Heater issue (Solved)

[BMWX5CHI]

So I recently replaced my expansion tank, along with various hoses. Now, I seem to have an issue with the heater. No hot air seems to come out of the vents. It blows semi warm air from drivers vent, and that's only for a few minutes. Won't blow warm through passenger vents at all. After a few minutes, it stops blowing warm air through drivers vent. What the hell is going on? It was working fine before my expansion tank started leaking. I bleed the system properly before anything. I don't see what else could be causing this. Does anybody got any ideas to what could be causing the problem ? Used to blow hot air just fine.

Update Solution: Heater Valve Failed. Rubber gasket seals inside heater valve started to deteriorate. Replaced heater valve and problem solved. Continue reading for more important info.

[Thecastle]

Originally Posted by BMWX5CHI

So I recently replaced my expansion tank, along with various hoses. Now, I seem to have an issue with the heater. No hot air seems to come out of the vents. It blows semi warm air from drivers vent, and that's only for a few minutes. Won't blow warm through passenger vents at all. After a few minutes, it stops blowing warm air through drivers vent. What the hell is going on? It was working fine before my expansion tank started leaking. I bleed the system properly before anything. I don't see what else could be causing this. Does anybody got any ideas to what could be causing the problem ? Used to blow hot air just fine.

Well it's possible there is still an air pocket in the heater core, since this was the last thing that was done it's the most likely culprit.

However, I had a similar thing happen after changing my coolant and it was the heater control vavle died. Apparently this fail with regularity on bmws just do a search and you'll find a ton of diy guides.

So assuming your system is fully bleed, Hester valve is okay, wiring is okay to the valve, then it could be a clogged hester core or failed controller for heating.

Btw, I replaced my heater valve with an eBay part and now the heat runs constantly. The part was labeled as compatible with an e70 but was the e60 heater controller and they are similar but not compatible replacements

[BMWX5CHI]

So today I went out and all was working great, both sides were blowing hot air as before. but 10 minutes later when I restarted the X, she started blowing lukewarm air again. I touched all hoses and they feel hot. Located what seems to be heater control valve and all of the hoses are hot. What can be the problem ?

[Thecastle]

The heater control valve is located on the driver side of the engine bay. It sounds to be similar symptoms to my issue. Probably a bad heater control valve. The hoses going to the passenger compartment from the heater valve will en be hot due to proximity of the engine. If the engine is at full temp then the hoses will be about 100c so hot you won't be able,to,touch them for more than an instant. I'd bypass the valve with a stint to see if your heat problem goes away.

Here is a troubleshooting guide. BMW and MINI DIY – No Heat – Diagnosing Heater Problems How To Diagnose | Bavarian Autosport Blog

[BMWX5CHI]

I'm going to bypass the valve and see what happens. In case that doesn't work, (praying it does) i'm thinking it's a clogged heater core. I'm trying to figure out where the inlet and outlet hoses are to attempt to flush it out.

[BMWX5CHI]

Took off the heater valve and it's toast! Looks like internal the rubber portion of that stops flow has fallen apart and has clogged up preventing flow of coolant. It's in pieces. Now i'm scared that some of that has gone into the heater core. Trying to figure out which of the hoses is the inlet and outlet. By the looks of it, i'm going with common sense and following the hoses as pictured. Going to try to siphon the inlet hoses to pull out any junk that might have gotten through.

[BMWX5CHI]

As you can see the heater valve is toast. I was able to blow out some chunks of rubber from the heater core using distilled water and a little bit of pressure. Blew in from the outlet side so that it would come out the inlet side. I'm hoping I got the outlet inlet sides correct. Just ordered replacement heater valve $214 shipped. Hopefully this fixes the problem. Wifey isn't happy at all.

[pshovest]

Remind Wifey, your DIY skills saved her $450 labor. I doubt the rubber bellows pieces will plug the heater core, but flushing can't hurt.
I think hoses 5 & 6 are inlets to drivers and passenger side heater cores and hose 7 is the common outlet. Thanks for the followup and pics of the failed valve.

[Thecastle]

Glad the replacement worked for you! I had the same problem, where after a coolant flush, I only got heat on the passenger side. I ended up purchasing a new heater valve on fleabay and it completely solved my problem. These valves commonly fail on BMWs.

Nothing wrong with oem parts, however if you shop you can find the vavles for $85.

[BMWX5CHI]

Everything seems to be working great. Had to bleed the system out again and add more coolant, but problem is solved. Both driver and passenger blow hot air. The temperature in Chicago dropped to single digits and with the wind chill, it feels like it's in the negative numbers. With the heater working, wifey is now a happy camper. Thanks to all who helped out.