Air con blowing warm air, radiator fan not spinning?

M

MrPT

Veteran
 Bucks/Oxon
Site Supporter
All too predictably, the sun is now blazing and my air con is kaput. Vents are blowing warm air, even with “maximum snowflake”.

Initially I thought it just needed a re-gas, but this failed to fix it (or find any leaks). The a/c blew nice and cool immediately after the service, but upon heading out a few days later, things got sweaty again. I have also noticed that the radiator fan isn’t coming on under any condition now, which may be related. I usually keep the climate control on “auto” all year round, so couldn’t say when the a/c stopped working. Probably only in the past 6 months.

This is what I’ve tried, so far:

* Re-gas - improved things only for a short time (haven’t checked a/c pressure in INPA yet)
* Visually inspected compressor - the pulley spins when a/c is enabled and stops when it is turned off, which I assume this means the clutch is working?
* Visually checked for leaks
* Removed and inspected fan connector at fan pack end (not traced green cable back to DME yet)
* Checked for dip in revs when a/c engages - none
* Checked fan rotor spins freely
* Checked a/c light comes on

Is there some kind of failsafe that disables a/c if the fan isn’t working? If so, does it make sense that the clutch engages but the compressor doesn’t load the engine in any way? I’m open to the idea of a fan pack failure, it’s just going to be a hard pill to swallow since I just sold a new, spare fan pack that I’d been unable to shift for years. :cry:
 
Take the plastic cover over the radiator off. Look at the power connector for the fan, two thick wires and one thin green one. Willing to bet the green one has disintegrated.

Done dozens of them, it's the fan speed sense signal.

Let me know...

Mike
 
I’ve checked that (see my list). It’s in really good condition.

Will remove the fan pack and take a look at all the bits of the loom I can see. Thanks.
 
If a regas temporarily solved the problem, I can’t help thinking you have lost all the coolant again. They usually add a dye when the refill which shows up under ultraviolet light. Have they / you had a good look around with a uv lamp?
 
Took the fan pack out completely. It's like new.

ph001 said:
If a regas temporarily solved the problem, I can’t help thinking you have lost all the coolant again. They usually add a dye when the refill which shows up under ultraviolet light. Have they / you had a good look around with a uv lamp?
Click to expand...

That's what I keep coming back too as well, but there was a vacuum test cycle on the machine and that showed no issues. It was Kwik-fit though - wouldn't normally go there but I thought WTH for a £40 air-con recharge! They have an A/C guarantee (and the owner was great, to be fair), so will probably speak to them re. a refund if I don't get anywhere.

I'll get INPA working and see if I can check the pressure or force the fan to come on.
 
Problem on my daughters 1 series was real simple. Local garage went through all the usual, regassed, replaced sensors and alllmsorts. No difference and never charged her
We went to BMW and inminutes they diagnosed that the main engine cooling fan not functioning which stops the air on working. New fan motor unit and all fixed (for near £500...)
 
I have the same problem 2003 3.0 with just 17k miles...Just started blowing only warm air...My local repair shop wanted $1200.00 just to look at it...Told me if I got to warm to put the top down!...Now my former repair shop
 
How are you sure the fan does not come on under any circumstance - do you mean no cooling engine when hot ? ie running idle, revving, does the needle go past middle with no fan ? Thats how I knew the fan was dead, and it takes a while to heat past middle, these engines are very well designed

I think if compressor fires then there is some pressure, but just looks like you have too little gas to cool well, so a leak. I am not sure no fan means no air con, if compressor turns the DME must think all is good. My money is on the wiring which was my problem

The green wire 'looked' ok on mine, but when i started to scrape the wire to find copper to measure voltage it turned to dust, literally, no cooper at all. So I went back into the loom, cut wire, found copper, separated the fan terminals and then just used 3 croc leads to jump all pins and the exposed open green wire. Then it worked to cool engine

Its worth getting the INPA, just £35, as you can test the fan directly, it allows you to fire in a 15, 50, 90% speed signal. It wont tell you if motor or wire, but does allow you to know the signal is being sent and for you to investigate.
 
