Auto A/C questions for the experts

[flatwins]

This heat is awful and I thank the air conditioners in my life daily. I know just enough about auto A/Cs to be dangerous but I'd like to keep a watch on them and help them make it through this hell of a summer.

I bought a set of gauges from Harbor Freight and was hoping you guys could give me your thoughts on the readings. Outside temp at time of reading was around 100F. Both A/Cs set on max.

First, my 2001 Nissan Frontier. Air blows cold but maybe not as forceful as I remember.

Next my 1994 Honda Civic. Air blows strong and cold for a little 4 banger.

Thanks for any suggestions!

 

[PUMPKIN]

Usually the lower the low side gets the colder it blows. What were both a/c blowing? I use a manual thermometer and install it in a vent.

 

[flatwins]

I'll measure the vent temp tomorrow. I kinda thought the high side on both vehicles look a little high.

 

[Onequickfiveoh]

This weather is bad for Ac systems period. Ambient temps over 120~ and condensers don't agree. Let's not get started on the interior temps. Hard to cool down a 140 degree cabin. Just like home Ac. Units are built to function under certain max conditions and over 112 degrees is certainly over it.

 

[tyromeo55]

Considering the high temps outside I think your liquid side ( High Side) look pretty good on both vehicles. When you took the measurements you also take a reading with the hood is as closed as you can get it. That will give you a little insight as to the fan system . The low side on the Nissan looks kinda high. Does the truck have a cabin filter that needs to be replaced or have you stuck freon in it?

 

[flatwins]

Considering the high temps outside I think your liquid side ( High Side) look pretty good on both vehicles. When you took the measurements you also take a reading with the hood is as closed as you can get it. That will give you a little insight as to the fan system . The low side on the Nissan looks kinda high. Does the truck have a cabin filter that needs to be replaced or have you stuck freon in it?

We're on the same track. I don't think the cabin filter has ever been replaced in the Frontier. Time to do that. And yes, I've screwed around and added some 134a to it.

 

[tyromeo55]

We're on the same track. I don't think the cabin filter has ever been replaced in the Frontier. Time to do that. And yes, I've screwed around and added some 134a to it.

So..... Ho much did you add? Under the hood there should be a sticker that gives a ref charge qty. Ill guess that it is a high 2# to low 3# number. If it didnt need any and you added a 12 oz can then it is overcharged by around 25%. That would be no bueno (Not that I practice what I preach all the time) The only way to really charge an automotive A/c is to make sure the supporting side of the system is all working properly and then evacuate the system and re charge with appropriate oil and virgin REF to the MFG spec. The second best way is to charge by superheat using a PT chart ( assuming it has a fixed orifice )