Yep, my 06S came without a radiator drain plug so I need to remove the lower radiator hose to drain coolant. I have already removed the retaining clip and doused the thing with penetrating spray and silicone lube but it’s not coming off with me tugging on it. Any tips or tricks to this???

 

On my car they were very stuck. I used screwdrivers and prybars to start things moving. I probably tapped it with a hammer and a punch too. The O-ring inside gets stuck to the radiator. Just make sure it comes off straight.

 

Been a while for me, but I recall I ran a right angle pick (or a small flat tip) around the lip and a couple of trim tools while levering the sucker (read: wiggle). Can’t hurt to spray some more silicon in the groove you pulled the clip from. If the pick tip or flat edge is long enough you can go around the circumference to push/pull that o-ring off the radiator outlet. Good luck!

 

FINALLY GOT IT OFF! Unfortunately there is no easy way to get it off other than brute force. get a good grip on what you can, and just start pushing/pulling up/down and back towards the rear of the car. It will eventually pop off. It really wasn't until I said F-it and just went HAM on it, did it finally come off.

Good luck to all those struggling with this.

 

You need even more force to get it back on. And then cunning and skill and pure luck to get the locking clip to latch perfectly. It will hold on just fine for a while of course even if it's not seated just right. Like when You are going for a test drive after fluid replacement and get to about 10 miles from home before everything is warmed up and put your foot to the floor for the first time and then it blows off... As me how I know...

 

Crazy and very messy but I use a pressure tester to pressurize the system. Sometimes that pops it off others it will help with your prying. Be prepared for a big mess.

 

Also, don't lose the bloody clip as they are not sold separately!

 

When I replaced my water pump I sucked the coolant out of the reservoir.
I think I've only intentionally tried to "drain coolant" once in my life. That's what the ground is for. :P