Just replaced heater valve and now no heat!

[RenaissanceMan]

I just replaced the heater valve in my '95 525it to try and cure a problem in which the heat was stuck 'on' in the floor vents, but after replacing now I can't get any warm air out of the vents, period. Anyone have any ideas what could have happened? It's a brand new heater valve... not used... Auxiliary pump sounds like it's running normally when I turn the key on...

Not sure if this is a clue, but I'm only getting 12 volts from pin 1 of the 3 pinned plug that plugs into the heater valve on top. I'm not getting any voltage, whatsoever from the other 2 pins... Is this normal operation?

Thanks in advance-

[bad_manners_god]

Maybe the system has to be bleed, was any coolant lost changing the heater valve?

[632 Regal]

exactly what I was thinking... cant find my Bently to look at the schematic.

Maybe the system has to be bleed, was any coolant lost changing the heater valve?

[RenaissanceMan]

Maybe you guys are onto something. I just took the car for another test drive and the heat is working again. I will bleed the system again but I'm also wondering if I need to change the thermostat...

[632 Regal]

Only need to change the thermostat when it's broken or for regular maintenance

[RenaissanceMan]

Yes but won't a stuck open thermostat also cause symptoms of no or limited heat?

[Kibokojoe]

Bleed then bleed then bleed again. Front end slightly angled up.

[shogun]

I would change the thermostat in regular intervals of 2-3 years as preventive maintenance, they WILL break anyway, and before you have a overheated cylinder head which costs a lot of money, do yourselves a favour and change the t-stat in certain intervals.They break all after a certain time of thousands of hours bending! I have seen too many broken t-stats.