ok i installed a new thermostat on my bro's v6, with a collant flush and also a new seal on the thermostat. well after i got it in the car would overheat, go all the way up to the H on the temp guage, sounded like a bad thermostat, went to autozone, and traded it in for a different one, they just traded em for me, nice guys, and so i put that one in and it works like a cahrm, except this morn, i let it run for about 20 min, (it -10 degrees up here), and the engine warmed up to where it was supposed to be, awesome, but nowim not getting any heat, if i rev the engine up to above 2000 rpms it starts givin out heat, but at idle it gives me nothing, PLEASE HELP!!! heat is nice in the winter and i dont want to be going without any.

 

is the control valve working?....did you put in the right mixture of antifreeze?...is the rad frooze up?...what degree stat in car?....

 

Since you didnt mention this ive got to ask. When you where ready to fire it up did you remove the radiator cap and let the engine warm up while it was burping air, continueing to fill the radiator? I think air lock is something people overlook when they open the cooling system. The level probably remains the same until the thermostat opens.

 

as far as i know, the temp said 88 degrees celsius, i think, so 180 degree stat? maybe but neways, i know the antifreeze is flowing cuz i drove it today and the air is hot when im driving it, so i know its working, the car doesnt overheat like it did before, but when im at a stop, it takes a min, but then it blows cold air, not freexing cold but not warm by any means, yes i did add the correct mix of coolant, and i let it run for about 15 min with the cap off slowly adding coolant and letting the air out, im positive i did everything right, but why would it not blow cold air at idle, when warmed up? i got home after running around for about 30 min, got home popped the hood, felt the radiator hose and very warm, good i know coolant is flowing, and that it is warm, it was still running mind u, and then i went back into the car to trun it off and there was cold air blowing, i revved it to 2 grand and wasrm air came out, then i let off and it got cold again. im completely lost

 

control valve or a vacuum problem with the controls