E39 Heater Not blowing hot air

[Driftit 2078]

Never checked this when I was checking out my new E39 540 to buy.

Aircon works mint. Can change where the air blows fine. And also change the fan speed fine. But changing the temp only goes from Aircon cool to blowing room temperature air. Even on full hot.

And another problem they may or may not be related. If I press the Auto buton the little light comes on but I am pretty sure it does nothing. e.g. I can change the temp to 16deg yet it still blows air at the same rate as if it was set on 25deg.

Car has done 86,000kms. Is a 1997 540i.

[jochen 4]

Connect the BMW diagnostics and it will tell you exactly what is wrong

The auto AC system is complex with lots of sensors and valves and flaps.

I would suggest the heater control valve in the coolant system is faulty, but a diagnostic check will tell for sure.

Go to an independent expert, like Glenn at Botany Motor Works.

He is excellent on all BMWs and has all the diagnostic gear to figure out the problem very quickly.

[1rotty 40]

Never checked this when I was checking out my new E39 540 to buy.

Aircon works mint. Can change where the air blows fine. And also change the fan speed fine. But changing the temp only goes from Aircon cool to blowing room temperature air. Even on full hot.

And another problem they may or may not be related. If I press the Auto buton the little light comes on but I am pretty sure it does nothing. e.g. I can change the temp to 16deg yet it still blows air at the same rate as if it was set on 25deg.

[Car has done 86,000kms. Is a 1997 540i.[/quote]

A 97 with 86ks has to be a good score.

(sorry,cant figure how you do 1 line quotes-computer d*ck LOL)

Edited March 8, 2009 by 1rotty

[Apex 693]

Is the car an import?? Drove a car without a heater once due to it being from a hot climate.

[HELLBM 1557]

Heater Control valve. One of the more common E39 issues. $350 to $400 new.

Don,t bother with second hand and make sure you get a decent scanner onto it before you commit to anything..

[Driftit 2078]

Cheers guys. Left the car in town today. Will get her scanned tomorrow at some stage.

I did scan the car before purchasing. But the only thing that came up was that the battery had recently been flat and that at some stage it has had a misfire which was no doubt due to poor gas or when the owner ran it out of gas recently. Think I must have missed it.

[kiwi535 538]

Cheers guys. Left the car in town today. Will get her scanned tomorrow at some stage.

I did scan the car before purchasing. But the only thing that came up was that the battery had recently been flat and that at some stage it has had a misfire which was no doubt due to poor gas or when the owner ran it out of gas recently. Think I must have missed it.

If it is an singapore import they sometimes have the heaters blocked off!Misfire on 540 CAN be serious.

[Driftit 2078]

If it is an singapore import they sometimes have the heaters blocked off!Misfire on 540 CAN be serious.

This car has a massive misfire problem.

http://www.trademe.co.nz/Trade-Me-Motors/C...n-205975065.htm

Mine has not done it since I owned it. So as I said. Was more likely to be poor gas or when they ran it dry.

It is a singapoked 540i. But she has been very well looked after and serviced. Full singapore history etc. Limited NZ history. Which is typical. Kiwi's never service their cars till something goes wrong.

[Driftit 2078]

Update:

Fixed the problem. Was indeed the heater valves. But all they needed was a light tap and a few cycles from hot to cold. Car has been sitting around for a while and has prob never used its heater.

Auto function works perfect too.

Though NO error codes came up while we were trying to sus this out. Strange.

[Eagle 1662]

Sounds the same the old E34