i cant get the heat to turn on in the car the air is constantly cool even hour after driving... what could be causing this?

 

How's your coolant level?

 

air in heating core. system needs burped. did you just recently flush antifreeze?

 

sounds funny but a few years ago i knocked off my small skinny rubber over flow line that connects to the top of the radiator, thus the radiator was essentially open and i had no heat until i found the small problem, LOL

 

just changed my heater core. and the box that covers it was cracked during my DIY job. so that could be causing the air in the heater core. I actaully just got back from the junk yard and found a replacement for 50 if i pull it.. So if i change that it will stop leaking cold water and the heat should work... im guessing?

 

leaking cold water?

More like, theres a bubble in your system - likely in the core - that needs to be burped out.

 

The cold water that is coming from the box you cracked is most likely condensate from running the a/c, and not water from your cooling system. You want to get that taken care of unless it is dripping out under the car which is totally normal.

Like other people have said you have air in the cooling system. It automatically bleeds yourself all you need to do is drive it around until it is warm with the heater running then park it, let it cool a bit, and top of the radiator. repeat this until the fluid level doesn't change

 

Unfortunately winter is starting to head this way and I'm having a similar problem. The heater will only be warm if the car is moving. Once I stop the air blowing in is cold. Is this the same type of problem that can be fixed with the coolant or is there something else I'm missing.

 

Nope, same problem. You have air in your system, a leak, or something of the sort.

 

is it true that you can't put water in the overflow tank? i noticed that my coolant is low and somebody told me to pour some water in the tank so it could mix with the coolant.

 

no and no, go to the auto store and get the 50/50 mix and fill up your radiator then add a little bit to the overflow tank

 

Add some coolant to the radiator to see if it helps your problem, if not then you have air in your system or a crack in the blower housing somewhere

 

You can. A small amount of water will not dilute the coolant mixing ratio significantly. If you have to replenish the reservoir on a regular basis, then you have a problem. But, why not add coolant instead of water?

 

So the best way to get air out of the system is to drive it around the block a few times, fill up the coolant, drive it some more and fill again if necessary? That sound right.

 

50/50 mix of antifreeze is, well... a bad purchase. It usually cost the same if not more than straight antifreeze. You understand you are paying for half a gallon of water, right? at like $5.00 for a gallon of water???? Get the straight and mix it yourself.

 

True, if you are adding constantly you have a problem. But I wouldn't recommend to constantly add coolant, if you are adding it all the time, because you don't want a system full of coolant and no water. It needs to have a nice mix of both. Just wanting all to understand that having straight coolant in the system is not good advice.

 

50/50 mix is what you want to have in there. Coolant is anti-freeze, doesn't work as well for high temperatures. The water is there for the higher temperatures, but doesn't work well for low-temps. Hence the 50/50.

If you're using PURE coolant, you should mix 50% with distilled water.

Or, you could just buy the premixed 50/50 stuff and pour it in all day and all night.

 

Reminds me of my IM & head gasket failures on my old GM 3.1L engine; I always used to add 100% anti-freeze...because I didn't know any better.

 

The overflow port you are referring to is only literally open if your car is overheating causing pressure valve in the radiator cap to lift up opening port so excess pressure can bleed off. There is NO WAY air could go in to that valve because the silly little hose to overflow tank fell off. Come on.....

 

The overflow tank is just that An OVERFLOW tank. When car overheats or builds up too much pressure, the pressure valve in radiator cap opens to allow system to bleed off excess pressure. There is no mechanism to allow coolant to move up from the overflow tank through closed valve back to coolant system. You only add coolant to radiator and it's best to do that with engine running to properly top it off.

 

the over flow tank is more than just an overflow tank. if all your hoses are free of leaks and the system is air tight the overflow tank will self bleed the system.

as the engine and cooling system gets up to temperature the pressure raises and will force air and coolant through the radiator cap to the overflow tank bleeding the system of air. as your engine starts to fully cool the cooling system pressure lowers and sucks back in coolant from the overflow tank and replaces the volume of air that was pushed out with coolant.

I drain and fill my radiator every year to keep the coolant fresh and I never burp the cooling system. I just keep adding coolant to the over flow tank. after all the air is bled out the overflow tank level will stop going down when the engine fully cools..

to help it bleed better while the engine is cooling off I turn the heat on before I shut the engine off.