Air blows cold when driving but not when idle

 

Could be a low charge. I'd check the pressures. Make sure the belt is tight, no debris in front of the condenser, and the fan clutch is working properly also.

Did you ever solve your gas consumption problem?

 

Going to have mechanic charge the air conditioner this week. Also just checked gas mileage and I’m satisfied. 10 in town and 16 on the highway. We put some kind of overdrive on the back of the tranny so that’s why I’m getting 16 on the highway. Also checked the odometer on the highway today and it was dead on.

 

Airfreon is up to specs. He checked the temp on the cold Freon line on the condenser 58 degrees plenty of air flow but the temp at all the air vents is 76 degrees. Doesn’t make sense to me

 

Ok, my 76 corvette has a new stroker in it . All the air conditioner parts are new except the controls in the inside panel and the condenser. I have changed the fan relay 3 times. The third time I took the ground off the normal ground wire for the relay and the fan and ground them to the frame. I’m getting a lot more air blowing inside. Also I checked the voltage at the relay which is like 11.4 volts which I like but it still burned out the relay. I’m about ready to bypass the relay and just put a toggle switch in. I don’t like doing that but that’s all I can think of to do. Ok I had to go down and buy a new relay to make everything right. Before and after with the motor off it gets 12.5 with it on it gets 14.5 which is the voltage from the alternator. And the fan is on high. Also it is the coil.

 

Is the fan relay failure due to a burned-out coil or pitted points that no longer conduct? The fan relay is only in the circuit when the fan is on the highest speed setting. This is to limit the amount of current going through the control switch. Is the 11.4 volts at the relay with the engine running? Is it also the same as the voltage at the battery? That seems to be very low.

 

Ok I had to go down and buy a new relay to make everything right. Before and after with the motor off it gets 12.5 with it on it gets 14.5 which is the voltage from the alternator. And the fan is on high. Also it is the coil. I took the relay off this time so I could get a better reading

 

What were the conditions when you got 11.4 volts at the relay?

 

The relay was bolted to the car so I was not able to get my volt meter leads on the terminals good enough so I took the relay off and flipped it over. Then I got the 12.5 voltage.

 

I suspect with the good ground, this relay will last. Corvette A/Cs of this era are marginal at best when new. I've seen reports that installing a '84 fan motor (requires a spacer) improves the cooling as it moves more air. Also switching to R134a degrades the performance since it's not as efficient and the system wasn't designed for it.

Might check the rest of the grounds as bad ones can cause all kinds of gremlins, especially in a plastic car.