A/C & Heater Blower Issues - Please Help

iwantbmwm3 · 04-21-2010, 07:46 AM

Hey guys. I have a 97 328i, 5spd, 155k miles.

I have searched. But could not find a definite answer.

So my heater and ac doesnt blow very hard. It blows when im driving. According to other posts, its the heater core valve?

Also, another thing. I have a newer (March '09) waterpump, thermostat, housing. when the car is turned on, and the coolant resovoir cap is off, there is no circulation of coolant at idle or lower rpms. Circulation of coolant happens at higher rpms.

In the other posts, people suggested putting in new water pumps, but mine is new. (no overheating issues or anything).

since i know this issue of no circulation of coolant, im assuming thats why i have no ac/heater unless im driving.

What do you guys think?

i really need opinions/suggestions.

Wapiennik · 04-21-2010, 09:07 AM

Quote:

Originally Posted by iwantbmwm3

So my heater and ac doesnt blow very hard. It blows when im driving.

Hello Sir,

I'm somewhat familiar with most of these parts, but perhaps it's something a little more simple? When you're driving you feel the air, at idle you don't. More than likely your cabin air filter is probably completely clogged with road debris. Replacement is cheap and quick. This would make sense that you start to feel the air when driving when the wind current from the cars momentum becomes pushing against your clogged filter.

As for your heater, at 155,000 miles and it being a thirteen year old car it's probably just do for a very good coolant flush.

Hope this helps in any way.

iwantbmwm3 · 04-21-2010, 11:22 AM

Hi, thanks for the reply

however, i put in a new cabin filter as well when i put in the water pump and all that. and i have had a coolant flush as well when i replaced the other cooling parts.

any other ideas? anybody thinks this could be a faulty/clogged heater core valve?

also any reason for the poor circulation of coolant at idle in the expansion tank?

Wapiennik · 04-21-2010, 06:44 PM

Well it's possible, but if your a/c doesn't work either that's odd.

If I had the time and it was my problem I would be tempted to remove the dash and see if your fan motors that control vent opening and closing are all working properly.

As for your poor circulation of coolant, what are you doing to test this theory? If it is true, there's obviously some kind of gunk clogging your line and allowing very little coolant to pass. Definitely look into this, as improper cooling could cost your over a thousand dollars down the road when your head gasket takes a ****.

Keep us updated with any of your findings.

iwantbmwm3 · 04-22-2010, 04:11 AM

i dont know if its the fan motors because i can hear the fan getting louder as i increase the speed, its just the amount of air coming out. When i am driving at higher speeds ~40-45+ it blows fine. Its just at idle and lower speeds when there is very minimal air. The defrost works fine and blows air.

as for the circulation, when i had my waterpump, tstat, etc changed, my friend who changed all this for me, was pouring in coolant with the car on and noticed there was no coolant circulation at idle (no coolant from the top skinny hose on the expansion tank being poured back into the tank), when the engine was revved, the circulation of coolant was better.

Wapiennik · 04-22-2010, 05:42 AM

What I meant by fan motors is a bit different than blower motor. There are little tiny electrical motors the size of a silver dollar that respond to your climate control unit and open and close vents depending on your selection. The defrost motors are different than the main vent motors, and the floor vents, etc.

If these little motors go out, they might be inconsistent at properly opening your vents.