Quote:
Originally Posted by steel609
Might as well add me to this list. Exact same symptoms. [Actually, YOU are the first poster to this thread this year who DESCRIBED his symptoms (other than warm air instead of cool ;-)]
Driving on interstate I get nice cold air. stop for any period of time and air gets warmer and warmer. Revving engine to around 2000 rpm's does make air a little cooler, but not really cold.
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WHAT Diagnostic Equipment/Software do you have access to (INPA, Scan Tool, etc.)?
Do you have Manifold Gauges?
Do you have the time/interest to diagnose the system yourself?
There are MANY reasons why the refrigeration system (Compressor PUMPING R-134a through the Condenser, Expansion Valve, Evaporator and back to Compressor) may NOT function correctly, or air coming from vents may get warmer when you slow or stop.
You, or whoever is going to properly diagnose your issue, need to understand how the system works and have proper equipment/software to read or observe Parameters/ values such as Refrigerant Pressure, Evaporator Temp, Mixed Air Flap Positions, Radiator Fan Speed, Coolant Temp, etc.
INPA or similar Software or Scan Tool can do that, or you can monitor High Side & Low Side Pressure in Refrigeration System with Manifold Gauges. If you have, or want to obtain, any of those tools, I can walk you through tests you can do to try to identify the cause of your issue. Otherwise, simply take the vehicle to any decent A/C shop, as simply trying to replace whatever part someone tells you "fixed" his issue, when NEITHER of you understand the system or how to diagnose it, is a fool's errand.
The 1st suspect (ONLY the first -- there ARE others ;-) when the A/C system cools properly at highway speed, but warms a LOT when slowing or standing still, is Air Flow through Condenser mounted in front of Radiator, due to Radiator Fan or E-Fan NOT running fast enough. There are different things that can cause that, from issues in various sensor wiring/connectors, etc. which tell the DME when/ how fast to run the E-Fan (such as Engine Coolant Temp Sensor or Refrigerant Pressure Sensor), to E-Fan wiring/connectors or the Integral Fan Control itself.
So FIRST, determine at what % of Maximum Speed your E-Fan is operating when A/C is on at idle. If you have NEVER paid much attention to your E-Fan and the noise it makes, trying to GUESS what speed it is running at is NOT a good idea. Proper Software such as INPA, or Scan Tool, connected to your OBD II Socket, can tell you precisely what that speed is.
If you have INPA, or any BMW-specific Software or Scan Tool that can to Activation of the Fan, or monitor actual E-Fan speed while monitoring Coolant Temp, you can get a good idea of whether or not your E-Fan is operating properly, or whether slow speed is causing your "warm vent air" issue. HINT: the E-Fan is responsible for Heat Transfer via rate of air flow through BOTH the Condenser & Radiator, when vehicle stationary. Just monitor E-Fan speed with engine idling and A/C on MAX.
If you want to try to do an "initial diagnosis" yourself, just of fan operation, let me know & I'll suggest some first steps. Otherwise, find a competent A/C shop.
George