93 Accord AC question

I am going to look at a 93 accord tomorrow. The owner says the AC blows warm. What is the common cause of this?

Also, does this year use R-12 or R134a??

THanks

No freon in system, leak in freon piping, blown fuse (no.7) 7.5A, bad ATU. Does the compressor clutch engage? If it is out of freon, the clutch won't engage. You can check system pressure by hooking a guage to either the inlet or outlet fittings. You can short the pressure switch and see if the clutch engages with A/C selected. I think the system uses R-12 unless somebody converted the system to R-134. You can check by looking at the low/high pressure inlet fittings.

Depending on the problem (and for a '93 it could be a bunch of things) it could turn out to be VERY expensive. If it turns out to be the compressor, figure several 100 dollars, IF you do it yourself.

If it's general old age with compressor, evaporator (and maybe line leaks like I had) a shop might quote you anytning up to $2500.

Update: I finally went and looked at the car. 158k, great shape, some issues, but I feel it worthy of the $1000 the owner was asking, so I bought it.

Interesting thing is that the car has been converted to R-134a. I've heard this can be hard on R-12 inteneded compressors. Whether or not that is true, what could I expect to pay for a compressor?

The R-12 vs R134 deal is that R134 doesn't cool as well as R-12. It has no effect on the compressor, however, you use a different oil with R134 and the R12 oil isn't all that compatible. So if everything was done correctly in purging the system before the introduction of R134 and R134 oil, the system should work but not as well as with R12. You need to see if there is pressure in the system. No pressure-the clutch won't engage.

I haven't had any problem with 134a upgrades. they cool as well as Freon. Early on, they used to say that when you retrofitted, you had to use a slight undercharge of 134a vs R12 due to different expansion rates and the possibility of system damage.

Later it was found that usually the cause of expansion damage was from improper evacuation prior to charging with 134a, contamination with remaining R12 or air in the system, coupled with congealing of unconditioned compressor oil being responsible for the unpredictable results. The new retrofits just use a conditioner oil charge that makes the PAG oil in the R12 system compatable with 134a properties.

Now many sources indicate a slight OVERcharge with 134a, about 5% or so, will give correct system pressures and performance.

On some really old systems, internal compressor wear also caused the 134a to not work real efficiently after retrofits. This would lead to unusually low suction side pressure, causing the low pressure switch to force compressor cycling, and the vent temps were unstable and not very cold, obviously.

I had a '77 one owner Ford LTD that's A/C system had never been compromised, and worked like new. When it developed a condensor leak, I decided it would be a good time to retrofit to ease future service costs.

After changing over, I could get vent temps as low as 25 degrees F on the highway. You could see your breath if you put your face near a vent! I actually had to bleed off some charge, as the evap core would ice up on humid days.

That car is still being driven daily, and the owner tells me the A/C will still run you out.

If you find the compressor is bad, you might want to look into obtaining one from a 134a equipped model in a salvage yard, they are somewhat more efficient than the R12 counterpart.

The last one I did was a '79 Chevy with a compressor that you could hear the guts rattling when it ran. I got a 134a compressor off a '96 Blazer in the boneyard for $25, direct fit and worked dynamite.

Knowing what Honda compressors cost for new or reman, you won't get a deal like that, but it'd still be cheaper, I bet.

You just gotta be real careful that you get the exact same type, Honda used lots of different ones, sometimes on the same model and year.

this is something I'm really interested in. How do I know which compressors will work for my 93 accord?

do I just assume that a compressor out of any newer 4 cylinder accord model will work?

And what about the wheel that mates with the belt (I realize that isn't the right term for it). Are they removable like on alternators?

thanks!

The pulley on the A/C compressor is a strange assembly. The pulley itself rides independantly on it's own bearing, so it turns idly when the system is off.

Then there is an electromagnetic clutch, when power is applied, it snaps a plate solidly against the pulley, just as a car's clutch plate is clamped against the flywheel by the pressure plate when you let the clutch out. So the pulley is actually a pulley and a flywheel.

Disassembly requires special tools and know-how. The only reason you'd want to do that is if the clutch were burnt out for some reason, or there were a leaking front seal causing it to slip or loose refrigerant.

Either way, most shops would rather just replace the whole compressor than fool with trying to repair the existing unit.

What I said about finding the right one, I remember form working in a parts dept, we'd have someone order an A/C comp for a Honda Civic or Accord, and it might list 3 possibilities for that model/year.

We would usually just get them to send it up to us so we could physically match it, and verify they were getting the right one. Another one might look very similar and even be the same manufacturer, but have subtle differences that didn't become apparent until the tech would try to install it.

Lots of times we'd have three different possibilities and STILL not have the right one, and have to get it from a dealer or A/C supply warehouse.

I just don't want you to end up buying a used or reman unit that you can't return.

There is so much mechanic-error and misdiagnosis returns on A/C compressors, some companies are really cracking down on warrantee. Some require documentaion that the reciever/dryer (a filter) was changed and the system was flushed before the compressor was installed.

This is because when one starts to go bad, it usually is pumping metal shavings into the system that destroy the new compressor pretty fast if not removed from the system. They take one look into the returned compressor and see a bunch of metallic debris...no warrantee.

the second most common installer error is failure to add the recommended amount of the correct type of refrigernat oil into the compressor before running it. Lots of those come back siezed, and they won't take it in return.