My name's Gil Bush. I've driven pass Chico, CA a few times while traveling from here in Ohio to Richland, WA (son's old residence) and then on to Bakersfield, CA (son's new residence) via Richland to Portland and I-5 South to Bakersfield. The 2009 Thanksgiving/Christmas trip was via my '86 LeRiviera. Have a good trip heading North to Oregon.
Now, here's a book for you.
As a third generation owner/operator of my family's Ice Manufacturing Plant here in Gallipolis, OH, I am somewhat "understanding" just how refrigeration works and it knowledge of this basic refrigeration principal that can help one to determine just what might be preventing your air conditioning from performing as well as you wish. It is all based on the fact that in our world converting a liquid into a gas requires heat. There is NO such thing as "cold". There is only the ABSENSE of the heat condition. It is this ABSENSE that we nickname using the word "cold". Therefore, to convert liquid water into a gas we call "steam", we have to add heat - you put it on the stove to make it boil. And the IMPORTANT fact is that the actual temperature of this liquid's ability to convert from the liquid into its gas form depends on the atmospheric pressure on that liquid which is being heated.
At our normal atmospheric pressure - the air you are presently breathing as you are reading this has a measurable "pressure" - and regular water at our "normal" air breathing pressure boils when it gets to around 212 degrees Fahrenheit.
Your air conditioner doesn't use liquid water, it uses a liquid that actually "boils" when it gets above 20 degrees BELOW ZERO IF its environment's pressure equals our atmosphere. And in your air conditioner's piping it will CEASE TO BOIL when the internal pressure rises sufficiently. And of course, when it boils it expands and "fills" up the pipes, making the pressure increase. When this "pressure" is increased sufficiently it will "condense" back into the liquid form. BUT THIS CHANGE BACK TO LIQUID REQUIRES the heat that had to be added for it to "change to the gas form" to be removed.
Thus your air conditioner is simply a "heat pump". The closed system is force filled with Freon via the room temperature of the can you bought it in being pressurized sufficiently for its internal gas to be in liquid form at our "room temperature". When it is released into your piping, it immediately expands into "gas form" since it has room to expand. This will let the can's internal pressure to continue "squirting" out. You will notice the can becoming colder. Yep, the atmosphere temperature is "boiling" the liquid in the can just like when you boil the pan of water on your stove. The can's surrounding air temperature is equal to the stove's fire to the pan of water. Remember the old "pressure cooking"? That's when one would seal the pot and this increase of internal pressure required a higher temperature to make it change into steam. This is the way your air conditioner operates. It divides your "piping" into two sections and then controls the pressure in each of the two sides.
The rule is simple. 1) Lower the pressure and the liquid boils REQUIRING it to be provided with heat. 2) Raise the pressure and it will liquefy, FORCING the heat to "go away". And if the heat doesn't "go away" it simply stays as hotter liquid at a higher pressure.
OK, now your air conditioner is "pumping" heat OUT of the "air cooler" in the coach and INTO the "air condenser" out near your car's radiator. This requires Freon liquid be available in the "air cooler". And the actual quantity that "flows" through the "air cooler" determines how much "heat" is "pumped". Remember, each ounce of water that is boiled requires a certain quantity of "heat" - measured in a thing called "BTU's". Likewise, each "ounce" of Freon also requires a certain quantity of BTU's. Thus, a sufficient quantity of liquid Freon MUST BE FED into your "air cooler" section. This is regulated by a specific valve system, the type depending on the design. It could simply be a small length of "pin-hole" size piping - it's harder to blow a large quantity of water through a pin-hole straw. And it also could be an automatic valve that opens and closes based on the measured temperature of its sensor. My LeRiviera has the "automatic valve" type system and I'd expect your to also have one. These valves are manufactured for specific sized systems AND for the TYPE OF FREON being used.
The amount of Freon required also must be properly established. Sufficient to allow the "air condenser" to build sufficient Freon in LIQUID FORM to enable the feed into the "air cooler" section to be SOLID LIQUID - meaning "fully cooled" Freon.
Your "air cooler" is your pressure cooker pot on the stove. As long as there is "water" in the pot, it will continue "boiling". And it's this "boiling" that requires heat. And that is what the heat in your motorhome's air is doing. It is "boiling" the pot. No liquid in the pot means no heat absorbed and the "pot" simply gets as hot as the "fire" - the surrounding air temp.
That is your air conditioner's problem - insufficient quantity of Freon is being "boiled" in your "pot".
And if any of these things seem "wrong", best get some outside help unless you have some refrigeration gauges and other tools. You can tell if the "outside help" knows a bit simply by watching if possible.
Good luck, 'cause it can be fixed.
Using Buick engine with Buick Air Conditioning Compressor feeding "artificial" Freon-12 to the original coach "air cooler" system and working just fine.