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Discussion Starter · #1 ·
Hi All,

I've had an issue with my AC not working on my 2017 M140i. It kicks in for a few seconds and then stops and keeps short-cycling.

I've had it re-gassed without success. The garage said it threw up error code 801224 - over pressurization of system. They recommended I have a new sensor fitted and quoted accordingly.

I thought I'd check a few things myself before having the sensor replaced. I checked the coolant levels and found the smaller RHS tank to be completely empty. When I attempted to top up, water pissed out the LHS front bottom of the car. Having spent a few hours on this forum searching, I was worried it may be radiator damage, however, there is no obvious damage but I noticed that the smaller, lower rubber hose appears to have become disconnected from the lower radiator as pictured.

My first question is, this pipe seems impossible to access from above - what is the best way to get to it?

In the meantime, can I continue to drive the car with this pipe off and the smaller coolant tank empty? (the coolant is fine in the larger tank).

Also, is fixing this likely to get my AC working again or should I still have the sensor replaced?

Cheers

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Small tank also cools the aircon system through a heat exchanger so fix the leak and the ac will return, but as said its also used for the charge cooler so I would advise against driving
 
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daft question but is coolant different between small and big tanks? I vaguely recall someone mention that they were different in colour
Nope exactly the same coolant mix. my guess it the little rad in the L/H bumper grill is damaged. BMW will charge you about 1k for the work.
 

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The left hand radiator in the bumper is part of the larger coolant tank, it's a secondary radiator nothing to do with charge cooler
 

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Discussion Starter · #9 ·
Evening All, thanks for the replies.

I attempted to get that hose back on today. I removed the airbox hose and could get the very tip of my fingers on the disconnected hose and marry up to the connector on the lower radiator (lost some skin off my knuckles in the process!). I couldn't get enough purchase to click or twist it into place so it's by no means secure.

I topped up the smaller coolant tank again and rather than pouring straight out, it was more of a trickle this time which proves that hose is the offending cause. I could hear a little pump pumping the coolant around when I turned off the ignition. I went for a 15 minute drive and was pleasantly suppressed to feel a bit of ice cold air con before it cut out again after a couple of minutes. The tank was below minimum when I returned but still some water in there.

The car is due at BMW for routine service work in a couple of weeks so I'll ask them if they can reconnect the hose correctly and test the secondary coolant circuit and AC whilst they're at it.

In the meantime, I can't be without the car so I'll fill up the small coolant tank before every journey and drive in Eco Pro mode to avoid the engine working too hard.
 

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Deffo was being awkward, 100% the same coolant in both tanks
 
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