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Busterbvi

Heater only blowing cold

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Anyone ever had problems with the heater only blowing ambient air ?  Fan blower motor works fine so not the Hedgehog.

Coolant level OK and no air in system. Temp gauge is steady at 12 o clock.

 

Before I go ordering a thermostat or water pump I was wondering if there are any known issues with sensors etc ?

 

 

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As my fellow alcoholic said... Make sure the central dash vent is set to red dots 1,2 and 3 rather than blue cold dots ;) 

 

If not that, unless your coolant system needs a good bleed, I'm stumped :( 

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Could be the air sampler fan in the IHKA fascia is blocked with dust. The sensor is meant to read the cabin air being drawn in by a tiny fan through the slots on the fascia but if clogged the sensor is heated by the surrounding electronics instead and the climate control thinks it is already warm in the cabin.

 

Don't trust the temperature gauge on the instrument cluster too much. It is just a three position indicator: 'cold', 'probably okay' and 'too late'! Look at the hidden menu 7 and see if Ktmp rises steadily to around 96°C (from memory) assuming this is your 525i. That will help spot a thermostat that is stuck open.

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^^^

Aye, give those little slots a hoover next time you clean your car, can be full of shite!

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Worth checking the water valve which sits in the engine compartment on the passenger side. This controls the supply of water to the heater unit as part of the climate control system. I guess that if the valves have failed to open no hot water would reach the heater matrix.

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 Shortly after I bought my current 540 I found that the heaters refused to blow hot, as above, I cleaned out the little vent in the heater panel which made no difference, I also stripped and cleaned the above mentioned valves which helped, but not a lot, it turned out on my car a previous owner had put radweld or something similar in the coolant and it had clogged the heater matrix, I removed the hoses from the matrix on the bulkhead and back-flushed it with my garden hose to clear the crap out and the heaters have been toasty warm since.

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Always worth a post on here when problems arise, Hoovered the clogged vents by the cup holders and job done, now works a treat.

Never would have thought of that, thanks Beemer Guru's !

 

 

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