M60 engine coolant flow direction diagram ?

[84318i]

Hi,

Does anyone have a diagram showing the orientation of the coolant flow in the m60b40 engine? I need this to ensure the coolant hoses at the back of the water accumulator pipe
are connected correctly to a heater core on my car.

Looking at the picture below, with the water accumulator pipe that only has 2 outlets which one is OUT vs IN ? I am going to be using a 740i water pump with the expansion tank nozzle on it.



Thanks in advance!

[Layne]

Can't remember off the top of my head, and can't find my book. But I'll say this, a heater core has no concern for which direction the water flows through.

If you have an M60 car to look at or can find a pic, I do know that the hose going from the water manifold to the little AUX water pump under the heater valves is the hot water supply, and the hose coming direct from the firewall back to the water manifold is the return. The return hose is slightly bigger than the others, but I don't know if the nipples on the water manifold are different sizes.

[Mykk]

Front to rear, hot coolant leaves out back of head through crossover and through the pipe in the valley to the water pump and then to top of radiator. The only reason it joins the water pump is for the bypass while thermostat is closed.

The big pipe is main flow, little pipe is heater core

[84318i]

Thank you Layne and Mykk!

The rear water accumulator pipe outlets are exactly the same size for the heater core pipes, and I've looked inside the rear water accumulator metal pipe and looks like the two sides have a divider in between.

[Mykk]

VP_Intke_VC_SP_FF_Oil50.jpg

In this pic, the left outlet is heater core send. The right one is heater core return going to water pump. It's true a heater core doesn't care about flow direction

I've looked inside the rear water accumulator metal pipe and looks like the two sides have a divider in between.

That split divider is in the bigger pipe (on the right in the picture above), that's the water flow leaving the cylinder heads. The heater core return is isolated from the cylinder head flow.

[84318i]

Mykk - thank you, this helps!

[Irwie'C]

Here's an M60 cooling circuit pulled off a bmwtechinfo page. Should help you out with further questions that might arise.
It's an e32 version, but I guess there shouldn't be any difference, since the e34 shares the same system.

[84318i]

Irwie'C - nice ! Do you have a similar diagram for M62 with only 2 rear water accumulator pipe outputs vs 4 ?

[shogun]

M60 coolant circuit diagram https://i.imgur.com/MV1c0xr.jpg
MV1c0xr.jpg

[84318i]

So, guys to bump this up. I have an issue where heat only blows hot after sitting at red light, as soon as I am moving hot turns into warm and not longer hot.

I've used infrared thermometer and measured various points (water pump, thermostat housing, upper and lower radiator hoses, and more importantly rear crossover pipe and the aluminum heater core pipes going through the firewall have a 10degree delta.

If the heater core really doesn't care about which way the flow is going through it, is it possible that the Heater Core Valve itself does care about the flow? I've confirmed that the heater core valve is OPEN, and I've confirmed that my HVAC controls work and send the voltage to the valve as designed (checked this by looking through ETM and used my DMM at the heater core valve 2pin connector).

So, valve IS open, heat is only working when car is at idle...once moving I don't have heat.

1. Does the heater core valve care about the direction of the flow?
2. Do you think main water pump alone is not enough to push the coolant through the back of the water accumulator pipe and into/through the heater core?

ALL coolant components are brand new and gem, so it's not a bad water pump/t-stat/clogged radiator/heater core or anything like that. Radiator being used is new S54 rad, rest is m60 specific stuff with the exception of the expansion tank (e30 tank).

[eddycooper]

Just to clarify - are you using the aux water pump or did you leave that out?

[84318i]

Just to clarify - are you using the aux water pump or did you leave that out?

No aux fan , someone stated it’s 100% unnecessary, which I am now doubting .

[eddycooper]

Not the aux fan, the auxiliary water pump. The one that helps push water through the heater valve to the heater core.

This guy: https://www.ecstuning.com/b-genuine-...p/64118390063/

[shogun]

see workshop manual pic on page 64-11/2
closest to center of car engine bay = return from heater core
middle heater core feed right side
outside heater core feed left side

[84318i]

Not the aux fan, the auxiliary water pump. The one that helps push water through the heater valve to the heater core.

This guy: https://www.ecstuning.com/b-genuine-...p/64118390063/

Yes, not using or running aux water pump . The back of the rear water accumulator pipe two outlets are directly connected to the heater core, one line has a valve and valve is open. Both pipes are hot, but there is no heat when moving.

So I am wondering if the design of the m60 cooling system requires the aux water pump to keep the coolant moving through the heater core or should it still move enough even without it ?

What happens with 540/740 cars when the aux water pump dies or is disconnected ? Does the heater core still get enough hot coolant for the heat to work or does not stop working ?

This would be helpful to know if someone with 530i 540i or 740i can easily test

Thanks

- - - Updated - - -

Thank you Shogun for the 64/11-2 diagram.

[eddycooper]

My understanding of the aux water pump is that it helps keep water going to the heater core when the car is at lower RPMs. I've never been without mine so I can't say from personal experience. It doesn't quite fit with what you're seeing but I'm thinking it would help in your situation. Honestly your symptom of no heat while driving sounds more like a bad thermostat but I'm sure you've ruled that out with the temperature gauge.

[shogun]

I have a German language training manual on the IHKA. Main purpose of the aux water pump is to pump hot coolant from a certain min degree C of the coolant thru the heater core at 950 l/h, no matter what the engine RPM is, so it is just for more comfort for heating. If no aux water pump is installed or the aux water pump is not working, heating inside the cabin changes slightly depending on engine RPM. But there is enough heat, many cars are running w/o aux water pump.

Then it is also needed if the car is equipped with parked heating system.