I have a 03 a6 3.0 no compression . Timing belt was good . it was overheated before I got it drivers side zero compression pass side 30-30-0 . I am currently pulling apart to dig in deeper possible might need new engine any help would be great if I have to replace live in Pittsburgh area.

 

Overheated could mean warped heads, scored cylinders etc. Usually no compression means a problem with the valves, bad rings and scored cylinders means low compression. If you put a little oil in the cylinder and compression improves it is rings or cylinder walls, if no improvement it is probably valves. If you have a warped head it probably will not be all cylinders. Also, if the heads are warped you are usually leaking fluids or blowing bubbles in the coolant.

Even thought timing belt looks good I bet the timing is off and you have bent valves.

 

I would recommend doing a leak down test to see where you are losing compression before just taking everything apart. You may not have an issue that will just stick out at you like a sore thumb and a leak down test will help you go in the right direction.

ManyAudis gave some solid advice there as well. I would give all of these suggests a try before simply tearing everything apart. At least this way you will know what you're looking for when you disassemble.

 

Ok head is pulled head gasket was intact no holes or burnt marks looking at valves see no signs of bent valves doing a water test on intake no water leaking out could it just have been out of time will pull pass side head next

 

Oh cylinders still have there hatch marks on walls mid seating pistons n filling with oil they are holding

 

Ok update flip cylinder head over put plugs in fill with water holding water totally list could it just been out of time ?????

 

I'm betting you wish you did that leak down test now, right?

Did you have any CEL codes prior to tearing everything apart?

 

If the cylinders are fine and the valves don't leak there is only one way I can think that you could have gotten 0 compression on all cylinders with no damage. Someone did a timing belt job and got the camshafts exactly 180 deg out of phase.

There must be some history here that you have not told us or that the PO did not tell you.

 

I bought the car just a couple days ago my third Audi all I know is the line going to coolant bottle broke and it over heated then after that , the car would not run . Timing belt did not looked touched . Cracked and worn but not broken possible water pump seized up from being so hot ??

 

It's possible the water pump's impellers broke off of the shaft, thus stopping flow through the system. In time, the coolant boiled and began wreaking havoc on the entire coolant system and various other connected components. Once vacuum was broken, the coolant would boil at 100C and not do you much good.

As ManyAudis said, there's gotta something else going on with this engine that you're not aware of. The previous owner may not have told you everything.

If you were getting 0 compression on an entire bank of cylinders and an overheat condition occurred, it is certainly possible that heads are warped to the point of no longer being able to hold compression.

At the very least, it looks like you're going to need to replace the following as it's common practice when doing a timing belt, valve cover and head gasket job. Throw in a severe overheat condition and the list is scary:
Timing belt
water pump
water pump gasket
timing idler pulley
timing belt tensioner
thermostat
valve cover gaskets (Inners and outters)
cam chain tensioner gaskets (Though, this is a 3.0, so I'm not 100% sure about this)
half moon piece below cam chain tensioner
cam caps
cam seals
head gaskets
any broken/damaged coolant lines
expansion tank
new set of heads (possibly both driver's side and passenger's side)
new exhaust and intake valves for the heads

...I'm probably missing some things on this list. How much did you buy this car for? I would give this some though before going any further.