Welcome to Bimmerfest -- The #1 Online Community for BMW related information! Please enjoy the discussion forums below and share your experiences with the 200,000 current, new and past BMW owners. The forums are broken out by car model and into other special interest sections such as BMW European Delivery and a special forum to voice your questions to the many BMW dealers on the site to assist our members!

Please follow the links below to help get you started!

Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > Classic Bimmers

Classic Bimmers
Discussions pertaining to vintage and classic BMW models here...

Thread Tools Display Modes
Old 10-13-2013, 08:41 AM
JustKeepsOnGoin JustKeepsOnGoin is offline
Registered User
Location: Montclair, VA
Join Date: Oct 2013
Posts: 3
Mein Auto: 1984 733i
How can I get my heat back on 733i?


New to this forum. I have a 1984 733i that probably has 450K on it....The only thing that has been replaced is the water pump. I had the transmission rebuilt in 1995 because I by the time I changed the fluid, I had waited waaay too long.

Anyway, I have kept the car on full heat setting for years because the last time I had turned the temp setting to cool, it almost didn't make it back to providing heat....and that time it made a clanking sound when the heat was coming back on.

Now, it just blows room temperature, no matter what setting it is on (up/down, auto, etc).

Heater control valve?

Heater diverter valve?

Not sure, but for one of them which is located in the engine compartment, top passenger side on the firewall, I took the hose off and found nothing blocking or closed in there. I flushed that system out with a hose (some darker gunk came out too) and refilled with proper coolant after it was flowing clear water. No luck.

I don't have the bucks right now to fix, the rest of the car runs great. Operating temp is normal, drives fine. No coolant leaks inside the car foot wells or on the ground.

I'm hoping for an easy fix suggestion that will let me keep the heat flowing on the floor at all times. I don't need to adjust anything for cabin temp. Something I can do myself that won't cost me anything. I don't mind bypassing valves if need be.

Reply With Quote
Old 12-04-2013, 07:57 PM
mach8 mach8 is offline
Old School Luxury
Location: California
Join Date: Dec 2013
Posts: 20
Mein Auto: 735i
not sure about your car, I have a '88 735i and the heater control valve in the engine compartment has two solenoid operated vales. When the rubber in the valves goes the heat stays on all the time, if there is no power to the valves they stay open so again you have heat all the time.

If the switch controlling the valves is faulty and they have 12 volts all the time they will stay closed - no heat.

there is an auxiliary water pump attached to the heater control vale on the intake side.
If you aren't getting any heat your aux water pump may not be working, if you have one, or something may be plugging up the valve I'd guess.

I'd check the Shogun's BMW site as well as Timm's BMW site on meeknet.co.uk
Reply With Quote
Old 12-05-2013, 06:45 PM
John in VA John in VA is offline
Officially Welcomed to the 'Fest
Location: Leesburg, VA
Join Date: Feb 2006
Posts: 321
Mein Auto: '74 tii / E28s / '03 530i
One of the best E23 forums - http://www.bimmerboard.com/forums/e23/
Another great resource - http://e38.org/e23/
Reply With Quote
Old 12-05-2013, 08:11 PM
JustKeepsOnGoin JustKeepsOnGoin is offline
Registered User
Location: Montclair, VA
Join Date: Oct 2013
Posts: 3
Mein Auto: 1984 733i
Thanks much to both of you....ironically, it "fixed itself" a couple of days ago....hadn't run the car for a while and the battery barely started it after three tries....I revved it a bit when it did turn over and the heat has been on since....who knew?!
Reply With Quote

See More Related BMW Stories

Forum Navigation
Go Back   Bimmerfest - BMW Forums > BMW Model Discussions > Classic Bimmers
Today's Posts Search
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -7. The time now is 01:43 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
© 2001-2015 performanceIX, Inc. All Rights Reserved .: guidelines .:. privacy .:. terms