AC blows cold at night time

[lowjack]

I just found out I have a leak on the heater core hoses but I don't' think that'll affect the coolness of my ac. The day I bought it the car was really really cold. The next day it started going away with random spurts of coldness. I checked the sight glass and saw a little foam so I figured it was low. Checked the refrigerant level with a gauge and was just fine. Even added a little more r-134a, I know I should have flushed it but I was just seeing what happened.

Nothing changes, so I noticed when I drive during the night when it's much cooler my ac seems to work a LOT better. So what could be the problem?

1990 tsi awd

Also, what's the purpose of a heater core? I'm guessing just to provide heat...

 

[spawn87]

well first of all the heater core uses the coolant from the engine to give you heat during winter doesn't really have anything to do with a/c.

as for your a/c when it stops giving you cold air does it change your engine speed ( like it feels like it goes faster) ? if so it could be your a/c clutch that is starting to go bad. or it could also be the control panel has a short in the system.

not sure if that could be the problem but i hope it helps.

 

[98GSXtreme07]

I know back when I had my 97 GS and the heater core went my A/C didnt blow cold really during the day. In the morning and night it was great. A few weeks later I started to head out of my neighbor hood and started seeing smoke coming from my vents. Sometimes it was very noticeable and others the light had to hit the smoke just right to see it. Than after that, at night the entire cabin would fill up with with like fog and I was completely surrounded by the smoke/fog. All of the shops said the smoke was just because it was so humid. Wrong. I turned around and went back to one of them and showed them the leak they didn't even look at and they were like, "Yep, your heater core is gone."

$900 later and the car had great A/C and heat again. SO apparently the heater core can have something to do with it.

Of course this was a completely diferent platform but I figured I'd share my experience with the heater core.

 

[lowjack]

Hmm, dang heater core is confusing me.

Well my ecu was doing weird things, my MPI traces in the computer were shot. This is how weird it got, my AC had to be on full blast to keep the car on!

After 2 weeks of searching and gathering up money I had my ecu repaired. Now car doesn't need ac to keep car on. I know, sounds weird, but I said that because 2 post above he said a short in the system.

 

[lowjack]

Could not see any rips in the hoses but losing coolant. So why does my ac blow cold at night only?

 

[98GSXtreme07]

I'm guessing because of the night/incoming air is cooler at night.

 

[lowjack]

How much to flush refigerant and put new stuff in with dye also?