AC blows hot air at idle, cool air when moving.

[PulpBrah]

My sister is having an issue in her 86 where the car blows hot air at idle and cool air at speed.

A simple Google search has me thinking compressor or radiator fans , but I haven't the slightest clue how AC systems work. Any help is greatly appreciated.

[Ultramaroon]

tell her to idle the engine at 1500 steadily. The compressor doesn't keep up when it's idling.

[humfrz]

Originally Posted by Ultramaroon

tell her to idle the engine at 1500 steadily. The compressor doesn't keep up when it's idling.

In addition, suggest to her that she punch the recirc button also......


humfrz

[Ultramaroon]

Originally Posted by humfrz

In addition, suggest to her that she punch the recirc button also......


humfrz

amen. set the director thing all the way to the left so it pulls up from the footwell and blows it all out the top.

Otherwise, you get less cool air in the cabin while, in the footwell, the air gets nice and chilly from recirculating into itself.

[stevesnj]

The AC relies on air moving through the condenser, it's a thin radiator like unit in front of the engine coolant radiator. The condenser releases heat from the hot A/C system refrigerant passing through it, to the atmosphere, no hot air escaping from the condenser no or insufficient cool air inside the car. As said above turn on the Recirculate button to prevent the hot outside air trying to be cooled and force the cabin air to be cooled. It's a typical problem and nothing is broken.

[guybo]

The AC in this car is not great. It's a small engine and I think they engineered the AC system to be marginal to save a little engine power.

[steve99]

When the cars stationary at idle (or below about 60km road speed) electric fans will run when a/c compressor kicks in to remove heat from a/c and engine radiators.


If the A/C worked fine before and now its not working at idle but ok at speed it usually means low gass in a/c. As a/c compressor speeds up with engine rpm it copes a bit better with low gass in a/c. Just take it to dealer if its warrantee or an A/C shop so they can find/repair leak and re-gass

[Ultramaroon]

Originally Posted by steve99

If the A/C worked fine before and now its not working at idle but ok at speed it usually means low gass in a/c. As a/c compressor speeds up with engine rpm it copes a bit better with low gass in a/c. Just take it to dealer if its warrantee or an A/C shop so they can find/repair leak and re-gass

Do you often sit idle or move slowly in hot traffic jams? Serious question because I do, and mine has performed exactly the same way since day one.

I've heard rumor that some may have been undercharged at the factory and, if true, it may explain why mine is marginal when idling. I just figured with a high-revving engine, in order to get it to work in the widest range of rpm, they geared it to the edge at idle.

[steve99]

Originally Posted by Ultramaroon

Do you often sit idle or move slowly in hot traffic jams? Serious question because I do, and mine has performed exactly the same way since day one.

I've heard rumor that some may have been undercharged at the factory and, if true, it may explain why mine is marginal when idling. I just figured with a high-revving engine, in order to get it to work in the widest range of rpm, they geared it to the edge at idle.

I don't drive in a lot of stop start traffic , but I have not noticed the a/c doesn't work in traffic and we see 35C plus in summer, my idle is 650 rpm as well


if you hear a lot of hissing and gurgling inside the car its also an indication gass is low

[Ultramaroon]

Originally Posted by steve99

I don't drive in a lot of stop start traffic , but I have not noticed the a/c doesn't work in traffic and we see 35C plus in summer




same kind of deal with your fridge, if gass is low the freezer part works kind of ok, but the fridge section is usually warm

Yes, I know that, but an automotive AC system is VERY different from a refrigerator. There are other factors at play.

If I start out driving normally, it works perfectly. My afternoon daily commute involves stop & go immediately. It takes much longer to work if I don't high-idle it for the first 5-10 minutes. It tends to drop off when I'm at a complete standstill.

[Ultramaroon]

Originally Posted by steve99

if you hear a lot of hissing and gurgling inside the car its also an indication gass is low

Hmmm... I do. Not a gurgle but I hear it hiss a little when it cycles to keep from frosting over the evaporator. I hear the same thing in most vehicles, though.