Cooling system issue. Please impart your knowledge on me!
My 94 5.7 Caprice had a non-functioning temperature gauge since I bought it. On Christmas day, my waterpump gave up the ghost at some point during a 45 minute drive home.
I replaced the pump and thermostat with new units. Since then I have been unable to bleed the cooling system.
After repeated attempts over 3 days using multiple techniques suggested on this forum, still no joy.
I began to wonder if perhaps I had blown a head gasket. I broke out my cheapo compression gauge. I checked cylinder 1 first. Perfect. Cylinder 3 showed 0 compression. Retested 3x, all 0. Retested cylinder 1 to be sure, tested good. Disgusted, I through the gauge on the bench and quit for the night.
The next morning, I tore into the motor, pulling the heads. I took the heads to a local machine shop to be checked. At first glance, he told me that they looked beautiful and asked me if I was sure the gauge was working properly. Long story short (ok, shorter), it wasn't. Heads advanced head gasket weren't the issue.
Wait nearly 2 weeks for all the parts to come in and reassemble.
SAME ISSUE! Flushed heater core (it was plugged), flushed entire cooling system including pulling the knock sensors. Refilled and spent hours trying to bleed.
No luck. Flushed the whole works again and installed a coolant filter, replaced overflow cap, drilled a 3/32 hole in the thermostat. Still won't bleed!
To recap, heater core inlet hose is cold. All other hoses hot. Air from the bleeder never fully goes away (I am elevating the front end). No heat in cabin. Car won't hold temperature. It goes straight past operating temperature to overheating.