It strains any impurities from the coolant.
Originally this car had R12 refrigerant. It may have since been updated to accept R134a. The coolant/radiator system is not part of the air conditioning system. But the hot antifreeze-coolant is used for the heating system...
Don't confuse engine coolant and air conditioning refrigerant. Engine coolant is Dex cool- Do not use any other kind as the sensors in the system will read differently with the wrong coolant and make incorrect adjustments in your system. Air conditioning refrigerant in your car is R-134a.
If you need to purchase a replacement filter for your air conditioning system, you need to know what sort of condition your air conditioner is in. If you can find a trusty repairman, see if you can get advice on whether or not you should get a new filter.
I believe that the coolant system capacity is 8.6 quarts ( 8.1 liters ) for your Explorer ( if it has air conditioning )
Put a filter system on it! Some types have inline filters for them, not the huge filters.
I'm new to this site and not sure of the system yet. Is there anyone there?
The filter is on the top inboard side cf the fuel tank.
replace the cabin filter
Possibly (And probably) the coolant gas has leaked out due to a tiny hole somewhere in the system. You need to get it checked properly before refilling the coolant.
Probably low on coolant. Re-charge the system then check again.
There are two schrader / port valves to the air conditioning system. One will be a high pressure and the other will be a low pressure. You need a certified mechanic to check and refill the system. You can not simply refill the system.
The best brand of air conditioning system for you depends on a variety of factors. For example, do you live in an apartment or do you own your own home? Do you have any allergies that would require a special filter? An air conditioning system should be purchased with these questions in mind.