I have an annoying air pocket that for the life of me CANNOT get rid of. Pressure tested, exhaust gas tested, everything that coolant flows through that isn't the engine itself or the heater core is new. Anyway, I'm wondering, can air naturally bleed out on its own through the expansion tank or is literally the only way to get rid of this air pocket to get it out through the bleed screw? Assume that the entire system is buttoned up and sealed and there aren't any leaks.

 

@Brandon318 It is brutal get rid of air in the system, you can try jacking the front end up that can help. But there is no simple way and in general you only get air in if you have coolant leaving.

 

In my opinion, bleeding the coolant of air is a simple process discussed on here many times. It is far easier if you have the inline thermo mod.

With that said, I had the exact thing happen to me on one of my discos a couple years ago. I would bleed and everything was good for a few days then I would slowly start to get the waterfall sound back. I never overheated and just occasionally had to top off my coolant. It went on like this for about a year and I pressure tested and all that trying to find to source of the leak.

I found a beautiful truck with a bad motor so I yanked the motor out of the truck in question to swap out and found the problem. A pinhole size head gasket leak at the rear of #7. A black spot about the size of a silver dollar was on the rear of the block where it meets the head. I was surprised that it never gave way to a big problem.

You might get a little inspection mirror and check at the rear of the block up against the firewall. Good luck.

 

NEED to do this while the engine/coolant is cold.

1 - Park the truck on an incline with the front facing up (or jack the front up).
2 - Remove the bleed screw.
3 - Fill the expansion tank.
4 - Here's where it gets a little strange (and why you need to make sure everything is cold)... Put your mouth in the expansion tank hole (need to create a seal with your face) and blow. Make sure the tank is full and that you are not introducing more air if the coolant level goes all the way down.
5 - Keep blowing until coolant shoots out of the bleed screw hole.
6 - Install the bleed screw as you continue to blow.
7 - Top off expansion tank if necessary.

Works every time.

 

Why not lift the expansion tank instead of pressurizing it?

I open the bleed screw
Lift the expansion tank up
Close bleed screw
Put the tank back

 

I think this can be done with a coolant pressure tester too.

 

I feel like bleeding cooling systems has become witchcraft to this forum...

If you have no leaks, and everything is working right, all you need to do is fill the reservoir, leave the cap off, and run it for a bit. Run it and then crack the bleeder. You don't need to remove the bleeder. Once you get a solid stream coming out of it with no bubbles, you're done. Top off as needed in the bottle and drive away...

Do you think you will ever see a mechanic shop lifting the front of the car, then the back, then blowing in the reservoir, the dancing in a circle and saying a prayer? it isn't rocket science...

 

Have you flushed the heater core?

 

When I have it on an incline I squeeze my hoses which makes coolant flow back and forth and dislodges the air.

 

I have indeed. With how crusty the inside of my radiator was (I cut it open), I wonder if the heater core is plugged up and there's a pocket that just can't exit. Options are...

1. Replace the heater core.
2. Flush it with vinegar for a few days to see if mineral deposits might dislodge or dissolve.
3. Carry on and just hope someday it all works itself out.