Air conditioning conundrum

I have a 2002 Honda CRV with 68,000 miles on it. 9 months ago the AC went out and had entirely new system put in (compressor, etc.). 10 days late (no exaggeration here) the AC went out again. took it back and mechanic said the compressor died and he put in a new one. The AC has worked fine since then.

Today on the highway i noticed the AC was blowing warm air. this continued until we slowed down at a stop sign, and then it gradually got cooler. I noticed this is definitely a pattern where the AC works fine at stop or slow speed (up to 30-40). but on highway it blows hot air (70mph).

Any ideas what the problem is here? could the new AC system that’s only 9 mo old be bad already? Or is it something different.

Check to make sure the fans on the radiator are working properly. Check the fluid level in the radiator.

Sometimes the compressors disintegrate and require much more work to get out all the shrapnel. The cheapest job might not be the best job.

Thanks for the quick feedback. Never thought it could be the radiator.

Waterboy - i sure hope this isnt due to shoddy labor. The AC replacement was not cheap at all, and my very trustworthy mechanic highly recommended this shop.

There are several possibilities, assuming the initial repair was done properly with a thorough system flush, accumulator replacement, etc.

One could be a blend door problem. The blend door opens and closes to provide heat from the heater core and if the door is opening on the highway the heat could be overriding the cold evaporator.

Another could be a pressure switch problem which could be cutting power off to the compressor at elevated RPMs, as in highway speeds.

The part about the first compressor dying does raise a bit of a red flag. It would be interesting to know WHY it died. The usual cause of death is either a faulty remanufactured unit or an installer problem; as in not flushing the system out, replacing the accumulator, etc.

i don’t know why the first compressor went out last august, but the 2nd one (that only lasted for 10 days) was a honda part, and i was told it seized. Just got a bad one. Now i’m wondering if that was true or not.

i do know when i had it replaced the first time, they replaced the compressor, clutch, drier, etc.

There’s really about only one reason for a Honda compressor to seize up and that’s because it had no oil, or not near enough oil, in it.
Maybe someone made the assumption (always a bad thing) that the compressor had sufficient oil and simply stuck it on there. Some compressors come with oil in them and in my experience the majority do not.

If the second compressor seized up due to lack of oil this means the flushing process, drier, etc. should have been repeated.

At this point, about all I could recommend is having the system pressures checked, and at elevated RPMS, to weed out any problem there.

These “blows fine then slowly gets warm, then slowly returns to nominal function” posts make me think of evaporator icing