I drive an '03 Mazda B3000 with 58k, the AC wasn't as cold as I thought it should be so I bought a can of standard r134a refrigerant and put it is the system. Much better but I believe that there is room for more. I saw a youtube video where the guy recommended the high mileage r134a which is supposed to have some kind of conditioners for the seals in it. Anyone have any experience with this stuff? Is it better than standard r134a? Does AC stop leak screw up the system? Any info would be appreciated.

 

That's a new one on me, "high mileage r134a"

There are chemicals that can swell rubber seals and gasket, they are used in automatic transmissions that are losing internal pressure, i.e. "trans fix" or similar
They don't hurt anything, and do work, if leaking seals and gaskets are the problem, lol.

If you don't have any obvious leaks, the system was just low after 15 years, then I wouldn't pay extra for "high mileage r134a"

 

Good advice. I have no idea whether the AC system has ever been serviced. It is working very nicely now, I guess I'll just take a wait and see approach. Thanks.

 

yea mine in my 2001 needs a recharge - still blows cold but takes its sweet time getting there and even 20 min on the interstate on max ac its nowhere near as cold as it should be. Years ago when we had a 97 tarus with the 3.0 i remember if it was humid inside the car and crank the AC you could see the condensation fly outa the vents it was so cold so quick haha. literally froze in that car.

 

I used one of those cheap hoses with the gauge attached, pretty easy to add the refrigerant. I have owned this truck for about 10 months and the a.c. compressor cycled on/off quite often. Now it runs full time which I think (hope) it is supposed to do. Possibly the low pressure switch kicking in?

 

Yes, with AC on compressor would be on full time, unless pressure got too high or too low.

Cycling compressor with AC on would be pressure switch related, with AC off compressor will cycle if Defrost is selected, it is used to DRY the air in the cab blowing across the windshield so it can absorb the moisture on the windshield faster

Some later models will also shut off AC compressor if engine temp gets too high
And most AC compressors are shut off at WOT(wide open throttle) to give driver all available engine power

Just FYI, MAX AC just closes the Fresh Air Vent for the cab/cabin, so it is not having to cool the warmer outside air, it is recooling the cooler inside air.

All AC systems only have an ON or OFF, there is no "Faster cooling" compressor speed
MAX AC on later models would also close the Heater Hose Valve in the engine bay along with the Fresh Air Vent.