hoyleyboyley

had my a/c regassed, new compressor, fan etc in the summer (to the tune of £500) all good - air is ICEY cold. 8-)
thing is, now the weather taken a turn, if i turn the heat on both sides up to max (28°) it doesnt seem to get that hot... now it wasnt uncomfortably cold in the car (3° external), but TBH i'd expect the air coming out the vents to feel warm/hot.
anything it could be?

ta

M540i LE

make sure the wheel in the middle of the 2 central air vents is turned to maximum red.

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hoyleyboyley

dont have that setup for air, have got the dual controls:

M540i LE

Above the radio - the 2 vents - there should be a wheel between them. I find that if this is on cold, it doesn't matter what temp it is set on.

Wane Ramsay

In the middle of the top air vent(the one just above the computer/radio)there's a knurled wheel that controls the temp to face vents. turn it towards the red marking and that should do it.I think thats what M40i LE meant.
Wane.

hoyleyboyley

aah - understood. did try this, but no effect.

got this reply on another bm forum

"This would normaly be either the thermostat or, more likely and air lock, which seems to be a problem on most 5 series at some time or other.

Bleed he system by getting up to running temp and opening the bleed screw near the filler cap, taking care as it is all very hot (105c) and let the air fizz out. It may help to jack the offside front up (use the jacking point only) to raise the filler to be the highest point, so it helps the air to escape. Give her a few 3000rpm 30 sec revs and then close the bleed screw down. Check the coolant level when it's cooled right down, which can take a few hours, then you should get toasty warm "

cheers.

M540i LE

Ah well...I was hoping for your sake it was something simple. Good luck with the bleed!

milesr3

I wouldn't do this if I were you. The valve on the coolant expansion tank near the filler cap isn't a bleed screw and doing the above will simply de-pressurise you cooling system, which isn't good.

The bleed screw is in one of the hoses connected to the heater solenoids by the bulkhead. It would be worth checking the two bleed hoses (one from radiator, one from temp sensor manifold) for flow into the coolant expansion tank by looking inside the expansion tank at fast idle with the engine cold. Replace the cap before it warms up too much - or at least remove and replace the cap when it is stone cold to allow it to repressurise when it warms up again.

You could then check the hoses into the heater control solenoids at the bulkead to see if they are warm and bleed air out of the bleed valve here if necessary. Set the heater controls to maximum.

If warm water is getting to the heater matrix, but warm air isn't coming out then it could well be electrical. You have climate control as I do and mine seems to have mind of its own sometimes, although more with the fan speed than the temperature and which vents the air comes out of. Could also be that your heater matrix is blocked, or the control solenoids have got stuck if it's been shut off (full cold) over the summer.

HTH
Richard

p.s. mine still blows cold(er) air out of the face vents regardless of whether the knurled wheel is set to red or blue. It isn't noticeable at first when the car is warming up as the 'auto' setting on the distribution blows warm air firstly to the screen and then to the feet as the car warms up, then when it has reached the desired temperature, it decides to let some air out of the face vents, which in my car always seem cold or at least colder than the other vents. I tend to close them because of this.

Simonal

Ok one other problem could be the well known Microfilter replacement.

Although it may not sound like it the fan could be struggling to provide the full power and thus the full heat.

This was the cause of my heating failure last year after changing the filter all was well this needs to be done at least twice a year to provide the best performance.

Often this is the cause of the heating failure and since this is a reletavely easy fix that can be carried out at home there are instructions on the board try searching for "microfilter"

Hope this helps.

PS as for the central tempreture wheel in the centre air vent I find this works independantly so you can adjust the tempreture regardless of the heating controls so in summer you can provide warmer air to head even with the A/c on and the tempreture on cool.