I am having an issue with my 1969 OTS I could use some advice on: after running the car I can hear what sounds like liquid moving on the exhaust side of the engine. I assume it is the cooling system, but not sure.
A bit of background on the car and the cooling system:
the car sat in a garage for 45 years before I acquired it a year ago. I have been going through every system in the car. The engine runs strong with good oil pressure.
cooling system: I have replaced all the hoses, the heater pipes, the heater case and matrix, had the radiator re-cored, and flushed the system several times. The coolant in the system looks good, same color as what I put in and is clear.
Heater matrix gets hot, the thermostat opens and cooling fans go on as engine gets hot.
I am thinking there might be air in the system? I filled the system with the front of the car raised.
Yes, filled with heater valve open, the radiator is full when cold and has a plain cap and the expansion tank I believe the expansion tank has the right pressure cap (it has a a spring with rubber washer at the end which seals the neck of the expansion tank).
Use a mechanics stethoscope (inexpensive ones are available at any auto parts store) and locate the exact source of that noise.
BTW, the coolant level in your expansion tank on the firewall should achieve a consistent level after a few drives of about 3 inches below the mouth of the tank after the engine cools. Any more and it will be expelled through the overflow when the engine heats up.
When you say coolant noises…do you mean boiling coolant? I’ve seen engines where people put in a couple cans of stop leak, this settles in the bottom of the cylinders and can cause the coolant to boil after the car is shut down.
My helpful assistant (lovely wife) h gave me a hand and had a listen. She was able to better identify where the noise is coming from: seems to be the cam cover area near the oil filler. Is it possible the noise is oil going back down to the pa n?
Remember that the oil is @40psi or so when you turn the engine off. So there will be some movement in the oil system until it bleeds down. The original filter canister doesn’t have an anti-drain valve, either. So it’s dripping back into the sump.