Changed heater core, now new problem

[gainman]

92 GTZ Quad 4 5 Speed

Heater core blew out on the gtz.  I replaced the heater core and hooked everything under the dash back up and no fluid leaking.

I pulled it out on the driveway and let it idle for a while to let the motor warm up so I could test the heat and I went inside.  When I came back out a few minutes later, there was white smoke coming from the exhaust.  I shut the car down and checked all the fluids, and everything looks good.  I fired the car back up and the smoke is even worst, and it smells really strong of exhaust, and a hint of engine coolant.  The gauges look perfect, the motor runs like a top, and nothing else looks out of the ordinary.  

What am I in for, head gasket?  Is it toast?

Side note:

Check engine light is on, coolant temp sensor code active.  I see a sensor broke off from the block under the master cylinder.

[Money pit Beretta]

Sorry man, I don't know much about the Q4. My guess is that the coolant temp sensor is what is broken(bet you know that). On the V6, the intake gaskets can leak coolant and cause some smoke. That would be a cheap fix,but if that's not it, well it could be the head gasket.

[gainman]

my guess is head gasket.  the smoke is pretty thick coming out.  the coolant temp sensor would not cause smoke to come out of the exhaust, though it is broken.  I am just trying to get some insight before i decide to fix it or sell it.

[Money pit Beretta]

The smoke is that bad? Yea, it would have to be the head gasket. The broken coolant temp sensor = the code(as you know) that is what I was trying to say(guess it came out wrong). On selling the car: what you have is kinda rare these days.

[gainman]

yeah, thats going into consideration also.  to add to the rareness, its quasar blue.

needs some work though to be top notch.  ran like an absolute champ, but needs a headliner and some paint.  and the rims are hurting too.

[Money pit Beretta]

Small stuff man! I know, there will be more things to repair later down the road, but that's the way it goes. Quasar Blue, did you ever post any pics??? Man, I just got my 95 in spring and I dumped 2K into it so far. I would bet yours is in better shape.