My 97 accord ex coupe was not blowing cold air any more. I believed that the compressor was on it's last leg due to the fact that there was a slight noise when it came on. I ordered a new Denso compressor & proceeded to replace the unit. I filled it with the appropriate amount of oil, replaced/oiled the o-rings, & buttoned everything up. I did purchase a new drier & thermal expansion valve @ the same time as the compressor to ensure Denso would honor the warranty on the compressor. I didn't, however, install them based on the advice of a friend who has been a certified hvac tech for 20+ yrs. He said it wasn't necessary since the system would only be open for a short period of time & that replacing them could just introduce leaks to the system.

I pulled vacuum on the system for over 3 hours (better safe than sorry). Then left the gauges on for about an hour to ensure there were no leaks. I then charged the system with the correct amount of r134a (22.9oz). My pressures on a 100+ degree day were 42psi low & 200psi high. The temp @ the vents was only approximately 5 degrees cooler than ambient temp.

I then consulted my hvac friend again, who told me that maybe due to the high ambient temp on the day I charged it, that I should recheck my pressures on a cooler day & if low, add additional r134a. I did so yesterday & as I expected, with the ambient temp around 78 degrees, my pressures were 35psi low & 150psi high. These numbers seemed low to me, so I figured I would add additional r134a. This may have been the wrong thing to do, but I figured it was worth a shot. the system took another approx. 10oz & the pressures came up to 39psi low & 200psi high. After this there was no change to the vent temp (still approx. 5degrees lower than ambient). I left the gauges on with the car running & ac on max just to monitor the gauges to see if there were any changes to pressure. After about 15mins I noticed the high side slowly rising. It went almost up to 300 psi on the high side. The low side remained @ 39 psi. I don't know if this is normal or if it is some indication of what my problem is, but I thought I should mention it.

I'm not sure what my next step should be. Should I go ahead & replace the drier & tx valve? Any suggestions would be greatly appreciated. As I would hate to have to take it to a mechanic after doing all of this work myself. Plus I am stubborn when it comes to paying someone to do something I should be able to do myself. Thanks

 

by the book, replace the dryer. it keeps stupid **** from ruining the efficiency of the system. that and they are usually like $20. just do it. as far as leaks.. you can replace the o rings to help, but it's a game of chance. either way, leaks won't hurt your cooling unless all your refrigerant has leaked out.

next check for any kinks in the lines. any kink will cause shitty efficiency.

are the condenser fans working? make sure they are. also make sure the condensor isn't covered in bugs and ****. might want to do the same for the evaporator. i don't think the accords had a cabin filter but i don't know. might be worth it to see if leaves and **** are covering the evaporator.

 

I agree that the helms says to replace the drier, but I was going with the advice of a licensed hvac tech. I figured that was gonna have to be my next step, but do you think a bad drier would cause the problem I'm having?

And... yes the fans are working correctly. I recently had to replace my radiator & when I had that out, I removed all the debris from the condensor (wasn't much). I haven't looked @ the evaporator, but I guess it's worth a shot as long as I don't need to evac the system to see in there. Thanks for your suggestions.

 

Anyone else? Is there anything that can be determined by the increase in pressure on the high side?

 

Putting the extra 10 oz was not a good thing to do. The system is now overcharged. When the high side pressure is to high the probable cause could be that its overcharged, condenser plugged before the refrigerant turns to liquid, poor air flow across the condenser, fan clutch slipping. could also be mixed refrigerants or air in recovery machine or tank.