heating air question

[deQuincey]

hi

I have a terrible question, and here is the place to ask it, because I think that this e9 car is different than the new ones

following picture is the schematic drawing of the heating system of the e9, basically there is a air fan blower, a radiator (water-air heat exchanger) and some plastic chambers and plates that can be operated to change from warm to cold air in the car

so the function is more or less like this: hot water from the engine comes through tube Nº15 and enters the radiator, warms the pipelines of the radiator and comes out through tube Nº14, as a result the radiator is hot

then the fan will make air pass through and across the radiator and that air will be warmed up

this is simple and I assume true, but, here are some doubts:

when you want hot air, you pull the lever to the red area in the dash, and then a plate is moved onto an adequate position that allows the air from the fan pass through the radiator and into the car, so HOT air, OK

when you want cold air, you pull the lever onto the Blue area, the plate is moved to a different position, and the air surpasses the radiator through other path and enters the car without been heated

big question comes now: is there in this system any valve or tap that interrupts the flow of hot water from the engine to the heater radiator ??

I CAN NOT FIND ANY !! not in the engine compartment, not below the dash or heat exchanger

in modern bmw´s there is such a valve, some of them mechanicals (older cars as e12,...) and other electricals

but our e9 has NOT a valve, right ??

if this is not true, please tell me where it is and how to fix it !!

I will appreciate your ideas and help VERY much

regards

 

[HB Chris]

Sorry, hot coolant is always in the heater core and the flaps operate as you describe. In the 2002 they also had the valve you were hoping for but won't find..

 

[deQuincey]

thank you for confirming it

does anyone tried to install an external valve to avoid hot inside the car in summer time ?

regards

 

[x_atlas0]

I suppose you could use one from a later car, like the E34. The part in question, the heater control valve, is simply a pair of solenoids blocking or allowing coolant to flow.

http://www.realoem.com/bmw/showparts.do?model=HE63&mospid=47410&btnr=64_0114&hg=64&fg=18
(part #15)

It is about the size of a grapefruit. It would be pretty easy to connect some 2-position toggle switches to the solenoids to stop the flow. The important thing is that you still allow for a complete fluid circuit.

 

[deQuincey]

I suppose you could use one from a later car, like the E34. The part in question, the heater control valve, is simply a pair of solenoids blocking or allowing coolant to flow.

http://www.realoem.com/bmw/showparts.do?model=HE63&mospid=47410&btnr=64_0114&hg=64&fg=18
(part #15)

It is about the size of a grapefruit. It would be pretty easy to connect some 2-position toggle switches to the solenoids to stop the flow. The important thing is that you still allow for a complete fluid circuit.

ok, I see, this can be the choice

thank you

regards

 

[HB Chris]

Given that our coupes don't have the best ventilation I don't feel any residual heat from my heater box. Nothing beats both windows down and your hands on the wheel.

 

[deQuincey]

Given that our coupes don't have the best ventilation I don't feel any residual heat from my heater box. Nothing beats both windows down and your hands on the wheel.

I am afraid that I have to tell you that in my case I feel hot air in the vincinity of my knees,

So my choice is to buy a valve and define two periods in the year: the cold season (november-april), and the hot one (may-october) :-D:-D

and subsequently open in the cold season, and close in the hot one !!!!

thanks

 

[Bwana]

Be careful when by-passing the heater core. There are some cars (not necessarily BMW's) out there that will overheat instantly if the water is not circulating completely (Datsun 2000 comes to mind). I've not studied the system closely but I'd recommend a bypass that still allows full flow without going thru the heater core. Being in Houston I might pursue this myself

Just my $.02

 

[x_atlas0]

Be careful when by-passing the heater core. There are some cars (not necessarily BMW's) out there that will overheat instantly if the water is not circulating completely (Datsun 2000 comes to mind). I've not studied the system closely but I'd recommend a bypass that still allows full flow without going thru the heater core. Being in Houston I might pursue this myself

Just my $.02

That's why I suggested the BMW unit, as it allows coolant to circulate when the heater core is bypassed.

 

[deQuincey]

hi

thanks for your answers

I am worried about that possibility you tell me, It will be terrible if that overheating occurs due to the interruption of the circuit when closing the valve to avioid the core

but I can not understand why, considering that if you take the E21 as an example, you can find two different constructions of that system:

whith electric valve: I can assume that in this case a by-pass can be made (i assume because I don´t know the function of this valve number 7)

with manual valve number 3, I see a simple valve that will close the water flux and no by-pass will occur

so do you think there will be a problem ?

regards