Plugged heater core. BMW F32 435i

BMWTurboDzl

Thread starter
Joined
Apr 15, 2010
Messages
8,726
Location
Atlanta,GA
My vehicle developed a no heat condition and I think I've narrowed it down to a plugged heater core. There's a heater control valve on the inlet hose which controls the amount of heated coolant making its way to the heater core. My diagnosis is based upon the fact that the inlet hose between the control valve and the heater core is warm which leads me to believe that the control valve is functioning. The outlet hose is cold.

I'm wondering what sort of experience people have flushing the core only OR whether you guys think it's easier to just use a cleaner flush on the entire system?

Recommended products? Liqui Moly, Motul, and others have a 500 ml "pour-n-idle" product.

My engine (N55) has an electric water pump and I don't have a block drain so I don't know how I would flush out any cleaner.

UPDATE: 63k miles on the odo. 2015 MY
 
Last edited:

BMWTurboDzl

Thread starter
Joined
Apr 15, 2010
Messages
8,726
Location
Atlanta,GA
VERY unusual to have a BMW with a blocked core. Are you able to scan the vehicle for BMW fault codes?
I'm unable to pull BMW fault codes. As others have said it could be the heater control valve (p/n# 64119254742). I guess I could replace it ($200) I would think if the part failed it would fail closed and I would have no hot coolant making its way to the heater core.

I've read that sometimes BMW will ask you guys to do a software reset but would that fix a lazy HCV?

Sounds like a trip to the repair shop.
 
Last edited:
Joined
Apr 3, 2017
Messages
3,081
Location
Ontario, Canada
I'm unable to pull BMW fault codes. As others have said it could be the heater control valve (p/n# 64119254742). I guess I could replace it ($200) I would think if the part failed it would fail closed and I would have no hot coolant making its way to the heater core.

I've read that sometimes BMW will ask you guys to do a software reset but would that fix a lazy HCV?

Sounds like a trip to the repair shop.
Could also be a blend door issue (stuck blend door, bad servo motor) in the heater box. Could also just be a broken wire going to the water valve, as it is electronically operated, or a bad IKHA module. Could even be a bad electric water pump. Could be so many things.....
 
Last edited:
Joined
Mar 8, 2012
Messages
16,972
Location
Colorado Springs
Owning an out of warranty BMW, first order of business is to get a scan tool that can read BMW faults. At least that gives you a solid place to start.
@BMWTurboDzl Get Protool and K-DCAN cable from bimmergeeks. Excellent software that is basically INPA and ISTA translated into common language. Does not have all INPA and ISTA functions but codes and reads everything.
Or you could download INPA and ISTA+ and run your own diagnosis, but you need K-DCAN again.
 
Joined
May 17, 2021
Messages
1,800
Location
open range
.
#3/11 is the valve mentioned and that's where you perhaps could disconnect the hoses:


308133.jpg



I'd advocate to follow MightyMouseTech's recommendations first though.
.
 
Joined
Apr 13, 2013
Messages
9,007
Location
FL, USA
It can on VW, but I personally never heard on BMW.
And No.1 cause on VW are dealerships running that BG garbage to flush system.
Unfortunately I am afraid that is exactly what happened. It was in for a water pump replacement around 35K miles and they used some type of flush product. 15K miles later we had a plugged heater core. I was able to get VW to pay for half of the repair.
 
Joined
Mar 8, 2012
Messages
16,972
Location
Colorado Springs
Unfortunately I am afraid that is exactly what happened. It was in for a water pump replacement around 35K miles and they used some type of flush product. 15K miles later we had a plugged heater core. I was able to get VW to pay for half of the repair.
Yep. I took Tiguan for water pump recall. SA tried to sell me BG flush. I told him to put in capital letters to not do it under any circumstances as it can clog. SA answer? “Yeah, that happens!”
They know it is an issue and they still sell BG garbage.
 

BMWTurboDzl

Thread starter
Joined
Apr 15, 2010
Messages
8,726
Location
Atlanta,GA
@BMWTurboDzl Get Protool and K-DCAN cable from bimmergeeks. Excellent software that is basically INPA and ISTA translated into common language. Does not have all INPA and ISTA functions but codes and reads everything.
Or you could download INPA and ISTA+ and run your own diagnosis, but you need K-DCAN again.
I've been playing with the APP and it looks slick but I've been thinking that might as well try to get ISTA+ and INPA as I have an old laptop (Win95) around the house.
 
Joined
May 9, 2014
Messages
2,193
Location
Minnesota
My vehicle developed a no heat condition and I think I've narrowed it down to a plugged heater core. There's a heater control valve on the inlet hose which controls the amount of heated coolant making its way to the heater core. My diagnosis is based upon the fact that the inlet hose between the control valve and the heater core is warm which leads me to believe that the control valve is functioning. The outlet hose is cold.

I'm wondering what sort of experience people have flushing the core only OR whether you guys think it's easier to just use a cleaner flush on the entire system?

Recommended products? Liqui Moly, Motul, and others have a 500 ml "pour-n-idle" product.

My engine (N55) has an electric water pump and I don't have a block drain so I don't know how I would flush out any cleaner.

UPDATE: 63k miles on the odo. 2015 MY
How do you know the valve to the heater core is open? How do you know the door that directs air over the heater core is properly actuated? And finally, is there enough coolant in the system. A small amount of missing coolant will leave an air bubble that can, on some cars end up in the heater core. It will act as very poor heat levels. It happened on my Pontiac Vibe last month. No one on this site believed me but adding 4 ounces of coolant and burping the system fixed the issue. I doubt you have a clogged heater core.....remember the heater core itself does not hold much fluid so a 4 ounces of air is significant.
 
Top