02 Sentra Using lots of water

I have an 02 Sentra with the 1.8L engine that is using lots of water. There are no external leaks anywhere. When I start it up and let it get warmed up I get lots of white smoke out the tail pipe. Much more than when it is cold. I thought it was a blown head gasket, but I checked the compression and all cylinders are showing 150 pounds. My next guess is a cracked head. Does this sound like a cracked head? I am in the process of pulling the head off so I can take it to a shop to have it checked. Just wondering if there is anything else I should be looking for.

Thanks.

water? are you sure about this one?

here is from the FSM for the qg motor. seems that 168 is minimum though.

http://i13.tinypic.com/300to9k.jpg

yeah i was going to say it should be more like 180, id say your head may be warped or your gasket gone

I was expecting to see more of a difference between cylinders. When I tested them they all came up with the same reading. Usually I get one or two that are lower than the rest. I should have the head off tonight at at a shop tomorrow.

Thanks for the input.

If your getting a constant for all the pressure, then you could potentially have another internal leak that is not in the cylinders. It happens, not common, but that would explain a constant low pressure in all cylinders, because it all balances out. Ever had any significant overheating or heating issues of any sort?

I just got the head back from the shop and it pressure checked ok, but it was a little warped so the shop milled it. I don't know where else a leak would be. From what little I know about the owner, it would not suprise me if she had overheated the motor.

try it out, i knew it would be warped but i would like to see if that was all of the problem, have the comp rechecked after you re install head and new head gasket and get back to us, i want to know about this one

I figured it would be warped, but if you got that kind of compression it was probably warped from corner to corner. That could cause low pressure in all cylinders. Hopefully that works for you.
When reinstalling, make sure those bolts are torqued in good and tight. Hopefully the mill will fix the engine.

when you put a head back on, pls use an accurate torque wrench, use nissan's torque specs, not chiltons, and use correct tightening sequence. it can help prevent alot of problems in the future. you may know this already but still you may not.

When are you putting the head back on?

I torqued the head down according to my Hayes manual, but now you have me concerned that I did not do it right. I downloaded a manual from another post, but the file was corrupted and I could not read the part about torquing heads. Is it safe to untorque and retorque a head? What does this do to the head bolts? The instructions I have say to torque them to a certain spec, and then turn them 70 degrees and them another 70 degrees. Does this sound correct? Do I need to replace the bolts and start over?

Thanks.

nah, as long as they are all exactly uniform, you did them all the same way your head should be lined up good