Upper radiator hose getting pressure when cold?

[454cid]

The radiator is in communication with the block via the bottom hose so the pump sees an open path (assuming a clear radiator - which appears to be the case).

True, I didn't think of the lower hose.... outa site sotta mind, I guess.

As mentioned earlier, pressure is from heat - or gasses escaping the engine.

I understand, but I'm talking about a cold engine.

 

[Pinger]

I understand, but I'm talking about a cold engine.

In that case, if it's a leaking head gasket, the coolant should have a smell of gasoline what with the mixture being so rich on cold start.

 

[454cid]

I put the pressure tester on it today, and I had to let it run a couple of minutes before the needle started moving, and when I removed it, the coolant was warming. I still may do the chemical test, just to verify further that I'm fussing over nothing.

 

[someotherguy]

If there's no trail of bubbles going to the reservoir when the engine is fully warmed up and running, I wouldn't sweat it. Slow warm-up probably is a bad thermostat, stuck open.

Richard