Hello my 2000 mercedes e 320 have a weird a/c problem that i cant figure out, in the morning the ac preforms normally, vaules on climate control (driving) #3- 48 #4- 49 #5 -51 #7- 9 afternoon reading at idle #3-102 #4-85 #5-107 #7-15 please help me i dont understand what could be the problem, in the afternoon those numbers will lower a little and cabin will cool off a little, passenger side more cooler than drivers side afternoon only, morning no problem please help me thank you.

Sounds like it may be a little low on refrigerant

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Jim

Thanks for the reply, thats what i thought, question? on a 100 degree day i check the low side with my gauges its reading 45 psi, should add more freon? if so whats the max psi low side on a 100 degree day without over charging.

You got to watch the high side too. Add enough to make it blow cold all the way accross the dash. Sounds like it is slightly low. Best way is to evacuate, vacuum and re-charge with the measured amount.

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Jim

It’s nigh impossible for a simple pressure test to show anything meaningful.

You need both pressure and temperature readings on high and low side lines, the motor needs to be above 1500RPM, and the system needs to be on high cool, with windows open, and a large fan blowing in front of the car…

45psi sounds full, but if at idle rpm, could be totally low.


A lot needs to be happening to get good refrigerant numbers…

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Thank you all for the help it was low on freon