I use a dedicated spill-proof funnel (can be bought cheap from ebay/amazon), but stuffing a funnel extension into another funnel is a great idea too. Make sure the heater is set to the highest temperature (32c) BEFORE draining the old coolant, and ensure its still set to that before filling the coolant loop again. Also ensure your radiator fans are plugged in and working.
Definitely worth putting the front of the car up as high as possible on jack stands. I also removed the coolant pipe from the top of the throttle body. Aside from the top of the funnel this is the highest part of the loop, and is connected directly to the lines that feed the heater core. This will help get the air out of the heater core.
Make sure you fill the system really really slowly! And I'm not talking about pretend slowly. Like glacial slowly. Aim to try and get about 1l per minute or less. Try and spend at least 6-8 minutes filling the system. This will give the trapped air a chance to get out. Make sure you don't let the coolant completely cover the hole in the bottom of the funnel- you should be pouring slowly enough that the funnel never actually fills, leaving a gap past the flowing coolant to give the least possible restriction for the air to escape.
Fill very slowly until coolant starts to spill out of the upper throttle body coolant pipe (after about 5l is added). Connect the upper pipe and its hose clamp, then slowly continue to fill the coolant until the funnel is about 1/2 full- this will give a bit of pressure to help force out bubbles in the next step.
With the car still on jack stands, make sure the car is in neutral, and start the engine. Let it run for a few seconds (less than 5), then shut it off. This will spin the water pump to help get any bubbles stuck in it and behind the thermostat. Don't let the engine run for too long though as this will force bubbles into the rest of the loop. You just want to dislodge them from the water pump and thermostat area. After turning the engine off squeeze the lower radiator and upper hoses to help get those dislodged bubbles out.
Do this a few times until you don't get any larger bubbles out when squeezing the bottom hose. Leave at least 30 seconds to 1 minute between doing this, both to ensure you don't melt your starter and to give the newly freed bubbles time to get out, rather than forcing them through the system when you start the car. For me this took about 3-4 turn on, wait 5 seconds, turn off, squeeze hose cycles.
After you're satisfied that you aren't going to get any more large bubbles out (and that your starter isn't going to melt
), start the car and let it warm up. Every now and then give the upper and lower radiator hoses a few squeezes to help move any smaller bubbles that may be trapped. Keep a tab on your coolant temperatures- ideally use torque or BTSSM to get an actual temperature readout rather than just relying on the temperature gauge. It will probably take a while to warm up- mine normally takes at least 15-20 minutes. Have the fan on and temperature set to max, but ensure the fan speed is set to its minimum value. The thermostat should begin to open around the 82c mark (assuming stock thermostat, you should start to feel the bottom of the radiator and the lower hose get hot somewhere above 82c), and the coolant fans should come on at 95c. Wait until the fans come on and the temperature drops to their turn-off temp at 90c, and then you are done! Make sure you add a bit of extra coolant into the overflow bottle to make up for any tiny bubbles that may be still trapped- these will come out continually over possibly multiple days of driving
.Doing everything above should lead to a near-perfect bleed every time, but if you see your temperature gauge start to move (happens at 104c) turn off the engine straight away and let it cool down a bit. You probably have a bubble still trapped behind the thermostat. Letting everything sit for 10-15 minutes allows some of the heat to soak into the thermostat, opening it and freeing any trapped bubbles. After 15 minutes start the car again and make sure the fans come on and the lower hose gets hot. If the temperature gauge moves again, turn off and let sit for at least 30 minutes to cool down and allow heat to soak into the thermostat. Then you should be golden!
Finally, drain the funnel and put on the radiator cap- being careful with the coolant in the funnel as it will be very hot. I have done this method 4 times now, and each time it has lead to heat from the heater core and a hot lower hose first time, every time! It is time consuming and it does sound complicated, but these engines are very picky to your coolant bleeding method, and an incorrect bleed can lead to bubbles stopping coolant from flowing correctly through the whole loop! This is the quickest way to blow your HeAdGaSkEt
Sorry for the long post- but wanted to get this down in writing
A picture of the radiator I am hoping to be actually enough for this car on track to hopefully make this block of text worth reading 
