Lukewarm heat from vent?

2013 BMW 335
118,000 MILES • 6 CYL • TURBO • 2WD • AUTOMATIC
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BHAMDOC1
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Takes forever to get some lukewarm to come out. Blower works fine; these are the codes I found. When I deleted them, I got one back which is in the picture that only shows one code (AUC). Can this affect heat? Coolant is full. I thought about the heater control valve, but I have not seen it on the driver side under the hood like most BMWs. Can you ee if there is one and where it is? Hoses to the firewall I would say are warm. I also suspect the thermostat but no codes or indications.
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Jan 14, 2025 at 10:09 AM
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STRAILER
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Does the engine get hot? If not, I would check the thermostat, but I can tell you the auxiliary water pump for the heater goes out all the time for these cars. You can remove it and put 12 volts to it and if it doesn't work, I would replace it, also check the fuse for it as well. Check out the images (below). Please let us know what happens.
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Jan 15, 2025 at 11:27 AM
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BHAMDOC1
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This says bye E92, his is the F30, the newer style. And the pictures talk about the fuel lines or filter. Where is the auxiliary pump located?
Jan 15, 2025 at 11:30 AM
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STRAILER
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Okay, my bad, here is the auxiliary water pump which can be either one, follow the heater hoses and you should be able to find it, they don't show the location. I updated the images above.
Jan 16, 2025 at 8:57 AM
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BHAMDOC1
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Can you let me know if the F30 335i has an auxiliary pump and where it is? The above is for the E92
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Jan 16, 2025 at 8:57 AM
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STRAILER
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I updated the images above. Did you see them?
Jan 17, 2025 at 11:14 AM
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BHAMDOC1
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Yes, I am able to find new and used ones online but still don't know where it is. I'll check more.
Jan 17, 2025 at 11:59 AM
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STRAILER
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Yep, I rechecked and it doesn't say where is is but it should be in the engine compartment. I would follow the heater hoses, should be connected to one of them.
Jan 18, 2025 at 10:17 AM
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BHAMDOC1
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One of the images you updated above is for a 4-cylinder, this is a 6-cylinder turbo. Heater hoses, one goes to a thermostat the other to the radiator.
Jan 18, 2025 at 12:18 PM
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STRAILER
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Maybe some one removed it? It says it is at the rear of the engine compartment. Check out the images (below). Please let us know what happens.
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Jan 19, 2025 at 9:58 AM
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BHAMDOC1
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That's the coolant pump. I verified with someone that only the M package has the aux pump behind the headlight. So am now just looking for where this heater control valve is. Strange hoses to connect to upper radiator and one to thermostat.
Jan 19, 2025 at 10:09 AM
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STRAILER
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My information says it does not have a heater control valve?
Jan 20, 2025 at 9:52 AM
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BHAMDOC1
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Weird, so what controls it? I just did a pressure test, and a common art has busted leaking, it's the use from thermostat to cylinder head, always break, and I was smelling something before, so maybe it was not holding pressure, I will replace it and see.
Jan 20, 2025 at 9:56 AM
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STRAILER
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Yep, you could also have an air bubble inside the heater core. Please go over this video, it might help:

https://www.youtube.com/watch?v=SNRb6pSwYuU

Once you get it back together, start the engine and allow it to get warm, then feel both heater hoses. Let me know what happens.
Jan 21, 2025 at 10:26 AM
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BHAMDOC1
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Yes, I saw this video bee, and I let the system bleed itself electronically 3 times, but I think the small leak that I didn't see may have contributed so once I put it back I will re-bleed it first. As far as I can remember the hoses were warm but not hot.
Jan 21, 2025 at 10:28 AM
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STRAILER
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They should be hot. Maybe the core is clogged, you might want to try to flush the core using a garden hose.
Jan 22, 2025 at 8:37 AM
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BHAMDOC1
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but if both are warm doesn't that mean the water is getting in and out of the core?
Jan 22, 2025 at 9:19 AM
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STRAILER
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Yes but if it is so little, it is not allowing the flow at all. I would check it if there were no heater control valve or aux water pump.
Jan 23, 2025 at 9:26 AM