A/C Blows hot
Le Mans Master
Joined: May 2005
Posts: 7,913
Likes: 2,060
From: Cypress TX
It must be related to underhood temps. I've had it cut out after the car was sitting in the hot sun and the coolant temps were only reading about 218. But then I got it up to 238 while doing spirited driving in 100+ degree, humid temperatures, and it never cut out. As long as the car is moving, it seems to work fine.
I have heads/cam and uncoated headers. That makes it pretty hot under the hood, especially when it's over 100 degrees with high humidity. I would highly recommend anyone in this climate to coat the headers unless you spring for a vented hood.
Side note, the cooling fan if it cuts out will also kill the A/C. I had that problem, too, until I direct connected the ground line to the cooling fan. The connector was starting to melt and it wasn't making good contact.
I have heads/cam and uncoated headers. That makes it pretty hot under the hood, especially when it's over 100 degrees with high humidity. I would highly recommend anyone in this climate to coat the headers unless you spring for a vented hood.
Side note, the cooling fan if it cuts out will also kill the A/C. I had that problem, too, until I direct connected the ground line to the cooling fan. The connector was starting to melt and it wasn't making good contact.
Last edited by VetteVinnie; Aug 5, 2010 at 09:53 AM.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
Underhood temps do play a part. I had my AC gauges hooked up and was looking at vent temps. I was able to get them down to 60. I took the gauges off and closed the hood and by the time I got in the car the vent temp was up to 65. But I really think its airflow through the condenser that is the issue. Because we remove the OEM front radiator shroud to install our centri kits the air that the fan is pulling through the radiator can easily go around the condenser rather than through it. We are not removing enough heat fom the refrigerant so vent temps go up. If it gets real bad then high side pressures go up and the high pressure cutoff kicks in and it gets really warm really fast.
Last edited by 5 Liter Eater; Aug 5, 2010 at 11:48 AM.
Melting Slicks
Joined: Apr 2005
Posts: 3,418
Likes: 1
From: Chicagoland Area IL
Underhood temps do play a part. I had my AC gauges hooked up and was looking at vent temps. I was able to get them down to 60. I took the gauges off and closed the hood and by the time I got in the car the vent temp was up to 65. But I really think its airflow through the condenser that is the issue. Because we remove the front radiator shroud to install our centri kits the air that the fan is pulling through the radiator can easily go around the condenser rather than through it. We are not removing enough heat fom the refrigerant so vent temps go up. If it gets real bad then high side pressures go up and the high pressure cutoff kicks in and it gets really warm really fast.
a few days ago, I drove car with shroud off (running late so didn't have time) and it was the first time I had hot air blowing... With my car I could anticipate it by watching voltage gauge, as soon as it got below 12.2V hot air. That's how close to edge fan is... I had laptop with me and bumped idle up 100RPM just for grins and that got voltage to dip less at red lights... NOTE this was just a test... cleaned everything, put shroud back on and dropped idle back to normal. I think predominent factor is air flow and correct shrouding.
Mike
Instructor
Joined: Feb 2010
Posts: 244
Likes: 0
i had this exact same problem, when i sit at idol for more than 10 min the a/c blows hot... once i start moving and get the car rolling after 1 to 2 minutes it blows cold... my car is super charged as well and has LT headers. I was cursing like a **** cuz it was hot yesterday.... it got to a point where it didnt come on at all on the drive home, i woke up this am drove to work and it blows ICE COLD... im stumped
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
This weekend I'm going to look at putting some weather stripping in between the condenser and radiator. This way, whatever air the fan is pulling in has to go through both the condenser and radiator. Originally I was going to look into making a shroud kind of like the pieces that come with Andys kit but then I thought about what I wanted to accomplish and this seemed easier. At least for a test.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
So my problem turned out to be mostly that the recirculation door was not working...Prior to finding that out I had removed and cleaned out my condenser and radiator and put some weather stripping on the sides of the condenser between it and the radiator which didn't help. After fixing the recirculation door and lowering my AC charge pressure to spec it's fine now.
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Racer
Joined: Mar 2003
Posts: 277
Likes: 4
From: Halfmoon New York
Racer
Joined: Mar 2003
Posts: 277
Likes: 4
From: Halfmoon New York
Side note, that piece between the radiator and the air dam supposedly assists with aerodynamics and helps reduce lift in the nose. I plan to run a Katech splitter with their undertray at some point, so I am looking for different solutions (including the possibility of ditching the Vararam and going with a Killer Bee II).
Check this thread and check your connector:
http://forums.corvetteforum.com/c6-t...d-working.html
Le Mans Master
Joined: May 2005
Posts: 7,913
Likes: 2,060
From: Cypress TX
Don't get me wrong, the Vararam pulled hard when I first got it installed. There was a noticeable seat of the pants difference. But even last summer before heads/cam, I was having a problem with the A/C blowing hot. Between fixing the ground wire on the fan connector and changing out to the Callaway, that problem appears to be resolved for good.
