Radiator drain spigot: Very difficult

The repair manual instructions do specify that the cap is on, so the system can come to normal temperature and pressure. I don't pretend to be an expert on why, but it could make sense that at operating pressure, the same amount of trapped air occupies bubbles of smaller volume, and may be carried more easily through the burp hoses back to the bottle.

I usually have my ScanGauge connected, so I can see the coolant temperature; it gives me something to watch while I am sitting there thinking "are we there yet?". In cooler weather, it might seem to plateau somewhere shy of the 95 ℃ trigger point for the fans. If I see that, I'm not completely above pushing the go pedal slightly to help the process along.

 

I had the same problem - was scared I'd break it. Ended up finally getting it unstuck by grabbing it with a pair of needle-nose pliers and twisting very hard. I also soaked it in a lot of WD-40, not sure if that helped or hurt.

 

Yes that is what it looks like. I followed the nuts about bolts video for my coolant drain and refill and it went textbook perfect the first time.

 

As the stopcock is plastic and not subject to rust, I don't think WD-40 does much for it. I would be a little concerned about WD-40 having some possible chemical incompatibility with it, embrittling it or something.

 

Silicone spray maybe?

 

This sounds like the same kind of thing that happens with the oil filter cap.This stopcock seals with an O ring. There's no need to even have it tight at all, beyond turned all the way in. I found it awkward to open by hand, just because my hand doesn't bend that way, not because it needed much force to open.

Unless the last person who tightened it thought it had to be übertorqued for some reason.

 

Isn't there just a lower radiator hose we can disconnect to drain the coolant?

I watched a mechanic's YouTube channel yesterday, and he said he never uses the radiator stopcock. He always disconnects the hose because on older vehicles, the stopcocks get fragile and break. For me, I never had a problem with the stopcock, but if you have difficulty with it, perhaps it's less trouble to simply disconnect the lower radiator hose.