Squeaking Sound Coming from 225 /6

chinze57 said
I daily my ‘64 Dart (225 Slant 6) and usually have no issue. The past few weeks i had a low oil pressure light on, but had plenty of oil so I changed my oil a week or so ago.

I should note, after looking through service records, my mechanic most recently put 15W-40 during an oil change, whereas I use the recommended 10W-30, so I had mixed oil weights when topping off after checking fluids previously.

Well after the oil change, light stayed on. I haven’t driven much this week, last time I drove was Sunday. Today when I started my car, the engine didn’t so sound right, slightly bogged down, and when revved (in neutral), squeaked. I revved again and it’s squeaked again. I have enough oil according to the dipstick.

I suspect there’s an issue with the oil pump and the engine is running dry. Any thoughts?

I would put a mechanical gauge on it and find out what the oil pressure really is at idle and at crusing speeds.
From that you can make a determination if there is an oil delivery issue or not.
Typically slant six oil pumps are robust, but the oil pressure bypasss valve should be serviced every 100,000 miles or so.
The squeaking could be an oiling issue, like maybe there is no oil getting to the rockers,,,anything is possible, so put a mechanical oil pressure gauge on it and respond with the oil pressures.
And mixing 15w40 and 10w30 is not the cause of the issue.