Hey, just bought a '03 Dodge Ram 1500 4.7L and am in the process of fixing a few things.

I recently replaced the thermostat, and filled the system back up with coolant, although I left most of the overflow reservoir empty. I started it up and let it run for a bit, and according to the gauge, the engine got up to normal temperature (needle was right in the middle). However, the coolant level rose until it was bubbling out of the reservoir. I was under the impression that the coolant level would drop as air pockets were purged out of the system. Any thoughts/advice would be appreciated. Thanks.

 

The coolant will expand as it warms, as will any air trapped in the system. Usually, ya just let the thermostat cycle a couple times, and you are good to go.

 

Did you fill past the max point for the overflow tank? The coolant doesn't really reduce due to air bubbles as it's heating. It expands and burps but keeps expanding.

 

Silly question, but did you move the heat control to hot?

 

Yeah, I have the heat control set to hot. The hoses going to and from the radiator get hot once the engine heats up, so I assume the thermostat is working correctly, although I can't get any hot air to blow out. Right now when I start it up, the coolant reservoir only has a bit of coolant in the bottom of it, but once the engine gets heated up, it's bubbling out of the top of the reservoir, with the engine gauge showing its overheating within another few minutes. I'm not sure if I've managed to get a whole lot of air in the system or what.

I haven't been able to get the bleeder valve opened up, but I may try again to get that opened up and see if I can bleed air out through there.

 

There is still air in the system. Air expands a LOT more when it heats, than the coolant does.

 

Raise the front end higher than the rear, or park facing uphill, then run the engine with the radiator cap off to burp it.

 

...or drive it up on a pair of ramps.

 

Thank you all for the help, much appreciated