Originally Posted by gs1949
I remember reading something many years ago; I can't remember where for sure though, but I think it was probably in a motor's truck repair manual from the early 60s that I used to have. I've never tried this and I am not sure it's a good idea.
Anyway, what the author of this article recommended to alleviate airlocks in heaters is rather simple. He removed the hose clamp from the heater outlet, slipped the hose partially off the fitting, and then drilled a small hole through ONE SIDE ONLY of the hose fitting on the heater. He then started the vehicle and waited for coolant to start squirting out the hole he had drilled. When it squirted out did he slipped the hose into position and tightened the clamp. No more airlock
Like I say, I am not sure this is a good idea in the long term. I wonder if that hole could be the start of a crack in the fitting. But I put it out here now looking for comments.
I like the idea -- but instead of drilling the hole in the metal fitting -- drill it in the rubber (facing up) hose near enough to the end of the hose that when you slide the hose into place the hole is after the clamp.
Remember too, that the coolant won't be circulating through the heater core until your thermostat opens.
You can check for flow patterns using an IR thermometer (cheap one from HF does fine) to see if coolant is moving as expected in a system.