How do I exactly 'burp' the cooling system? I'm installing a new water pump and hoses on my BRAT tomorrow for the first time. Pointers?

EA81's don't generally require burping. Just fill it, start it with the cap off, and fill a little more, replace the cap and it should be good. You might find it needs a few more ounces after the first cool-down. Don't overfill the radiator as EA81's have no overflow bottle and the system will "seek" it's own level - usually about 1" to 2" below the filler neck. If you fill it past it's desired level it will just spit it out on the ground the next time you get it hot.

 

GD

Thanks GD. You told me that yesterday, but I got to reading threads on here and my mind began to wander... Overthinking it I suppose!

If you want to be absolutely sure, pull your thermostat, after installing the lower hose, and fill the block directly.

After filling the block, put the thermostat back in, re-affix the housing, and finish filling the system via the radiator.

It eliminates the need for any burping and any chance (negating freak occurences) of it air locking.

 

Twitch

You also want to turn the heater temp selector to the hottest setting, this will make certain the Heater core valve is fully open to allow coolant to fill the core too, i think alot of people do forget this and that is how they get air.

fill the block by the upper hose first, then fill the radiator after the hose is tight.

The cooling system is now fully operational. I drained the coolant by removing the lower radiator hose, so I could avoid breaking the little plastic drain plug. Then I disconnected all of the hoses and replaced the clamps with nice, new German ones. I unbolted the thermostat housing and replaced the tiny POS one with a nice, new, BIG Subaru one from the dealer. Photos:

Old crappy one:

 

Nice new one:

 

Notice the difference in size and build quality between those puppies!

Then I replaced the water pump, which was the genesis of this whole thing, because the bearings in the old one were shot. Put everything together and filled the radiator with coolant and fired her up. the BRAT runs great, stays cool, and the heater is warmer. No burping involved. Pretty painless procedure! SUCCESS!

Congrats.

Did you top up the system after the initial warmup?

As long as the level is within 2 inches of the top I wouldn't worry too much, but it may have had to refill the heate core and a pocket or two, so rechecking your level would be a good idea before you really test it.

I did recheck it after a day of driving and heater using. I had to put in about 2 more inches worth of coolant. I'll periodically check the level, but it runs great!