69 442 convertible, matching numbers, full restore.
On the way back from Crusin the Coast, notice AC cycling a lot and my normal operating temp of 190-200 deg, climbed to 210 deg. (Cruising on interstate at 70 mph. Weather was 84 deg and sunny.) I stopped at a rest stop and noticed a bit of oil, which seemed to be from the front of the compressor, clutch area, sprayed on the hood insulation. I was told that this is normal for this type of compressor. I do not believe that the AC is functioning normal.
1. Is it normal for the temp to run at 210 deg, with the AC on and the weather condition mentioned above?
2. What about the AC cycling and spitting a bit of oil???

System is charged with R12.

 

1 - That temp does not sound out of the ordinary to me, but "normal" for your vehicle may depend upon the engine RPM at the speed you were driving. On the highway at 70 MPH (~3400 RPM) in my car with the AC on in the summer 110+ temps, the coolant temp would go up to 220; slowing down to 3000 RPM or below and the temp would run ~200.

2 - AC cycling rapidly is a typical sign of low refrigerant. You should be able to look at the sight glass on the drier and see if there are bubbles. If so, this says low refrigerant level.

I have read here on the forums that a slight amount of oil seeping from the front seal area is typical of how the compressor is made, but I have no first hand knowledge of the accuracy of this info.

 

Good thing we know this! Nothing like making an A/C problem easier to diagnose than knowing that the engine, transmission, and rear axle are original to the car.

By the way, what's the car's color? Knowing that would make it even easier to figure out what's wrong.

 

Bigger question is why didn't you have the top down and AC off if 84 and sunny in NOLA?

Temp is not alarming but keep an eye on it, with and without AC running. The fact that it is creeping up might be a warning sign, maybe a slightly clogged radiator since airflow is not an issue at that speed. Was the coolant level OK? Should be about 1.5" below neck if stock without a recovery tank.

 

Thanks guys for the responses. I knew someone would talk about the top being down as apposed to up and running the AC. Actually, 4 days of top down, partying and sun in Mississippi for Crusin the Coast was the reason for top up, AC on, for the ride home. Having said that, I rarely use the AC. Everything on the car is original. I just replaced the water pump, high flow, HD, GMB, for cars with AC. Radiator was dipped and cleaned. I used Prestone premix and have a recovery tank. The car runs cooler, stopped in heavy traffic, than cruising on the Interstate. 70 mph turning approx 3200 rpm. One thing that I did not mention is that I have not installed the radiator splash shields/flaps yet.

 

Fun71, you mentioned running AC while cruising at 70 mphs and 110 outside temp,, does your AC compressor cycle or remain engaged??? Sounds like a silly question, but, I rarely use the AC.... I would think, if functioning normal, the compressor should remain engaged.

 

Be careful here. Even a properly functioning A/C system will see the compressor cycle on and off. If it cycles too rapidly, that is an indication of too little refrigerant. But the compressor should not simply stay on all the time.

Also, how often the compressor cycles depends on the ambient temperature. It will cycle less often on a hot day (95 degrees) than it does on a cooler day (75 degrees) because it stays on long enough for the evaporator coils to just reach freezing temperature, and then it shuts off. It takes less time for the coils to reach this temperature on a cool day than it does on a hot one, so it will cycle more in cooler weather.


Also remember that the compressor can be engaged even in the winter time if you use the defroster, and because it's so cold already, it takes no time at all for the coils to reach freezing, so it will cycle more rapidly in winter than in summer.

If you have any doubts, have the system pressure checked. It takes an A/C shop only a few minutes to connect the gauges, and then you'll remove any doubt in your mind.

 

One word: humidity.

I grew up in south Louisiana and lived on the Gulf Coast for nearly 40 years before moving to Phoenix and I'll tell you top up and AC on was a way of life due to the high humidity. Even mid-80s is tough when the humidity is 70% or above.

 

The compressor in a '69 doesn't cycle. It has no pressure switches of any kind.
Even if you completely run out of Freon, it won't cycle off.

Its output is regulated by a POA valve, which reduces or increases the flow of refrigerant without cycling the compressor.

- Eric

 

I get the smart a comments but i agree, is it the factory ac system? if so seepage from the front compressor seal is common.Also md is correct cycling is not an issue with the poa system.

 

Looks like a trip to the A/C shop. It is the factory system, with POA valve and the compressor cycles.