good question?

[eazy02909]

the heater does not work on my 325is 94 until i drive the car. WHY? any clues

[Waveho]

There is a valve connecting a hose running from your radiator to your heater core. This control valve (I don't know what the official part name is; I'm sure others on this site can help with that) is subject to blockage; I would bet that this is your problem, assuming you are still blowing air through your vents. If your heater core is still good (you'd probably know by now), then it may be as simple as either cleaning or replacing this valve. The valve costs around $200 if needed new. As always, check your fuses and relays first! You'd be surprised at how many big-seeming problems can be resolved by replacing a bad fuse, if something just seems to not be working properly.

[AW328i]

Have you checked your coolant level? Also you may have a bad thermostat.

[JBlood]

Maybe I'm not understanding the question, but I don't know of any cars that put out heat unless the engine is running and warm.... the heater core needs hot coolant from the radiator to warm the interior. Now if the fan doesn't work properly, then both of the above responses should get you pointed in the right direction.... :)

[Waveho]

I understood the question being that the heat does not work AT ALL unless the car is in drive, where it then begins to heat. This would indicate a fluid flow problem, related either to the thermostat or control valve, or some other blockage along the way. But.... You are absolutely right in that the car must be running--I didn't read the query that way but now on re-read I'm not so sure!

[eazy02909]

thanx guyz - i think it is the valves because the thermostat is new and the radiator with all the hoes are also new. i did all the work myself months ago.another problem is that my computer says coolant low only when im about to turn on the car and when i shut it off but when i press check it comes off. i fix that problem last time by taking off the screw next to the coolant bottle. i think but im not sure its call bleedin the system

[BMWredneck]

well my car blows normal air until i start driving it, all the cars ive ovwen have been like that. The heat doesnt normaly start blowing right off the bat, and if it was blockage, why would it start working after he puts it in drive? Wouldnt it just stay blocked. And if the pressure breaks it loose why would it happen every time?

[Andycapps]

Hey I have a 94 325is, and I am having the same problem with the heat. It only blows hot when it gets to going down the road/moving. Even when the engine is at Normal Operating Temp. it wont blow warm until I start moving.I replaced 80% of the entire cooling system about 2k mi ago,well everything but the heater core and the Heater flow control valve. I used a BG coolant flush machine to flush the system and I've Tried to bleed it several times. So anyways, I havent figured out the problem yet. It very well could be a bad Valve, or it could also be a big ass Air pocket that doesnt wanna bleed out,but I want to make sure before I spend another $200 and the heat still not work. One thing I dont get about the "Bleeding procedure", I've read that you have to Have the car in the 'ON' Position wit the Heater on, and the Cap off with the bleed screw open. It says to Fill it up to 'Kalt'/cold until nothing but coolant comes out the bleed screw hole. YEah i wish it'd work as easy as it sounds, but I never get coolant to come out without constantly opening/closing the screw while sqeezing the upper rad. hose. At that I still dont get how this is suppose to work. Anyone have any tips/pointers about bleeding all the air out? It seems to be a P.I.T.A.

[Waveho]

It will warm up slower while idling but every car should still start blowing warm without the need to be in drive. I still think the problem is with the flow control valve--Only thing I can think of that it only heats when in drive is that there is generated more pressure and the fluid is able to either flow through some blockage or through the failing flow control valve. The valve was an issue with a different vehicle I owned earlier (good air flow but variable heating) and replacement did the trick.