ok I changed my timing cover today because the people who built my motor stripped out a bolt hole. at the same time I put the stock balancer pulley and alternator pulley back on. had the 25% underdriven pulley on it. bolted everything back up and now its like I cant get the cooling system to burp all the air out. I put a new thermostat just to see if that was the problem, wasn't it. so I had another water pump that I broke a bolt in. other than that it was working when I took it off. took the bolt out and put that pump on and still the same results. it starts to overheat. I have the cap off to get all the air bubbles out but its not working. never had this problem before so im stumped as to why this is going on. Any help is appreciated.

 

Just leaving the cap off won't Guarantee you get all the air out.

The air has to be forced out. Vacuum and fill the system usually get most of the air out.

You can try closing the cap and letting the system pressurize as it warms up. Every few minutes Crack it open to bleed the pressure off.

 

did that several times. I finally took the new thermostat off and just ran no thermostat and it had no problems besides being really cool. so I exchanged the new one for another one just a little but ago. ran good for a little bit but still started to heat up. I always leave the cap off to help get the air out but its not working this time. how would you go about vacuum filling?

 

I had a monte carlo that would not bleed out after putting heads on it. I ended up having to pull the hose off that comes up from the steam caps/tube until coolant came out. Got lots of air out. Had no problems after that. Just a thought.

 

make sure the truck is cold
fill it up with water/antifreeze
leave the cap off
turn on the truck
loosen one of the heads water lines on one side,
*there the ones that connect from one head to the other.
there's one on the front, under the intake manifold, size 10mm I think
once water starts coming out, tightened it back up.
make sure you have enough water once your done.
and see if it helps.
that's how I do it.

 

Ok I'll try that tomorrow morning. Thanks!

 

I have used a tool similar to this.

It uses shop air to pull a vacuum on the cooling system. Then you shut the air off and flip a valve. It uses the vacuum force to suck coolant from a bucket into the cooling system.

 

I did the steam vent trick from the head and all is good now. Just weird that I've taken these motors apart for the last several years and never had that problem before. Thanks for the knowledge!