I flushed out the heater core and got a bunch of stuff out.. no heat to heat! Nice.. but it cools down at idle and if figured I had air in the system. Now my heater core line w/ the bleeder is pretty corroded and started to crack and a piece broke off at the end when trying to put the hose on for the flush. It doesn't leak once I put hose all the way back on w/ clamp.
I tried to lift up the coolant reserve and got some air out and did this for aprox 20-25 min w/ engine running.
After reading through a bunch of threads on the heater core flush I don't see anything saying when trying to bleed system do you keep cap on reserve tank or keep it off? When you try to use bleeder hole to you keep the cap on or off?
If I can't use the bleeder hole what else should I do to bleed? Is the reserve enough to get air to bubble out if it is raised high enough w/ cap off?
Thanks.
Michael
I bled out mine with the overflow tank cap on, but left it bolted to the anchor points. I did also try bringing the overflow tank up above the heater core, but had better results getting air out of the core with it still bolted down. I have seen a few people that create a "cone" out of a piece of rolled up plastic to put in the top of the overflow tank, essentially making it the high point in the system. I tried that method as well, but had no luck getting the air out of the heater core.
If the heater core connection is already broken / fragile, I would be very cautious about using the bleeder hole on the hose. If the heater core connection at the firewall breaks, it will require something either gets rigged up to make it work, or replacing the actual heater core.
There are several companies that make a vacuum fill system that are reasonably inexpensive. Fortunately I was able to bleed all the air from mine after 10+ attempts, but if I had to do it again, I would look into the vacuum fill system and save myself the headache.
Ultimately you are trying to get the system to build pressure and push the air to the high point, unfortunately the high point is the heater core so it is very easy for air to get trapped in there. In theory, bringing the overflow tank up higher than the heater core should create the new high point, however my car just would not let the air out of the core regardless of where the overflow tank was positioned.