Heater Probs...New owner....

[cope]

Thanks for the info. I have a new Bowden Cable on order. This forum saved me a bundle.
Best,
John Paul

[vjmvjmvjm]

Thanks everyone for the write-up. Some observations follow:

1. The end of the cable is attached via a screw to the adjacent dash / HVAC assembly. Through fatigue or through turning the HVAC control to hot beyond the stop (or both), the plastic connection on the end of the cable breaks off.

2. After I discovered this to be the case, I wondered how I would reattach the cable sheathing to the dash / HVAC assembly. Note that the sheathing on the end of the cable (bright yellow) has two diameters. It is necessary to restrain the sheathing from moving toward the front of the car when the knob is turned toward hot.

3. A P-Clamp works fine as a solution. See the attached graphic. These plastic clamps are used to attach coax and electrical cables. Find a P-Clamp that fits the smaller diameter end of the sheathing, but is smaller than the larger diameter portion. Place the P-Clamp over the small end of the sheathing, and reuse the screw from the original attachment.

YMMV. OAC.

Vic

[jmoti]

Thanks to everyone who's posted on this thread, but I have a particularly elusive heater problem that I'd love some input on. My heater generally blows cold, though occasionally (generally when parked) it will blow lukewarm. I checked the Bowden cable, and it seems fine - it moves the flap and doesn't appear broken. I checked the heater valve by feeling both input and output hoses, and that seems fine (both are hot). I think the thermostat's ok, as my water temp is rock solid at the middle. I'm stumped - any other ideas? Thank you!

[trickiekid]

Wow, the first post was 7 years ago. How is your coolant level? If its low it won't blow hot. Also, Make sure that you bled the system properly

[jmoti]

Thanks for the suggestion - I forgot to mention that my coolent level's fine, and I also tried burping the system as described in this thread. And yeah, it seems that this problem keeps cropping up over the years, in some form or the next... :-)

[vjmvjmvjm]

Originally Posted by jmoti

I checked the Bowden cable, and it seems fine - it moves the flap and doesn't appear broken.

How far does the cable move the flap? When you turn the dial toward hot, the cable should completely close the opening toward the front of the car. If it doesn't close completely, then fresh (cold) air gets mixed in. When you're not moving, less cold air comes in so the mixture gets warmer.

Is the end of the cable sheathing still attached to the panel behind it, or is the end loose? The end of the sheathing closest to the flap should be solidly attached to the panel behind it.

Vic

[jmoti]

Hi Vic,
Thanks for your reply. To be honest, when I had it apart I couldn't actually see a flap (maybe I didn't take it far enough apart?) I took off the glovebox, knee brace, and plastic duct, and I could see the cable mounted to the side of what I assumed was the heater box. It moved fore and aft continuously when I twisted the knob, so I assumed it was ok. I'll take it apart again and take a closer look - maybe that's the problem after all. Thanks again!
justin

[jmoti]

UPDATE: Vic, you are absolutely right! Turns out the little yellow plastic cable guide had separated from the heater box, and I just hadn't noticed it before. That was wedging against the yellow lever and stopping the flap from opening the whole way. Thank you!!

[redhottaudrey]

And another one... My heat is blowing luke warm too. The coolant level is full. The guy at AutoZone said it may be the thermostat but my engine temp goes to the middle when hot... so can it still be the thermostat that's causing the problem? I'm really hoping I don't have to go through all these other steps but thanks for all the info guys!

I checked some things and both hoses going into the firewall are hot. And I can here the click when switching the lever to hot/cold.

[b.u.ti-ful]

How much air can you feel blowing?

Have you tried it on recirculate?

I just changed my cabin air filters and they were so clogged up that no fresh air could flow into the car.

[redhottaudrey]

Plenty of air is coming through.

It does seem to be warmer when it's on recirculate.

Probably a good idea to change the filters regardless.. But I'm an idiot when it comes to car stuff so is there a forum on how to do this?

[b.u.ti-ful]

It is unbelievably difficult on our cars.

http://www.318ti.org/forum/showthrea...t=micro+filter

[jmoti]

Ok, having just received sage advice here, let me try to distribute some of my own. First, if your temp gauge is solidly in the center, it's *probably* not your thermostat. Bentley manual suggests that you can test this by feeling if the top hose of your radiator is hot - if so, the thermostat is working, allowing water to flow through the radiator. Not the best test, but it is one indicator.

Secondly, I'd check your heater bypass valve. It's tough to see - you can see pictures of what it looks like at http://www.pelicanparts.com/bmw/tech...e-Cleaning.htm . When the engine is warm and the heater going, both input and output hoses should be hot. If that's the case (as it was in my car), you know the problem is further downstream - most likely the cable that goes from your rotary heat control to the flap on the heater box. Some kind folks have provided step-by-step directions to get to this earlier in the thread, so I'd print them out and start pulling apart your dash. If you dont' feel comfortable, maybe point your mechanic in this direction - it's not the first place they would look (as Autozone showed), but it is the most likely in our cars. Good luck!

[redhottaudrey]

Thanks Guys! I'm heading to the mechanic in a bit & I'll be making sure he does it right. Both hoses are hot so it must be the Bowdon cable & the flap. I wanted to start taking it apart myself but maybe next time.

[znine]

Thanks guys! I've been freezing my ass off all winter thanks to this cable.

Someone had already drilled and screwed my yellow clip but it snapped off. I reattached it with a homemade P Clip but it's not perfect. Does anyone know the part number for the cable? My lever moves through it's full range of motion but the knob for some reason does not.