e34 heater

[dave525]

hi,i have an e34 525 24v non vanos and the heater is playing up.it is fine whilst driving but at idle it goes cold.ive fitted a new thermostat and checked the valve unit in the engine bay.the temp gauge shows half way and the hoses feel warm.i know about the dodgy water pumps on these but would this cause my fault.any one have any ideas on this.cheers

[DanThe]

Probably a partially blocked matrix if its only at idle speed, the dodgy water pumps have plastic impellers that come free from the drive spindle, if that was the case it would be cold all the time and your gauge would be in the red. Best thing to do is get it in the sink, give it a good washing out and then fill it with boiling water and kettle de-scaler

[dave525]

flushed through matrix,nice and clear.no blockages

[Yaninnya]

The additional electric water pump gone. It is mounted under heater valves just near fuse box.
Jan

[dave525]

my car hasnt got the additional water pump.i thought it would be this too.i had the valve unit off and split it,its just two solenoid operated valves that block off the output pipes when activated.

[Yaninnya]

Are you sure? What is the year of it?
Jan

[dave525]

year is 1991.definately no extra pump.going to check water pump next.wonder if vanes damaged somehow causing poor circulation at idle.coincidently head cracked recently.wonder if faults are linked.just feels like no water flow through heater at idle