[zvery777]

Does anyone know what a faint knocking sound might be? It's audible only from inside the cabin and in the steering wheel. If I turn the climate off it goes quiet. Thank you!

[Surly73]

Need more description to get an answer (how frequent, how loud, what pitch, sound metallic or dull, varies with engine RPM?)

But, what comes to mind for me based on what you've said is heater control valves - #5 on this diagram https://www.realoem.com/bmw/enUS/sho...diagId=64_1665

They sit near the top of the engine compartment just fore of the brake booster area. They often seem to make a "thump" when cycling on and off. This happens when the engine is up to temperature and the interior climate control is calling for partial heat. They will thump once per second or so and if the interior is quiet it can be heard and felt. Pop the hood and check these out to confirm.

This isn't an F10 thing. My E39 had the same behaviour. There's some debate whether that indicates failure of the valve or not, since it seems to continue to work fine.

[zvery777]

Originally Posted by Surly73

Need more description to get an answer (how frequent, how loud, what pitch, sound metallic or dull, varies with engine RPM?)

But, what comes to mind for me based on what you've said is heater control valves - #5 on this diagram https://www.realoem.com/bmw/enUS/sho...diagId=64_1665

They sit near the top of the engine compartment just fore of the brake booster area. They often seem to make a "thump" when cycling on and off. This happens when the engine is up to temperature and the interior climate control is calling for partial heat. They will thump once per second or so and if the interior is quiet it can be heard and felt. Pop the hood and check these out to confirm.

This isn't an F10 thing. My E39 had the same behaviour. There's some debate whether that indicates failure of the valve or not, since it seems to continue to work fine.

The sound is exactly as you described it and it happens when the engine is at operating temperature. The climate seems to work fine. Is there a way to fix this without getting a new valve? Would it fail in the future? I have been hearing it for over a year I feel like.
Thank you for your input!

[zvery777]

Replaced the heater control valve today but the thumping seems to still be there, also my front center vents blow hot air when heat is on but not the side ones (front passenger and driver). Does anyone know what this could be?

[zvery777]

Culprit found, the valve is making the noise and you can even see the top hose pulsating when that happens, could it be that the part was faulty?

[zvery777]

Bump

[Conserve]

This

https://www.amazon.com/dp/B095K73XVQ...G09PJ5Q7R4YPF9

[zvery777]

Originally Posted by Conserve

This
https://www.youtube.com/watch?v=3XvV...nel=TurboSpool
https://www.amazon.com/dp/B095K73XVQ...G09PJ5Q7R4YPF9

I already replaced the valve twice, I do get heat but still hear constant thumping sounds made by the valve. I'm trying to figure out what's causing it.

[Surly73]

Originally Posted by zvery777

I already replaced the valve twice, I do get heat but still hear constant thumping sounds made by the valve. I'm trying to figure out what's causing it.

So, uh, way back in the thread I said that multiple BMWs I've had before had valves that thumped when they were actively maintaining steady state temperatures and that it might be normal behaviour....

If you're trying to fix normal behaviour, bumping the thread isn't likely going to get you much more info. If you've replaced the valve twice and both new ones thump, and your heat is working, maybe you're done.

[zvery777]

Originally Posted by Surly73

So, uh, way back in the thread I said that multiple BMWs I've had before had valves that thumped when they were actively maintaining steady state temperatures and that it might be normal behaviour....

If you're trying to fix normal behaviour, bumping the thread isn't likely going to get you much more info. If you've replaced the valve twice and both new ones thump, and your heat is working, maybe you're done.

"Normal behavior" is what our dealerships keep telling us, but I doubt a $65K+ car was built with parts that behave that way.
I'll keep pursuing this issue and update the thread once I can get this figured out.
Thank you everyone for their input!

[Conserve]

zvery777 , Could it be air in the cooling system somehow or someway? How about bleeding the cooling system. There is no wrenching involved and it takes 10 minutes. I think its worth the try. Cheers

[zvery777]

Originally Posted by Conserve

zvery777 , Could it be air in the cooling system somehow or someway? How about bleeding the cooling system. There is no wrenching involved and it takes 10 minutes. I think its worth the try. Cheers

I did the bleeding every time I replaced the valve and not just once. I also feel like there could be air trapped somewhere. Will keep trying to get to the bottom of this!