Finally got round to looking at this. I'm using INPA (not "INPA old", which seems to only provide DME info in German) from the Cable-Shack software bundle. I have then switchable D-CAN cable in "K" mode. I've posted a few screens below in case it's useful for others in the future.

Fan test

1. After selecting "E85 E86 - Z4" from the main menu, go into the "Engine" section and choose mss70 for S54

2. Choose "Actuator activations 1" then "E-fan"
inpa01.PNG
inpa02.PNG

3. Select F1-F3 to test the fan. It will be very noticeable without the engine running - 90% will have the neighbours turning their heads!
inpa03.PNG

Air con test

1. After selecting "E85 E86 - Z4" from the main menu, go into the "Body" section and choose Air conditioning
inpa04.PNG

2. Then choose "Read status", which will then allow you to view the diagnostic info in "Analog input", "Control values" and "I/O status"
inpa05.PNG
inpa06.PNG
inpa07.PNG
inpa08.PNG
inpa09.PNG
 
So, with no error codes and all switch gear, sensors and the fan working, the below is my issue, right? Low refrigerant pressure, despite passing a leak test at the garage. :?

inpa07.PNG

Any idea what it should be under normal operation? Not 1.2bar, I'm guessing!
 
It may be the actual schrader valves, we had a car in today which had that issue. Then again it wouldn't hold the gas in if one of them were gone. Worth changing both if you've tried everything else?
 
My car did this on Monday. I had a quite uncomfortable 5am start/2hr drive with the roof down it was so hot. Did some searches and one post said to start engine, switch of auto and turn the temp control all the way up and down a few times. I did it with the fan knob too... and the bloody thing started working perfectly again. I have no idea if it’s actually fixed though, so it’s still going to my indie tomorrow for a check up.
 
Bing said:
I had a quite uncomfortable 5am start/2hr drive with the roof down it was so hot.
Click to expand...

That sounds like fun. :D

Motorway though, I’m guessing?
 
MrPT said:
Bing said:
I had a quite uncomfortable 5am start/2hr drive with the roof down it was so hot.
Click to expand...

That sounds like fun. :D

Motorway though, I’m guessing?
Click to expand...

Yeah, which is why it was uncomfortable. I quite like my air conditioned cocoon that early in the morning. On the way home after a long day it’s fine, roof down tunes up 8)
 
Did you get to the bottom of this yet Paul?
(I’m after reassurance it ain’t the fan so I don’t have to deal with the guilt of stealing your fan of you the other month :oops: ).

It’s on mine now by the way. Despite the matching part number it wasn’t quite the same as the original one, but the guy that fitted it for me just took it apart and swapped all the gubbins into the old shroud/bracket and it’s all good.

Thanks mate. Hope you solve this (and hoping the outcome means you are not ruing the day you sold me your spare fan!).

Rich.
 
Rich8 said:
Did you get to the bottom of this yet Paul?
(I’m after reassurance it ain’t the fan so I don’t have to deal with the guilt of stealing your fan of you the other month :oops: ).

It’s on mine now by the way. Despite the matching part number it wasn’t quite the same as the original one, but the guy that fitted it for me just took it apart and swapped all the gubbins into the old shroud/bracket and it’s all good.

Thanks mate. Hope you solve this (and hoping the outcome means you are not ruing the day you sold me your spare fan!).

Rich.
Click to expand...

Hi Rich,

Glad you got it sorted but apologies for the part number confusion! That fan has been test fitted to two Z4s successfully - a 2.5si and 3.0si. I cannot remember what model you have but it might be worth posting, because a lot of people (myself included) will be under the impression that they are all the same.

Got my issue sorted in the end, thanks - must have been a slow leak because it came good with another re-oil and re-gas. :)
 
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