What the heck is wrong with my car???
 

Everyone I have talked to is completely stumped. Maybe someone on here has dealt with a similar issue.

My 1990 300ZX twin turbo runs great, but it overheats and sometimes the heater wont blow hot air. I can't get water to circulate in the engine. Decided to try replacing the thermostat and water pump. In the process, found that nothing was wrong with the water pump and that the car did not have a thermostat at all. There are signs that the water is going somewhere, we just can't figure out where it's going. No water in the oil, no steam coming out of the tail pipe, but there have been times when the car left a trail of water behind it, so we know it's leaking somewhere. Does this sound like something that a new thermostat could fix? Does it sound like a head gasket? We're stumped!

When the car is still cold right? That's from the cat warming up. If the motor was sucking in and spitting out that much water, it would have hydro-locked. :D

So you tore apart the thermostat housing and didn't install a thermostat?

How far did the temp needle go when it overheated? How long did you drive it after that? How many times has it done this?

A clue!

If it were a HG you would be blowing lots of white smoke and it would give off a sweet smell. But I am going to quote NismoPick for my next question: "So you tore apart the thermostat housing and didn't install a thermostat?"

We are in the process of installing a thermostat. I was describing what was going on before we took it apart to replace the water pump and thermostat.

We also found that the timing belt needed replacing. Working on all of that now. I just wanted to see what suggestions anyone on here could offer.