Racer
Joined: Mar 2003
Posts: 277
Likes: 4
From: Halfmoon New York
No, ended up going with the Callaway. Works great and actually looks factory. Big difference on cooling. Dropped on average 15-20 degrees on coolant temps, and I can let it cook at idle all day in the 100+ degree heat and the A/C will never shut down like it did. It was also blocking the A/C condenser.
Don't get me wrong, the Vararam pulled hard when I first got it installed. There was a noticeable seat of the pants difference. But even last summer before heads/cam, I was having a problem with the A/C blowing hot. Between fixing the ground wire on the fan connector and changing out to the Callaway, that problem appears to be resolved for good.
Don't get me wrong, the Vararam pulled hard when I first got it installed. There was a noticeable seat of the pants difference. But even last summer before heads/cam, I was having a problem with the A/C blowing hot. Between fixing the ground wire on the fan connector and changing out to the Callaway, that problem appears to be resolved for good.
Le Mans Master
Joined: May 2005
Posts: 7,913
Likes: 2,060
From: Cypress TX
Yeah, pretty much my comments re: Vararam pulling through. I like the idea of the cold intake so I was considering the bee with the shroud. These really seem sensitive to the whole shroud thing. Any other particular reason for the Callaway? And did you really see a drop in the sotp performance (I'm stock, no cam, so that might be an unfair question) Thanks again.
But you can't use these numbers as comparison to yours since mine is far from stock.
Le Mans Master
Joined: Aug 2002
Posts: 8,472
Likes: 38
From: Houston TX
St. Jude Donor '11
The recirculation door is what actually moves when you change the AC from fresh air to recirculated. You can check it by removing the cabin air filter under the hood. When the HVAC is set to fresh air you should be able to see the squirrel cage of the blower motor. When you put it to recirculated the door should close off the hole. If it doesn't it may be out of calibration like mine was. First try recalibrating all the doors by removing the battery power for at least 60 seconds (you can alternatively remove the HVAC fuse(s) in the passenger kickpanel but there are more than one and I'm not sure which one it is). If that doesn't fix it then remove the bottom panel of the passenger dash (three large push pins) and remove the blower motor (three small screws). Then you can see the door and actuate it at the same time. If it's not moving then take the motor off (two small screws) and see if it operates on its own. If so then set the recirculation button to whatever the door position is. re-install and see if it works. Mine did.
Racer
Joined: Mar 2003
Posts: 277
Likes: 4
From: Halfmoon New York
The recirculation door is what actually moves when you change the AC from fresh air to recirculated. You can check it by removing the cabin air filter under the hood. When the HVAC is set to fresh air you should be able to see the squirrel cage of the blower motor. When you put it to recirculated the door should close off the hole. If it doesn't it may be out of calibration like mine was. First try recalibrating all the doors by removing the battery power for at least 60 seconds (you can alternatively remove the HVAC fuse(s) in the passenger kickpanel but there are more than one and I'm not sure which one it is). If that doesn't fix it then remove the bottom panel of the passenger dash (three large push pins) and remove the blower motor (three small screws). Then you can see the door and actuate it at the same time. If it's not moving then take the motor off (two small screws) and see if it operates on its own. If so then set the recirculation button to whatever the door position is. re-install and see if it works. Mine did.
Instructor
Joined: Oct 2012
Posts: 200
Likes: 1
I need to bump this thread back from the dead. I have a s/c car and when it is extremely hot outside the ac stops working. I have no leaks, the proper amount of refrigerant 1.1 lbs , the fans kick on full blast with the AC. I can tell it is from the engine compartment being too hot and the inter-cooler blocking the condensers path. This mix basically makes the high side too hot and shuts off the compressor. I see others have had this problem. What is the best solution...Header wrap the AC lines so the heat from the headers don't soak it (mine are Kooks and coated), relocate something, or buy better fans? Is the trick really to release some refrigerant from the system? I already tweaked the fan settings with HPT also. Any help is appreciated.
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 1,231
Likes: 1
From: Paramus NJ
I need to bump this thread back from the dead. I have a s/c car and when it is extremely hot outside the ac stops working. I have no leaks, the proper amount of refrigerant 1.1 lbs , the fans kick on full blast with the AC. I can tell it is from the engine compartment being too hot and the inter-cooler blocking the condensers path. This mix basically makes the high side too hot and shuts off the compressor. I see others have had this problem. What is the best solution...Header wrap the AC lines so the heat from the headers don't soak it (mine are Kooks and coated), relocate something, or buy better fans? Is the trick really to release some refrigerant from the system? I already tweaked the fan settings with HPT also. Any help is appreciated.
Instructor
Joined: Oct 2012
Posts: 200
Likes: 1
I need to see a pic of this notorious fan module and what people do to fix it.
Wrapping some of the lines with header wrap wont help any?
What is the normal pressure for the hi/low side line and what is the cutoff point for the high side?
Wrapping some of the lines with header wrap wont help any?
What is the normal pressure for the hi/low side line and what is the cutoff point for the high side?
Thread Starter
Burning Brakes
Joined: Oct 2009
Posts: 1,231
Likes: 1
From: Paramus NJ
I don't know the exact pressures. Consult your tuner and have him make the adjustments. As far as the fan module my tuner deleted the module altogether and hard wired the fans.