Getting air out of cooling system after refill ??

[Blakers]

I replaced my water pump today and had to drain my cooling system down about 3 gallons. Once I got everything buttoned up, I could not get all the coolant back in, so I figured it had air in the system (as typical with most vehicles).



I filled it to the top of the radiator, as well as to the full line on the overflow bottle. Then I started it and let it idle for most of an hour, but the thermostat never opened and the top hose never got warm. After idling for some time, I took it for a short ride up and down the road, but still no heat at the top hose. Then I went a little further (probably a mile and a half) and then the temp gauge started to climb rapidly and almost got to the red line. I got it back home at just above idle and checked and the top hose was still not hot.



Any ideas? I will check later tonight and see if it sucked the overflow bottle into the system. I hope it didn't hurt anything by getting that hot, but I barely had any load on it. Thanks.

 

[Blakers]

I went back out after a couple hours tonight and the overflow bottle was sucked down a few inches, and all the pressure was off the radiator. I put a gallon of antifreeze and a gallon of water in the radiator. I guess I'll know tomorrow whether everything is ok or not.

 

[Prairie Dog]

Thats all you have to do. Our eng's don't have the PIA troubles with air pockets like some cars do. I would check it the next couple of times you drive it and after that you'll be fine.

 

[SierraRam]

Turn on you heater it will help get the air out of the system.

 

[rscurtis]

IIRC, the heater circulates water all the time, as the return is used to cool the transmission. Temperature is moderated by changing the air flow over the heater core.

 

[steved]

Did you install a OE or Cummins thermostat... almost sounds like the thermostat is lacking the air-bleed hole??

 

[Blakers]

Thanks for the help guys! Everything seems ok now. As it cooled, it sucked some of the overflow bottle back in, then I topped the radiator off. I drove it all day today and the temp never went over half way up the gauge - stayed pretty steady. Tonight, after it cooled off, I checked it and it was down about 2" in the radiator and the overflow was down about 1/4 of the way. I topped off the radiator again with antifreeze and left it at that. It looks like everything is fine.



(Steved: I don't know about the thermostat as I never took it out)

 

[BHanna]

Mine acted the exact same way. Carry a gallon of pre-mixed anti-freeze with you for a while just in case but you should be good now.

 

[Tinman]

I had this problem a couple of times. Pegged the temp gauge once b/o it. I now fill by pouring into the thermostat hole in the block. Haven't had any issue with this technique.

 

[Blakers]

It seems like it takes several cycles of running the engine and letting it cool to get all the air out of the radiator. Each morning it's been down a little bit, but less each day.

 

[JHofmann]

I just did my water pump too, I removed the t-stat and filled the block and rad thru the t-stat hole. No big air pockets that way, went and drove it and temp gauge was normal the whole time.