Coolant seals or air...Video
 

On start up with the heat on full the coolant just sat there. Once it warmed up, never past 1/4, it did this till the funnel was getting full to the top.


The idle is really high right now ~2200, just switched out the TB and haven't adjusted it yet.

Got a little nervous and shut the car off before it overflowed.
Coolant seals or air?

Thanks as always!

So you ran it without the cap until warm?

That's why it's boiling...

How long are you supposed to run it?

after the thermostat opens, and you see the coolant level drop... start squeezing all of the coolant hoses to get the air out. do this within about 90 seconds of the thermostat opening (pretty easy) and refill coolant again. replace the cap, done.

That makes a bit more sense :)

Shouldn't the air be out of it now though? I never disconnected the funnel from the filler neck.

I only go about a minute at most. If your coolant seals are blown, you'll know right away when the bubbles start coming out on cold start. If you're trying to burp all the air, you can do that with the engine off. Just use the same funnel in the same place, add coolant, slowly squeeze the lower hose. Bubble bubble bubble, add coolant, repeat.

The cooling system is pressurized, and fluids boil at a higher temperature when under pressure. Removing the cap depressurizes the system, allowing you to experience a little localized nucleate boiling in the engine. The tiny bubbles collect, then fly up to the surface all at once, looking like a big glob.

Here's a sure way to find out if your coolant seals are blown:

Block Tester | AutoZone.com

Cool, thanks. It didn't have bubbles coming up on the cold start. Only when I let it boil :)