overheating when ac is running
Thread Starter
Instructor
Joined: May 2006
Posts: 106
Likes: 0
From: Cary NC
Fan wont turn on while A/C is running
when i have my AC on my 84 vette begins to heat up... havnt let it get above 240 cuz i know that is getting dangerously close to overheating... also when i get up to this tempeture my AC turns HOT... im not sure if my fan is running or not while my ac is on... any thoughts?
Last edited by fsufan79; Jun 11, 2006 at 05:36 PM.
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
I believe when the A/C is turned on, the fans turn on automatically. When the A/C is not on, I believe they turn on at 220. You can easily check to see if the fans are on when the A/C is on and when your A/C is off, look at the digital temperature gauge and see if they turn on at or near 220. Let your car idle with the A/C off and the temp. will climb.
Also, check your radiator fins. They may be bent, not allowing air to pass through. Check to ensure that paper and debris has not accumulated in front of the radiator as this will definitely cause high temperatures. You may have a bad radiator cap or your radiator may be old and in need of replacement. Remove the cap and look into the radiator (make sure the car is cold). Are the rows scaled and full of dirt or are they clear and flowing freely? How old is the radiator? When was the last time you had the fuid changed? A new Dewitt or equivalent may be what you need. There are so many different things that could be causing your high temperatures that an accurate diagnosis is almost impossible without seeing the car. But start with what I mentioned and you may simply have an easy problem that you can correct.
Also, check your radiator fins. They may be bent, not allowing air to pass through. Check to ensure that paper and debris has not accumulated in front of the radiator as this will definitely cause high temperatures. You may have a bad radiator cap or your radiator may be old and in need of replacement. Remove the cap and look into the radiator (make sure the car is cold). Are the rows scaled and full of dirt or are they clear and flowing freely? How old is the radiator? When was the last time you had the fuid changed? A new Dewitt or equivalent may be what you need. There are so many different things that could be causing your high temperatures that an accurate diagnosis is almost impossible without seeing the car. But start with what I mentioned and you may simply have an easy problem that you can correct.
Thread Starter
Instructor
Joined: May 2006
Posts: 106
Likes: 0
From: Cary NC
I just checked and my fan does not come on while my AC is on... after i turn my ac off the fan will turn back on... I replaced my fan temperature switch not but 4 weeks ago and i dont think that is the problem anyways because my fan will work as long as i dont use my ac at all... Im guessing the switch that is supposed to automatically run my fan while my ac is on is broken but i dont know where that fan is or what it is..
Last edited by fsufan79; Jun 11, 2006 at 07:14 PM.
Burning Brakes
Joined: Jun 2002
Posts: 1,001
Likes: 1
From: sd
Test your fan relays to see if they are working. On my 85 there is one located on the drivers fender close to the master cylinder and one on the firewall behind the battery. On an 84 that may be different so I don't know for sure. In the factory service manual there is a procedure to check to make sure that the relay is working. They are easy to swap out and shouldn't run much more than $15 or so. Good luck!
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Fan switch on the '84 is incorporated with the compressor.
High temps with the a/c running - assuming good air flow through the condensor - is because the high side pressure is too high. So it may be overcharged or plugged up. Mist some water on the condensor and if it cools down, pull the shroud and remove any debris, stone chips etc, that is blocking air flow. If it doesn't cool down, check pressures - orifice is probably plugged up with junk.
High temps with the a/c running - assuming good air flow through the condensor - is because the high side pressure is too high. So it may be overcharged or plugged up. Mist some water on the condensor and if it cools down, pull the shroud and remove any debris, stone chips etc, that is blocking air flow. If it doesn't cool down, check pressures - orifice is probably plugged up with junk.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Corvette & Porsche 911: How Two Icons Conquered the Last 25 Years
Joe Kucinski
2027 Chevrolet Silverado 1500 First Look: Everything You NEED to Know!
Michael S. Palmer
5 Best & 5 Worst Corvette Daily Drivers
Joe Kucinski
The Headlights of Every Corvette Generation Explained
Joe Kucinski
5 Best & 5 Most Overrated Corvette Track Packages of All Time!
Joe Kucinski
Every 2027 Corvette Engine Explained
Joe Kucinski
Designer Imagines A Corvette That Looks More Like a Corvette Than the Corvette
Verdad Gallardo
10 Ugly Corvettes That We Still Kinda Love
Joe Kucinski
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
Le Mans Master
Joined: Dec 2000
Posts: 7,839
Likes: 22
From: San Diego, Ca
Yes - if it's plugged up - Get a set of manifold gages and then with engine at 1500 rpms and the main fan running, note what the low and high side pressures are plus the outside air temp. Post that info.
