today i notices that when i was sitting at a drive through with my car to temp that the heater was blowing cold air but as soon as i started driving it was blowing hot air. any ideas?

 

check your coolant level, sometimes when coolant is low you will loose heat at idle and when rpm comes up heat will come back

 

i did that the radiator is full but the over flow was empty so i filled it. it helped only slightly if at all. if i rev it when im not moving then the heat comes back. the only other things i can think of are the heater core... or God forbid the water pump. any thoughts? the water pump is tight though and there is no play so the shaft bearings i would assume are good. ive never seen a water pumps impeller go bad at 100k miles on any car before but i do suppose its possible. ive also never had a heater core that went bad and didnt leak so im in new territory as for car problems. can air in the cooling systems of these cars cause this issue? i have a friend who had a similar problem with his volvo but it uses a pressurized overflow/coolant reservoir.

 

it might take a few minutes or longer of driving to get the air out of it. If you dont see any coolant on the floor or on the bottom of the engine, drive it for a day or two keeping an eye on the coolant and see what happens then, If the coolant is down again, you probably have a leak,

 

there isnt any on the floor that ive noticed yet and im pretty **** about such things. will these cars purge air in the cooling systems on there own or is there a bleeder valve that has to be opened to let the air out? i did just let it sit and idle and i felt the heater hoses and they were warm but if i bumped the throttle for a second or to i could feel almost like a gargle and the heater hoses got warmer and would cool shortly after i let the rpms drop back to idle. its also interesting to me that i can put my hand on all the radiator hoses, the radiator, intake manifold, block and valve cover with the car at temp and none of them are so hot that i have to remove my hand. is that normal? id think though if the water pump was bad id have over heating issues which i dont. the temp gauge gets to half way and sits there like a champ no matter how long it idles or even on the long road trip i took last week

 

the gurgle or noise your hearing is air in the system, there is ways to get some air out on some vehicles but you really have to be careful, if your not seeing any leaks, keep an eye on it and drive it for a couple of days, and see if that helps, there might be other problems, but this is the easiest to start with

 

have you flushed the system could be partially clogged, depends on engine if theres a bleeder valve should be on housing where upper radiator hose comes out of engine if it has one,

 

the way to bleed air out of european cars(which is what im used to driving and working on) is to open a screw valve right thats right before the thermostat when the car is close to and at temp and leave it open untill only a steady stream of coolant comes out and no air bubbles. since its not over heating ill drive it for a couple days and see whats happens. are water pumps impellers on these cars prone to failure around the 100k mile mark? mine has 103k miles on it. i know on BMW's they are a every 4 year or 40k mile replacement park. but they are also alot easier to do being rear wheel drive cars


update: i just found out from the PO that the water pump was replaced with the timing chain at 90k miles so i seriously doubt its an issue so im 95 percent certain its air in the system. what is the proper procedure to purge air from the cooling systems in these cars?

 

I have the exact same issue as you, and I have had the dealer bleed the system and it still won't heat up until I rev the engine or start moving. I will be watching to see if you find anything. I assume that it is something to do with the heater core, because my system is all new other than that.

 

I have a similar issue and was told it was possibly the thermostat sticking...so you may want to check your thermostat out since it is a relatively easy thing to do.