Temperature Problems

[Saint7376]

I'm in the middle of retro fitting airconditioning to my 1995 320i. I've have recently changed the old HR heater box to the IKHR version out of a 1993 M3 and fitted the new double water valves and wired them in, having bled the system 3 times the temp gauge slowly climbs from normal to just above the 3/4 mark before falling back down to the normal position suddenly where it will stay for a few mins then climb again, this only happens when the engine is under load and never when it is idling.

Also the Bently manual refers to a mixing actuator on the wiring diagram I have found the plug but I'm unable to find it on the actual heaterbox.

Any idea's would be very welcome

[Jared at Pelican Parts]

hmmm, does it get hot only with the A/C activated?

[Saint7376]

I went back over the system today and ran the car for a short time, the coolant seems to heat up quite quickly but the oil temperature rises normally and doesn't go above 95 degrees C.
the coolant seems to overheat when the heater valves are closed or the blower fan is not drawing air over the heater matrix. the a/c pump is not connected at the moment.

[Jared at Pelican Parts]

Are you sure all the air has been bled from the system?

[Saint7376]

I've bled the system several times and there are no bubbles coming out of the bleed hole on the radiator and it did take around 10.5 litres of coolant to fill it up, could it be the themostat sitting permenantly partially open?

[Jared at Pelican Parts]

I cant think of anything else realy, without knowing

1. What the old system was.

2. What the new system is

3. Where you are, US never got the E36 320i models.

[Saint7376]

I'm in the United Kingdom

The origional system was the simple three knobs for controlling the heater (fan speed, temperature, vent position) and one button for rear demist. A single matrix and valve, the ETM calls it HR

The new system is a split ventillation airconditioning unit with separate zones left and right and four control knobs (fan speed temperature left, temperature right, and vent position)and three buttons airconditioning, recirculation, rear demist. Two matrix's and two heater valves. it has a label on it marked IKHR.

[Jared at Pelican Parts]

Is this a common swap for UK cars? I've never heard of it. Did someone suggest it for you? Do you have any material that goes over how it works? I might be able to figure something out....

[Saint7376]

I've not heard of anyone trying, normally the airconditioning equipment is expensive enough that people tend not to bother.

As far as I can tell the heater boxes themselves are identical between the us and uk spec cars

[kocio67]

If you are going with dual zone climate control you need heater box with dual heater radiator (3 hoses going from valve to the heater) and two temperature sensors (driver, passenger). I am not sure if your heater box is ready for dual zone. Maybe you should buy US heater box on EBAY. What about HVAC computer? Is US (dual) and UK (single) the same?

[Saint7376]

I found out the problem was the water pump, it's now been changed along with the thermostat and everything is back to normal.
I have already fitted the dual zone manual HVAC heaterbox to the car (exactly the same US to UK even the same part no.) all I need to do now is fit the pipework for the a/c to the compressor and I'll have full aircon on a car.

Thanks all