Sorry for such a general question as my first post but I am trying to use some ac pro on my 2018 300 and I've found the ports, right side, thicker pipping...feel free to correct me if this is wrong.

But onto my question no matter how much force i use the ac pro connector wont go on the pipe... I thought these connectors were universal, can any one confirm? Ive done this once before on a 2015 mustang and it went on easy....I cant see if anything is in the hole blocking it but that was be surprising to me and yes I did take the cap off

 

A/C PRO WILL NOT WORK in your vehicle! It is R-134a refrigerant while your vehicle uses the NEW Y1234a refrigerant, and as such the High and Low pressure ports are different sized to prevent mixing the two types. Just like when they changed years ago from R-12 to the R-134a.

 

And just so that you know, the refrigerant that you do need for that car is currently selling for $70.00 per pound. That is not a typo in the price, the crap is that expensive..
That means that the average car, which requires 3 pounds of refrigerant will cost $210.00 dollars just for the refrigerant to recharge it.

The high price is because all of it is going into the new cars, and since new cars do not leak refrigerant there is no need for smaller retail cans of it.
Amazon has it from the very very few sources that have bothered to put it into smaller containers, but they get to set the price because they have no competitors in the market for it.
It takes 1234yf refrigerant.

 

Oh, and why do you have to recharge a 2018 300 anyway?
If you are experiencing a situation where the air does not seem to be cooling the vehicle while recirculate is on, during a long trip, you are freezing up the system.
Turn off recirculate when on long trips.

 

Not to "bash" on the original posting member..as this is not the first time I've run across this same question, But goes to show the power of advertising media on novice DIYers. One has to look and find out just what their particular year vehicle requires for such things, there ARE notice tags in the engine compartment or on the underside of the engine hood.
And YES running in constant recirculation mode can do as was posted. Also prolonged running of the a/c while parked will NOT get as cold, as when in forward motion of driving in certain temp ranges, even when the radiator fans are running as they should.