Why Is The Heaters In My Car Blowing Out Cold Air & Not Heat?

Now that the cold weather is among us, we'll be whacking the cars heaters on the second we've turned the key. Car heaters work by using the heat in the water sytem that helps cools our cars engine, so you won't get heat untill the car has been running for a couple of minutes. A thermostat regulates water circulating around the engine until it reaches a certain tempreature and then lets the water circulate to let the coolant cool your engine. If you cant get heat no matter how long you leave the car running im going to show you some checks you can do to find the culprit. If you're don't mind getting stuck in then you can complete most of these jobs with a good Socket Set.

 As your heaters run off the heat from the water/coolant the first thing you should check is to see if there is any coolant in your engine you can do this by lifting the bonnet and looking at the header tank this is a ( Large ) clear tank with usually a yellow cap with rubber hoses coming off of it and is usually situated at the sides directly above the wheels. You will see on the side Max and Min Markers if this is empty then fill it back up with ordinary water, you can add some anti freeze. If your header is full then proceed to the next step. If you are not certain which is your header tank ask a freind or take to local garage.

As mentioned before the thermostat is what stops the water circulating around the engine preventing the engine being cooled on initial start up. This the heats up the water that your heaters get their heat from. So if you have water/coolant in the engine, then a broken thermostat may be the culprit. Leave your engine running and take a look at your dials inside the car, there will be one that indicates water tempreature. It can take a while for a working thermostat to even start to show a reading so give it about 10 minutes to be warm enough to give a reading. If your engine is hot but you're not getting a tempreature reading on your dial, then a thermostat is the reason why you're not getting heat from your heaters.

 If your car has lost water and loses water then you to find the source it can be a split hose leaky radiator or even worse headgasket. Sometimes a cause for a loss of water or loss of heat is a knackered water pump a tell tail sign of a broken water pump is a constant rough metallic sound when the engine is running. Now if you're not mechanically minded then you won't be able to tell but if you plan on taking the car to a garage ask them to check that ( try take your car to a honest reputable one ) Water pumps are vital part of the engine and need to be chaned asap if theyre broken. Alot of them run off the cambelt and if the water pump destroys itself it will take the cambelt and engine with it.

Sometimes even with water, a working thermostat and water pump you can still get no heat. This can be caused by an air lock in the system. To release a air lock in your cooling system is to run the engine untill the fan kicks in. Once your fan has come on, look around the radiator for a bleed port. This is something that can be turned with a screwdriver. Once you turn it anti clockwise you should get a large hissing this is the air being released.

An engine losing water is a big problem. Finding the leak can be a pain in the butt to as a tiny little hole can empty your sytem when its under pressure when driving. If the weather is cold then your chances of finding is easier. Leave the engine so that is hot make sure you've have topped to the coolant up. Once the engine is hot, the leaking water will hit the atmosphere and turn into steam due to the cold weather. look along the hoses, where the water pump is, along the radiator and also look inside your car. If your windows steam up or your carpet inside your car gets wet then your leak is possible inside the car behind the dashboard this can be the heater matrix or split hose.

You can buy products that will stop leaks in a car cooling system saving you money on buying a radiator (If thats where the leak is ) You can also buy a repair bandage for leaking hoses but this is a temporary measure. For leaky water pumps though, you have to change them.