Accord A/C Problem Has Shop Stumped

honda
accord

#1

The A/C system in my 2001 Accord started to not work as well at the end of last summer. Now, it only works when I am going 40 mph or faster. At higher speeds, it gets really cold. At slower speeds, it just blows hot air. It was in the shop and they recharged the freon and replaced the evaporator temperature sensor. That didn’t help. It’s been back in the shop since yesterday, and they say they can’t figure out what’s wrong. I only have 81K miles on this car, and I live in DC, so I need working A/C and don’t want to buy a new car. Any suggestions, please?


#2

What shop? A good competent shop? Or an oil change / tire place?

When your car isn’t moving it depends on a fan to blow hot air off the condenser rather than the relative wind of motion.

You don’t need a new car, you need an a/c specialist.


#3

Sadly, I took it to a shop highly rated on this site. It is my first experience with them, as I have a Honda and a Toyota and have rarely needed repairs. I am surprised that they seem so perplexed, but others on this site seem to have confidence in them.


#4

I can think of two things right off the bat to have inspected, compliments of your description of the issue:

Cooling fan not working correctly.
Start there.
Make sure the condenser in front of the radiator is undamaged and clear of bugs, and the radiator itself is undamaged and clear of bugs. If the air flow of the cooling fan isn’t able to suck the air through both the radiator and the condenser, then the air coming from your vents isn’t going to be cooled very well.

Second, have the air conditioning compressor tested for how well its pressurizing the system. If its getting weak, then its not going to work very well at cooling the air. If there’s a blockage in the system somewhere, like a hose that has been pinched from crash damage, then that puts a restriction on the system.

Air conditioning isn’t a black magic.

BC.


#5

Did they check the operation of the fan and condition of the condenser fins? This seems pretty easy. When your AC is on, the fan always operates to move air over the condenser. The two things that make sense are that a) your fan isn’t kicking on when it should and/or b) your condenser needs a good cleaning or perhaps fins straightened or condenser replaced. It just sounds like one of these or both together are keeping you from getting proper air movement when stopped.

The mechanix files on this site are iffy at best. Just ask around locally for the best radiator/AC shop in your area.


#6

The evaporator temperature sensor is called the capillary bulb. This is connected to the expansion valve which regulates the amount of refrigerant that enters the evaporator. Did they also replace the expansion valve along with the capillary bulb?

Tester


#7

They only said evaporator temperature sensor, and the part cost $28. Now they say that I need to replace the car’s computer, which they say is uncommon and also will be expensive. It seems strange that if it’s the computer, this is the only problem I have. I think I’ll need a second opinion before I commit to that.

Any suggestions as to how I find an A/C specialist? I live on the border of Arlington and Fairfax Counties in Virginia.


#8

They’re guessing at it. You need to take it to someone who actually understands AC systems.


#9

For $28.00, they didn’t replace the expansion valve. And I believe that’s the problem.

The expansion valve is a variable orifice and regulates the high side pressure to the evaporator. At high engine RPM’s the compressor turns faster raising the high side pressure to the evaporator. The expansion valve opens more to to keep this pressure under check while at the same time is still able to convert the liquid refrigerant back into a gas. When the engine RPM’s drop, and the compressor slows down the high side pressure to the evaporator drops. The expansion valve then closes more to maintain the proper pressure while still converting the liquid to a gas. If the expansion valve fails to close when the engine RPM’s drop, the proper pressure to the evaporator is lost and the liquid refrigerant to the evaporator converts back to gas, or the liquid refrigerant passes thru expansion valve as a liquid, and you get no cooling from the AC at low engine RPM’s.

Tester