Heater not blowing hot.

[Pete]

My car's heater seemed to work intermittently, now I am not getting heat.

It isn't a case of me not turning the dial in the middle of the vents as I have checked that.

What can it be and how can I diagnose please?

I have a 54 4.8is

[graemeX5]

Hi

If all the heater controls are set to warm and the car has been running for at least 10 mins and the car is warmed up then the heater should warm up.

I would check if the iengine getting warm or if below half way point on the temperature gauge when its running it could indicate the thermostat is faulty which is a cheaper fix to try, and I believe is a diy job as some have done on here.

If it's not that then I'm not not sure if the engine is running at the correct temperature it could be several things.

Graeme

[Horizon]

[quote="Pete"]
My car's heater seemed to work intermittently, now I am not getting heat.

It isn't a case of me not turning the dial in the middle of the vents as I have checked that.

What can it be and how can I diagnose please?

I have a 54 4.8is
[/quote]

As Graeme has said, first port of call is checking that the car is at the correct running temperature with the temp gauge at the halfway mark 95-110degrees C. Checkable via the hidden menu.
The climate control unit should open and close a selenoid valve in the hoses that go from the engine to the heater matrix ( heat exchanger behind the dash board. The fan then blows air through the heater matrix ( internal radiator / heat exchanger into the cars interior.
If the engine coolant is at the correct temperature and you can feel cold air blowing out of the vents it sounds like it could be the water control valve is not opening, so not allowing hot water into the matrix.
So maybe a faulty selenoid valve, or it's not receiving power / signal from the climate control unit in your dashboard, havnt got the X5 anymore, so can't tell you where the valve block is located, usually on the bulkhead under the bonnet. If accessible feel the pipes going in and out to see if they are getting hot when the car is up to temperature.

[Pete]

Thanks, just the kind of feedback I wanted. I drove to Manchester and back today (25 mins each way) outside temp was 1.5degrees c and the heater was set at 32 degrees and warm (not hot). Temp gauge was in the middle but I'll check what the computer says.

I'll keep you posted. Lots of similar issues on the Internet but not many stating how they solved it.

[Horizon]

This is what the heater valve looks like, probably need a multimeter to check to see if there is a signal/  oltage to the selenoid valve. Looks to be 3 inlet / outlets.
Possibly return and feed or 2 zone / 2 matrixes.
But all pipes should be hot.
If you havnt got a voltage to the selenoid from the climate control, no worky
also check the water level in the expansion tank, or if you've recently changed the coolant, it could be airlocked and need " Burping "

[henrym3]

Had a very similar problem where I had heat up top and cold feet, one of those solenoids had failed, replaced from a breaker for £18 and everything is heat, heat heat.

[Pete]

Thanks again for the feedback.

I've checked the coolant and it was low so I've topped it up with about 400ml so that the marker is in the correct position. Hopefully that will sort it. If not, I'll get the valve checked and changed if necessary.

[Pete]

Topping up didn't solve it. Next step, water control valve from a salvage.

[henrym3]

Should mention, make sure you have checked for voltage at electrical connection at water valve as Horizon suggested and if there isn't any check fuses.

[Horizon]

[quote="henrym3"]
Should mention, make sure you have checked for voltage at electrical connection at water valve as Horizon suggested and if there isn't any check fuses.
[/quote]

Selenoid could be OK, but not getting voltage to operate. I.e. Bad connection, fuse or faulty climate control unit, as Henry suggests check for voltage at the plug going to the selenoid, ( usually located next to selenoid.)
Get someone to turn the climate control ON whilst you have hold of the selenoid she, you may feel them clunk as it's activated.

[X5-D-Sport]

Re these solenoid valves.... with the AC switched off... center vent set to Center...

My interior heaters are either full hot or full cold.... there is no in between...

If I say... dial up 20'C, it will get hot..... very hot.
I adjust down a degree at a time over about 15 minutes.... stays bloody hot...

When adjusted down to 16.5 degrees, it suddenly get TOTALLY cold.... no in between.

Is this a symptom of this solenoid valve failing  ???

regards
Grant B

[Horizon]

Could be selenoids or the signal/  voltage it receives from the climate control unit. Remember the old BL cars, you had a sliding temperature bar/knob that had a cable that went to a ball valve on the engine / heater feed. The selenoids just replicate this function,  in an automatic fashion. Yours maybe being told to be open or closed at the incorrect temperatures. A selenoid is fully open or closed, so sounds like the climate control unit or its temperature reading abilities are playing up.
The temp reading probe has a fan that blows cabin ambient air over it . Is the fan working ? Is it reading correctly ?
Don't know if this will work,  get someone to alter the required temperature and see if you can hold the selenoid to feel if its operating

[X5-D-Sport]

Horizon... good information...
Where is the cabin probe & its little fan plz ?

[henrym3]

I think but not 100% that these are the probes that horizon is on about
4 is the evaporator temp sensor
5 is the heater temp sensor
3 is the final stage resistor

[Horizon]

[quote="X5-D-Sport Salisbury"]
Horizon... good information...
Where is the cabin probe & its little fan plz ?
[/quote] the little fan and probe live behind the facia of the climate control unit, you will see a stamp size grille

http://www.import-car.com/bmw-climate-c ... s-repairs/