I have a 2004 Honda Civic ex and I have a issue with the a/c when it’s 90+ degrees outside the a/c blows hot air I checked to see if the a/c clutch is engaged and it was. I check the fans and they were both on everything is on and seems ok but When I checked the refrigerant Level the needle went in red (warning) then when the weather cools down a little bit the a/c would kick on just a tiny bit & I check the level and it went in the yellow (warning) when it gets dark and is cool outside the a/c works perfect blows ice cold & when I check the level it’s in blue (meaning it’s full of refrigerant) not sure what’s going on with the a/c jumping to warning and back to normal blowing hot air then cold air?

  • Welcome to Motor Vehicle Maintenance & Repair! Jul 8, 2018 at 22:33

3 Answers 3


I had a related issue, the car would stop the AC in hot weather. The temp gauge on the dash would start to climb a little. I used an OBD adapter and saw that the coolant was exceeding 100C.

After some time, I found the issue. A lot of dried grass and dirt between the AC radiator and the engine radiator. This put a strain on the cooling system in hot weather.

Since its a simple job, check this first, before doing any other expensive check-ups


Go to a professional and have the AC system serviced. That way you'll have the right refrigerant charge in the system. There's no such thing as "refrigerant level", the only way of knowing how much refrigerant is left is removing it from the system and weighing it.


You probably have a very inexpensive gage, which is not super accurate.

There are two possibilities.

  1. Someone added the wrong kind of refrigerant; the system needs to be cleaned and replace with the correct refrigerant (assuming it is available)

  2. It just needs a bit more of the right type of refrigerant for the system

There are 2 different types of air conditioning refrigerant currently used in residential cooling systems. R-22, commonly referred to a Freon and R410A, a blend considered to be more environmentally friendly, sometimes called Puron. Source

Related AC Recharge- What did I do wrong?

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