Air in the cooling system? Educate me (3B) (1 Viewer)

[Reinhardtius]

Hi Folks

I had my radiator patched up (Little weep from my radiator) and the result is holding up great. I also did three flushes with distilled water, and then emptied and refilled with Toyota pink 50/50 coolant.

My refilling procedure involved a funnel attached to the radiator cap (see here: Red Land Cruiser (@redlandcruiser) • Instagram photos and videos), and parking on a slope, so that the radiator cap and funnel were higher than the radiator. It took such a long time for the funnel to not have any bubbles popping up every once in awhile. I squeezed the radiator hoses, moderated the idle, and just let it sit. After an hour and a half, I said enough was enough. I put the rad cap back on, filled the overflow tank, and started driving it. It has driven great, per usual.

The peculiarity I have is that, on three occasions after parking it from a 10-20 min drive, I get some drip drips from the coolant overflow outlet hose onto the ground. It's not gushing out, but it is maybe 1 cup of coolant that ends up on the ground. I see no unusually hot temperatures or anything. The temperature gauge stays at about the 40% mark.

Questions:
1. Have I just overfilled the cooling system, or do I have bubbles still lurking in there?
2. Are there any bleeder valves on a 3B? I did not see anything mentioned in the maintenance booklet.
3. How do you bleed your 3B?

My assumption is that over time, any air bubbles will get pushed into the overflow tank, and out into the atmosphere through that coolant overflow outlet hose. Should I take off the radiator cap after the engine cools after having driven a long drive, to let air out?

Your advice much appreciated,

R

 

[RufusTheDufus]

It's not a good idea to remove the radiator cap to let air out, even after the engine cools completely. That is likely to introduce air into the cooling system. A recovery type of radiator cap will pull coolant from the overflow tank as the engine cools. If you break that siphon from the overflow the hose fills with air. It's not a lot of air but if you're chasing small bubbles, pulling the cap like that is potentially a source of small bubbles.

Does a 70 series have a heater control valve mounted on the firewall like the 40 series? These valves are a great place to bleed air from the system when parked on a flat surface. The hose connections to the valve are often at the highest point in the cooling system. I installed one of those cooling system flush kit 'T' fittings inline near the heater control valve in my BJ42 and BJ45. They are the highest point in the system and makes it easy/convenient to make sure there's no air.

If you're trying to get air out the cooling system don't forget to adjust your heater to the hottest setting to allow water to flow through the heater core and displace any trapped air. A small amount of trapped air when the engine is cold will be a somewhat larger volume at normal operating temperatures.


Edited to add: your cooling system is likely a little overfilled. How much coolant is remaining in the overflow when the engine is cooled completely to ambient? Your post said you "filled the overflow". Does that mean you filled it to the cold line or you filled it to the top?

 

[SHREDwagon]

This is what I use with BOTH heaters set to hot: