94 540 AC not cold till 1 mile down the road

[silverz06vette]

Start out after the car has sat overnight or the day at work. The AC does not blow cold till I get .5-1 mile down the road, then its nice and cold.

No work on the AC system since we bought the car at 99k. Car now at 160k.

Thanks!

[Phil M]

thats pretty normal. mines the same. you have to give it a lil time to get going, as on most cars. mines not as cold as it gets til its completely warmed up.

[silverz06vette]

You can sit at idle for a while and it will not get cold. Seems like it was not that way before. Got her up for sale and its going to fun to convince people that is normal when its 98 million degrees here in Atlanta. :)

[Phil M]

Also you can sit at idle with it on "4" and watch your temp guage go thru the roof. :P I'm not sure but I would suspect that it has to do with the engine getting up to temperature for it to be going strong. same way with the heat in the winter i'd say. someone please correct me.

just drive her around a bit before someone comes to look at it..

[silverz06vette]

Thanks! I will do that for sure.

[JonE]

could it be a problem with your auxiliary fan? or a bit low on 134a?

[silverz06vette]

How do it check the aux fan?

Thanks!

[JonE]

On my 535i it is the thinner fan right in front of the radiator, I can see it from the front of the car. It's supposed to come on when AC switch is on or when car is starting to overheat. It has two speeds; low kicks in with AC switch or when temp needle is between 1/2 and 3/4, high comes on when temp. guage is going 3/4 or higher. Not sure if the same as your car, though.
Usually if the aux. fan only works on high then it might be a resistor's bad.

[TimGinCentralNJ]

...I never had any idea how having a large volume of air moving across your radiator and evaporator plays such a huge part in both your A/C system pressure, and it's cabin cooling abilities. The difference in cabin temps sitting at idle (73 degree, low humidity) with an ok fan clutch and good aux fan versus driving 35+ mph was upwards of 35 degrees difference in cabin temp during my test. Guess who's got a new fan clutch on order!

Make no mistake, I'm just a hack mechanic wanna-be, but it strikes me (especially for my R134a retro A/C) that these cars were probably not originally designed with a sunny Atlanta day in mind as far as their A/C was concerned, but I'm thinking your A/C should still be able to keep you cool even in traffic as long as it's functioning properly.

Rgds,
Tim G
'91 535iM w/ "not ready for prime-time yet" A/C


Also you can sit at idle with it on "4" and watch your temp guage go thru the roof. :P I'm not sure but I would suspect that it has to do with the engine getting up to temperature for it to be going strong. same way with the heat in the winter i'd say. someone please correct me.

just drive her around a bit before someone comes to look at it..

[Tiger]

You probably just need some R134a top up... You probably just lost a bit of freon.

[krisby]

I would have thought a mile to get up to temp is good. Surely its like a fridge isn't it? you adjust the temp but it does not drop immediately, or with an oven, you turn it up and the heat does not magically jump to your new temp.

I know my 525 and Diamante both need some time for the AC to start pumping out cold air, and likewise in winter for hot air to start blowing. If I turn auto on it does not automatically increase the fan speed until the engine is up to temp.

But then i could be wrong about your car, did it used to blow cold air immediately? Or have you only just noticed on a particularly hot day that it takes a wee while?