ac discharge hose heating up???

So my A/C discharge hose on my 2008 tacoma gets very hot when i turn on my Ac is that normal? it is only when my ac is on, and it cools down when it is off, i checked my friends truck its a 2011 and it does the same. so I'm confused since a mechanic said it usually doesn't do that but wanted to see if anyone knows about that, thanks

 

I work in collision and charge a/c frequently on many different vehicles. It's normal.

 

what about the pressure what should it be at normally? mechanic said it was 400+ and it should be at 200 or something like that

 

It says the lbs or kilograms it needs to be charged at on a sticker under the hood . We just evacuate ,pressure test and charge the weight of the refrigerant required buy the vehicle . It's mostly the new stuff for us on average now the y-1234.

 

What the high side pressure should be depends on the ambient air temperature--here's a "rule of thumb" chart for low and high side pressures:



400 psi is high, here is a guide to interpreting the observed pressures:



The high side hose is normally hot, however blockage at the expansion valve or orifice tube could cause it to be very hot.

But--you need to check the low side pressure also; if it too is high then the system may be overcharged...

 

Yes, it's normal. That's how the system is supposed to work. The compressor compresses the refrigerant which increases the temperature, PV=NRT. That makes the refrigerant hotter than ambient temperature. Then, it goes through your condenser which is that second radiator looking thing in front of your radiator. It cools from air flow through the condenser then is circulated to your evaporator coil in your cab, under the dash. When the pressure drops, the temperature drops and gives you a cooler than ambient temperature in the evaporator coil. Your fan blows air through that coil and gives you nice cool, refreshing air in the cab of your truck.
Yes, it's normal.

 

Sub'd

 

400 is high. Make sure you fan is working and your system is properly charged.