Replaced thermostat, but engine temp says cold while driving...

[missingwhatsnear]

I replaced my thermostat recently when my car started overheating one day. The past few days, I start the car to warm it up, then temp gauge read normal after warming up for bout 15 minutes. Then when I start driving, the temp guage slowly bogs down to cold...and stays cold while I'm driving, and warms up slowly while at a stop light. And about every other day, I have to check my coolant, sometimes end up bones dry.
Have checked under car while running and havent seen any fluid leaking on to the ground. I have also not seen any fluid on under side of hood or on engine or anything.
Anybody have any suggestions?

[crusierdad76]

from the past post that i have read it sounds like you have air in the system ,and it is causing your problem you have to some how bleed all the air out of the cooling system I know i read how to do this but since i have never had to im not 100% sure

[CREWZIN]

There's quite a few reasons why the PT overheats and apparently the thermostat wasn't your fault. If your loosing water and not seeing any drips or water around the engine it could be you have a bad head gasket which is letting tiny bits of water into the cylinder and burning it up.

Take it to a shop and have a compression test.

[quicksilverdon]

Peculiar.
When cold, take off radiator cap - is coolant up to the top?
If it were a head gasket, you'd be overheating.
You need to find where coolant is going.

[missingwhatsnear]

well me and my dad got underneath it and check where the leak was coming from. i looked like its coming from the water pump behind the black housing and the belts (including the timing belt). we had to take the wheel off and the wheel housing to find it through the pulleys and belts. sound right?

[quicksilverdon]

How many miles? If you do water pump, might as well do timing belt, too, since it same labor....