed a Remanufactured shortblock and remanufactured heads. I have no compression on #6 cylinder and only about 75 lbs on #4 cylinder. All others are good. I thought it was a head gasket problem so I removed the head, found no problems but replaced it anyway. Same issue. With the rocker arms off of the engine I get some compression in that cylinder. If the heads and block were milled during assembly could i need shorter pushrods?

P.*.I am aware that intake and exhaust pushrods are different lengths and I have them in the correct places.

Have you tried a leak down test? Should have been the first thing you did when you found no compression......

Thanks for responding, no I did not try a leakdown test before. I couldnt rent one so today i went and bought one. I tested all three cylinders on the front side (2, 4, 6) all at tdc and all with about 20 psi. All three showed 55-60% leakdown and all appeared to be going into the crankcase (rings I guess). Would this be normal for a rebuilt engine with zero miles? This all started when I put this engine in the car and started it, I kept getting code p0306 cyl #6 misfire. After checking all of the normal stuff (ignition, fuel injection etc), is when i did a compression test and found no compression on #6.

No, not normal.

You could try different kinds of magic to maybe make the rings loosen up and/or start sealing better, but in the end I think your best bet is to use the warranty that the short block should have come with.

I'm curious:Who is the rebuilder?

Again thanks. Mabbco out of Tyler,Texas.

This really sucks, that you put all this work into the engine, and you have compression problems......

There are so many of these engines in the recycle yard, that you can get low mileage with, and it becomes plug and play, at a reasonable cost.....

I believe that under 15-20% leakage is acceptable.......now all testers are different, and should be used accordingly(for example, some use 90 psi shop air for testing).......

60% leakdown? Holy crap! On a rebuilt? Surprised it even runs...should have been getting misfires all over the place......I don't understand, zero compression on #6, and yet it measures the same leak down on 2 and 4?

Sure you are at TDC on each cylinder(compression stroke), and are using the tool according to the manufacturer'* instructions? For example, did you calibrate the tool to 0% leakage before installing it?

I was pretty careful to get to tdc on compression stroke and set the gauge to zero each time. I thought it was pretty strange that all cylinders were showing the same leakdown percentage yet drastically different compression. Maybe I missed something, will test all again tomorrow.