I just replaced the heater control valve and I have air in the water system. What would be the correct way to bleed the air out?

I don't see any bleed valve. It's a 96 B2300.

Thanks,
zoti

 

Just let it run in neutral, with the radiator cap off. Keep an eye on the coolant level. You need to make sure that the thermastat fully opens. When you cannot put your finger into the radiator, because it is very hot, then you will have bleed out the air.

 

Thanks. It's a bit cold and I waited about 15 minutes but the car will not warm up. I guess I will do the same but take it for a ride tomorrow so it will warm up.

 

Don't take it too far...if you have a lot of air in the system, it can quickly overheat once the temp gets up, especially considering the gauge is totally useless for telling actual temps.

Just keep the radiator topped off as it's warmed up and you'll be fine.

 

Fill up the radiator until it won't take any more. I strongly recommend a "spill free funnel".. about $20 from most parts stores.. if you use one, fill the funnel about 1/3 of the way.

Start the engine.. do NOT rev it.. let it idle. Turn full heat on LOW speed on VENT setting. Periodically watch the temp gauge.. if it starts to go above 3/4 shut off the engine and let it cool off a bit (30 min or so) and try again.

It will take much much longer than 15 minutes to warm up on a cold day. Periodically feel the upper radiator hose and the air being blown out by the rad fan. Once these get hot, the thermostat is open. You may experience some antifreeze boiling out JUST BEFORE the thermostat opens.. this is normal, however if it does this more than 30 seconds or so and the thermostat is still not open... SHUT OFF THE ENGINE.

Once the thermostat opens it will suck down a BUNCH more antifreeze, just keep adding until it won't take anymore. The first time the thermostat will not stay open long... let it keep running until it opens again. Add more antifreeze... then install radiator cap and fill the plastic tank about 2/3 of the way full.

ALSO once the thermostat is open, check the heat inside the cab. If it is blowing cold air you still have air trapped.

Another option is to remove the thermostat, and while the housing is disconnected, fill up the cooling system until antifreeze spills out of the thermostat hole.. then install the thermostat. This will purge 99% of the air out of the system. If you choose this method install a new thermostat while you're at it.

Good luck.

 

Thanks. I drove it around and it looks like all the air is out. It won't overheat and everything looks normal. Tempereature, heater, everything works fiine.

 

If you're not overheating and the heat works well, you should be good to go.

Just to make sure.. let it sit overnight and get good and cold.. then remove the radiator cap and make sure it's full.. if not top it off.. put the cap on and you're.. GOOD TO GO

 

Thanks guys.