Weird A/C problem

Reply Subscribe

Thread Tools

Search this Thread

May 4, 2015 | 09:20 PM

S.McDonald

Thread Starter

Intermediate

Joined: Nov 2014

Posts: 41

Likes: 3

From: Cicero NY

Weird A/C problem

99 coupe with standard (non-duel) A/C. At start up when I turn the A/C on it starts out luke warm like you would expect at start-up, but instead of getting cold, it gets extremely hot like the heat is on. It stays like this for the time I let the motor warm up a little (couple minutes). But now as soon as I drive a block or 2 it starts blowing cold and will continue to blow cold even if I get stuck in traffic. The only thing I've tried is to see how charged the system was by hooking up a refill can with a gauge on it. It read approx. 35lbs. Radiator and condensor seem clear. Car runs 195ish all the time. Im also inclined to think if it was an airflow problem it would get warm when I stop, which it doesn't. Any advice on something to check myself before I take it in to a shop?

May 4, 2015 | 10:24 PM

73Corvette

Le Mans Master

Joined: Feb 2012

Posts: 6,644

Likes: 479

From: OK

Sounds like maybe your actuator is slow to go to the correct position for cold air... not sure why it would do that, just what it sounds like to me.

May 4, 2015 | 10:37 PM

K-Spaz

Team Owner

Joined: Jul 2012

Posts: 34,479

Likes: 531

From: Central PA. - - My AR15 identifies as a muzzleloader

I believe in the Beer Fairy

On the back of the intake is the vacuum port (source) for the A/C. It goes from a rubber line to that hard plastic emmissions tubing all the way through the firewall and into the passenger compartment. It goes into the wiring harness up high at the top of the motor and stays in there till it is inside the car at the passengers footwell. That tubing gets hard and brittle. I would suspect you have an issue with that. That also goes into the right front fender and there are some vacuum Ts and a brake (check valve) in there. Those also get brittle over time and break.

I suspect that's where your issue is. There are a number of threads here on the forum which address the HVAC Vacuum issues. Several are very well documented, I even did one myself if I recall correctly. Search for them. The fixes are cheap and easy, but not particularly fun.

And grab your codes and post up what they are. All of em.

Last edited by K-Spaz; May 4, 2015 at 10:42 PM.

May 5, 2015 | 09:15 AM

K-Spaz

Team Owner

Joined: Jul 2012

Posts: 34,479

Likes: 531

From: Central PA. - - My AR15 identifies as a muzzleloader

I believe in the Beer Fairy

Post up your codes and they should tell you what the problem is... If they don't pinpoint it, what they don't tell you will probably tell you something.

There's actuators that are motor driven and dashpots that are vacuum. and there are doors on each.

May 5, 2015 | 09:18 AM

73Corvette

Le Mans Master

Joined: Feb 2012

Posts: 6,644

Likes: 479

From: OK

The vacuum actuators have nothing to do with temperature. The vacuum dampers just control air flow thru various vents:

recirc/vent, floor vents/upper vents/defrost

The HEAT & COOLING are controlled by the ACTUATORS.

May 5, 2015 | 11:43 AM

jimcork1

Drifting

Joined: Jan 2001

Posts: 1,347

Likes: 4

From: Slidell La

Use gauges check Freon. Mine was low after 10 yrs and had never added. My discharge was 180 and suction 28. I added enough to get to 230/34 at 80 F and all is well.

May 5, 2015 | 09:32 PM

S.McDonald

Thread Starter

Intermediate

Joined: Nov 2014

Posts: 41

Likes: 3

From: Cicero NY

Thanks for all the advice, but I may have found my problem. Tonight I started the car and turned the a/c on. It blew hot/warm air and the low pressure line was warm until the engine reached 185 and the fans came on. Once the fans came on, the line got cold and the vents started blowing cold. I believe my condenser is dirty even though I can't really see any trash on it. I've watched a few videos on cleaning the condenser but I'm up for any advice I could get to do it the easiest/best way.

May 5, 2015 | 09:45 PM

73Corvette

Le Mans Master

Joined: Feb 2012

Posts: 6,644

Likes: 479

From: OK

If the condenser fins are packed off with crap... so is the radiator. It is very simple to PULL the radiator out...then you can actually, really, clean them both... you will be glad you did.