loosing coolant fast???

i can not top off the radiator!!! i top it off a few minutes later its down to the bottom of the filler neck, no matter how long i sit there and try to top it off its impossible. where is the coolant going???

checked the oil... no water in the oil, oil level stays right where its at

radiator dip stick... checked the stick doesn't appear to have any water in it, the level is right where it should be

exhaust... checked both exhaust tips... neither seems to have any type of water residue nor does the muffler drip nothing out of the ordinary

looked for leaks underneath the car... negative

i just replaced the thermostat with a 180 and made my own elbow out of copper for the heat exchanger tension (previous elbow was cracked), water pump was replaced 6 months ago, i just put the radiator in a couple weeks ago, cleaned it off good and checked it for cracks/damage etc... nothing at all seems to be in good condition

where can my coolant be going?

car normally runs right below the 150 mark but sometimes reaches 210 followed by the low coolant light even while driving

oddily enuff it doesn't seem to run hot when idleing, i've bleed the thermostat housing a few times and there hasn't been any air at all.

im thinking time for a pressure check but i don't want to make the problem worse if some one else may know the answer in advance... thanks

If you have a plenum leak, the coolant could be collecting in the exhaust. How much coolant have you added to try to get it full? If it's a lot, try getting the rear of the car lower than the front (park it on a hill, put it on ramps or jack the front up) and see if you get coolant out the tailpipes then.

If no external leaks its got to be going in the engine/tranmission or out the exhaust. Did you do your LIM/UIM gaskets?

thanks for the tip i'm going to go park on a hill maybe i can see something i've missed, haven't done the gaskets yet due to a lack of a torque wrench i ordered one last night off ebay so hopefully i get it in by next week so i can knock it out...

its not burning the water (visibly, no residue on my hand when i leave it there) also, all the other fluids seem to be alright... i will inspect further until i uncover the culprit thanks alot for the tips hopefully its not too bad