ENGINE FAN HIGH?

2016 AUDI A3
96,000 MILES • 2.0L • TURBO • 4WD • AUTOMATIC
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BHAMDOC1
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I just finished installing a motor on this car and still need to put back the bumper and few other things, but all connectors are back on. When I started the car the fan was on high, started adding coolant to the reservoir since there is no radiator cap, got about a gallon in. Will it change once the thermostat opens to let water flow around? temp gauge shows temperature is climbing normally, didn't keep it on long just wanted to make sure everything is running fine before I tighten all bolts back on. is there a way to bleed it/?
Aug 27, 2026 at 11:13 AM
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BHAMDOC1
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Also there is a message even car is cold, on cluster , switxh engine off and check coolant. Coolant is full and never had an issue with reservoir sensor
Aug 29, 2026 at 7:54 AM
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BHAMDOC1
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Mo heat in cabin
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Aug 29, 2026 at 8:03 AM
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STRAILER
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The best method after an engine replacement is a vacuum-fill tool, because it evacuates the air and pulls coolant throughout the system and yes, once the thermostat opens the system can be completely filled and that can be why there is no heat. I would would try to get the cooling system full before looking at the sensors. Do not let the engine sit and idle waiting for the thermostat to open while that warning is present. The temperature gauge can look normal even when there is an air pocket around part of the engine.
Aug 29, 2026 at 8:17 AM
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BHAMDOC1
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Just did a vacuum fill. I got heat now. Fan still on high with no codes related to it
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Aug 29, 2026 at 9:15 AM
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BHAMDOC1
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turned out that the ambient temp sensor needed to be connected, now all is good. thanks
Aug 29, 2026 at 12:57 PM
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STRAILER
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Nice find, thanks for letting me know.
Aug 30, 2026 at 10:19 AM
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BHAMDOC1
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Much better after water pump replacement but still goes up to 235 while driving before coming down. At idle fan is not on high anymore and temp around 225. Waiting on thermostat and thank god they changed the design where it is now on top on passenger side super easy to replace, hopefully it will make a difference too
Aug 30, 2026 at 10:34 AM
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STRAILER
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Nice work, yep the thermostat should help, but 235 might be normal before the fan kicks in. FYI.
Aug 31, 2026 at 8:21 AM
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