When my car is idling, the heater blows cold air.?

Question

As soon as I get moving or rev the engine, it immediately goes back to blowing hot air. I had the problem last year and my mechanic said there was an air bubble? somewhere and he put it up on some sort of lift that could tilt that is for truck work and somehow got it out. Whatever he did, it worked and now it's doing it again and the same thing is happening in our other vechicle!!! When the problem happened last year, 2 other mechanics, previous to ours (Dealers!) said it was fixed and it wasn't and cost me almost $300. When our mechanic finally got a hold of it, he charged me just for his time and it WAS fixed, until recently. What the heck are we doing wrong? I have never had this happen with any of the many vehicles we have owned, new or used, in my life!! The vehicle that has and once again is giving us the problem is 10 years old but the other vehicle that has just started doing the same thing is under a year old. What the heck is going on?

Answer 1

BOTH cars?? that seems to discount the water pump (or impellers in pump)
Which leaves us to low antifreeze/water level which recurs (ok then goes bad)
now we are talking water leak or USE. Volumes of white steam out exhaust are headgasket/cracked head. MOST LIKELY you have a small leak or bad
radiator cap or just didn't fill it properly in the first place. While engine is COLD
remove the radiator cap and look at fluid level, then start engine and look, then have husband watch fluid level as you give it some gas. You'll notice a rise and this is when the fluid is going to flow thru your heater. Let engine idle and add 50/50 antifreeze/water to about 1.5" below fill neck while car warms.
If over a little it's ok as it will enter overflow. have hubby continue to monitor level at idle until car is warm. [Add fluid ONLY as needed to keep 1.5" below neck]. Engine warm? Turn on heater - nice, huh? Yeah. Put on radiator cap
securely! check overflow tank at least to warm level. Do BOTH cars.
Look for leaks at idle and after parking. Look for lost fluid from OVERFLOW
TANK. Use cars awhile. If problem returns -- replace cap on radiator, but
REPEAT THE PROCESS to get correct fluid level. don't gripe about cost of antifreeze as those hijackers are not getting paid for maintenance.
THEY should have already checked and replaced radiator hoses, but check again AND LOOK AT EDGES AND BOTTOM OF RADIATORS FOR TRACES
OF SEEPAGE: if leaking -- go to autoparts and get ONLY the powdered
aluminum [NO OTHER PRODUCT]and add to radiator [1 each as directed] then drive as directed.
You should have replaced leaking hoses. check around base of thermostat for seepage.
Now LAST item: email me (lol) I'll send a Grand Dad bill....(lol)
If this fixes your car -- NEVER go to those mechanics again and tell your friends... or just forgive them. God Bless, Greg

Answer 2

You could be low on coolant because of a leak. You may have a leak in the head gasket allowing combustion gases to blow into the water jacket, probably not your problem. It sounds more like you have a restriction in the heater cor or maybe a water pump problem. I would check (or have someone check) the flow through the heater core first.
The water pump idea has to do with being able to move the coolant effectively. If the impeller (blades) rot away, it will not pump good. Seen it happen a couple of times. You did not give any vehicle details so I cannot give anything more specific.

Answer 3

Car Charger Heater

Answer 4

replace coolant hose out system for 15 minutes that should clear blockage in cooling system .also get the oil leak sorted too little oil car will overheat as well ok. engine heating due to low oil ok . fan coming in at idle proves point is coolant up to level easy to check pump water that is bearing could be gone there ok all the best .ps rem to replace 50 to 50 coolant and anti freeze .

Answer 5

I doubt if you would br using water and no antifreeze this time of year or that you would have a week water pump on both cars on idel your car runs hotter but the water does not circulate as well and will not flow through heater core as well an air pocket or bubble would cause this try more antifreeze ie higher boiling point

Answer 6

I have the same problem with my 2005 Jeep Liberty....I just had it serviced had a recall issue dealt with; hitch installed to protect from back-end collisions... I had to oil changed and transmission tray and filter replacement etc...I mentioned to the mechanic about the heater only working when car is moving he said I'd have to pay additional 150. to only diagnose the problem....lol.....any ideas...I love my car I want it fixed without having to sell a kidney to cover the costs!! lol

Answer 7

i own a repair shop,and you need to check the coolant level in it,when they get so low they wont blow a real good heat at an idle ,you have to be moving so the coolant is circulating real good,but check that i think that will be your problem with it,good luck i hope this help,s.,,PS you also need to find a different mechanic or at least an honest one,good luck.

Answer 8

You're low on coolant.

Answer 9

your low on coolant............fill your reservoir to slightly over half....drive for a while....till you reach operating temperature.....then check the reservoir......add if needed........if this dosent work .....have your system pressure tested at the nearest radiator shop.....most cooling system,s will purge themself,s of air.....as long as there is no leak.....hope this help,s.........good luck!