Hi, my 'newly acquired 91 Accord's A/C isn't cooling well. It cools only down to 70 degrees. The low sider pressure reads 90 PSI while the A/C is off, and settles down to 30 psi when the A/C is on. The output line of the compressor is hot, but the input to the firewall is warm, as is the output from the expansion valve, warm. Do you think I have an obstruction? The compressor runs normal. The fans come on. When driving, it cools a little, but not like my daughter's '92, which cools down to 40 degrees at the vent. I see liquid/bubbles in the spy glass.

How would you troubleshoot where the problem lies?

Are these cars hard to convert to R134? I assume it's got R-12 in it now.

Thanks,
Ronald

 

From your description (very good), you are likely very low on refrigerant. W/O high side pressure it's not possible to be absolutely certain. Your low side pressure is OK, but not enough coolant is flowing to produce low temps. If you had a blockage your low side would be very low. The bubbles are another indicator of low charge. This means there's a leak or leaks somewhere in the system. Locations for leaks are compressor (look for oil/dirt ring on hood and nearby parts where clutch rotates), condensor (rock hit - look for oil/dirt buildup), and evaporator (requires discharge of AC system, but is easy to remove).

If no leak indications, you might consider simply adding R12 to bring cooling back. It's possible the leak is very slow and result of very long term leakage (car is 17 yrs old after all!).

Suggest getting an Accord manual (see Online Manuals links under DIY).

AC repair is not too hard, but does require 1) AC manifold gauge set and 2) vacuum pump to evacuate before charging, 3) normal diy tools

Suggest sticking w/ R12. You should be able to buy enough R12 to recharge (need to get a "license" from feds for $25 to buy R12). R12 is readily available on ebay and other locations.

Suggest reading the forums at autoacforum.com for tips on repairs, tools, procedures, etc if you plan to DIY.

good luck

 

TexasHonda, Thanks for all the good input. Where can I get a high side Honda connector/adapter?

How do I get the fed license?

When I checked the low side I noticed that the coolant had UV leak detect on it. I tested with my UV kit tonight, and couldn't find any leaks.

I've got a couple of cans of R-12 a friend gave me. I'm hoping that you're right, I just need more charge. I'll need access to the high side to assure everything is okay and safe. What kind of pressures should I see from the high and low side for a properly operating Accord A/C system?

Thanks,
Ronald

 

I thought I responded to this but apparently not. Sorry for the delay.

You can buy the high side adapter at most auto parts stores or Auto AC supply shops. ackits.com has them also.

Fed license is obtained by taking a test from epatest.com. Simple self study and open book test.

Leaks may be in the evaporator. Look for dye at end of evaporator drain tube on pax side firewall.

Low side should cycle from around 30 psi low to 45-50 psi high before compressor kicks back on. High side will also cycle w/ high pressure about 2.2*ambient air temp in degF (100F=220psi). The high side is only a rough guide and yours may be higher or lower.

I like to charge w/ doors & windows closed and car in shade, max AC, Max Fan. Allow system to run for 5 mins before noting pressures.Air vent temps should reach 35-45F lower than air temp inside the car (on floorboard), so 80F= 35-45F vent temps.

W/ R12 and a site glass you can also charge by slowing adding R12 till bubbles just stop flowing.

The fact the system has UV dye suggests someone earlier looked for a leak. System is likely leaking somewhere.

good luck