e63 645ci driving me nuts heater problem

[Drifter17a]

All,

I have flushed the coolant, bleed the system by opening the reservoir cap, start engine and then after 2-3 minutes close the cap and drive the car.
after it cooled, did top it up.

heater valve on passenger side( RHD) seems to operate and both inlet and outlet is hot hot. Heater valve is item number 12 on the link below.
https://www.realoem.com/bmw/enUS/sho...diagId=64_1363

Car is still blowing cold air unless I rev it to 3000 and above whilst driving and it blows a very mild warm air.

When I opened the heater valve pipe, I had a hose pipe inside of the reservoir and saw water coming out of the heater valve when pipe number 4 from the pic above was plugged in and water was coming out of the heater valve on where pipe number 5 would have connected it .

However when I blowed inside pipe number 5, it was almost blocked. nothing was going through so not sure why and whether this is by design .
First test suggests water is going through the heater core and second test suggests it is blocked ?

why heater core has three in/out connections? which one is in or out on the link below?
https://www.realoem.com/bmw/enUS/sho...diagId=64_1350
what is your thought or suggestion?

Does anyone know why BMW has three input/output on heater core? It is normally 2 only . see below

https://www.realoem.com/bmw/enUS/sho...diagId=64_1350

[Timm]

The heater core is the same type as in every other big BMW with dual climate control - here's the circuit:



Try bleeding again - if it only works at high revs that indicates that you are short of coolant - as the heater system is at the highest point it is always that that fails first. More info on bleeding here (for E31 but the plan is the same on all the V8's:

[Drifter17a]

you are a superstar thanks

coolant level on expansion tank is on max so it could be radiator is not getting bleed and I do need to follow the video and bleed it on hill

as far as I understand the aux pump is just for the rest heating when car is off so if it fails, coolant should still flow when car is on right ?

Untitled.png

can you please check my drawing above, is it right to assume the red ones circled and pointed to are inlet and blue one is outlet ?

does the radiator or core heater has a thermostat so if I tried to put a water hose in it , it won't flow until thermostat is open ?

- - - Updated - - -

I also have read the codes and see this

Ihka: Auc sensor which is a fault that I can't delete


finally i should say both sides of the heater valve was very hot, what is purpose of the heater valve if it is used to send input into the radiator on both sides?

[Drifter17a]

Ok i figured it out using various forums.

the two pipes connected to the heater valve are both inlet i think which I don't understand why you have two inlets into a heater valve .

then outlet goes to back of thermostat.

now when I blow through the pipe or put hose pipe on inlet, no water comes out of it the outlet even if I open the pipe connected to the water pump which will bypass the thermostat .

could it be some knob head before me has used different anti freeze colour and has blocked the heater core outlet ?
when I put a pipe on inlet, it just doesn't flow into it

see attached pic

blue one is also the high point out of the three inlet/outlets so it makes sense as hot water flows from the highest point back into engine

how can you bleed e63 645 ci apart from top up coolant, and leave cap open for few mins before it boils then close and drive off .
few hours later check level. I have done it 10 time

[Timm]

Nah, the heater valves have one hot inlet from the auxiliary pump - and then two hot outputs that are connected to the heater matrix - one valve serves the passenger, the other valve serves the driver - there is a single outlet from the heater matrix that then returns to the water pump (not the thermostat). The valves work in reverse in respect to the E31 type, the E63 needs power to OPEN the valves whereas the E31 type needs power to CLOSE the valves. In all other respects the operation is as described below:

[Winkie]

I just got a 645 lately and the heater in it stopped working I got new heater valve on ebay and everything works great now the old valves the rubber failed and I found pieces in the water pipes so you met have a blockage as well

[Drifter17a]

ok, I changed the heater control valve and that wasn't the cause. It helped and improved heating as upon checking I realised previous one had a stuck valve.

Now car is warm as long as it is revved so that leads me to belive it is due to the heater valve which is connected to the radiator pipe.

My theory behind it is, when reved the water pump is working harder so water pushes its way through the valve however when idle, the pump or heater valve has no power to push any water through.

bought a second hand one and awaiting arrival

[Timm]

If you have a full cooling system (the usual cause of 'only gets hot when revved' is lack of coolant) then next is the auxiliary water pump:

https://www.meeknet.co.uk/E64/BMW_E6...eplacement.htm