Recently had the original A/C system in my 1970 Series II FHC re-charged with R12. Cooled fine for awhile, then began to lose it’s cooling efficiency. Driving the car on a warm day (80+ farenheit) with A/C on (it was not blowing cold air) and the oil pressure gauge shot clear past 60 and out of site. I turned off the A/C and the pressure slowly returned to normal. Turned on the A/C and the same thing happened again. The belt did not squeal and the engine seemed to run fine. Changed the oil and filter. Drove the car numerous times without the A/C on and engine oil pressure was normal. What could be the connection between the A/C and the engine oil pressure?
I don’t know exactly but I’ll bet it involves electrical connections and not an actual oil pressure issue.
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Baffles me too… but it almost certainly has to be electric. Almost as though something is wired incorrectly I have factory A/C and can’t imagine what it could be.
LLoyd
Wherever space and time interact, there is information, and wherever information can be ordered into knowledge, and knowledge can be applied, there is intelligence.
Pavel Mirsky, mid 21st Century Russian General
When I had a 74 Ford I had a a problem where the radio static would gradually go up, accompanied by the temperature gauge going until it was pinned. No overheating. Suddenly the static would disappear the the temp would drop to normal. Then the cycle would repeat. I looked everywhere and for every possible cause and finally found the problem. What I should have checked in the first place was the engine to body ground strap; it was loose. I cleaned the area tightened the bolts and all was well.
I’m not saying that’s your problem, I’m just pointing out that electrical gremlins can cause really odd symptoms. Even on simple, pre-electronic everything cars.
The oil gauge goes to 60 plus pounds when the lead to the sensor on the filter block is grounded out somewhere en route. Might start there.