Replacing Thermo/Bleeding the Coolant help

Hey everyone,
 
As we all know I struggle with everything. Hoping to replace my thermostat+gasket in the next few days.
I'm going to be following this guide for the thermostat (which looks easy enough): Thermostat Guide
I'm also considering replacing this sensor while I'm at it
 
I'm a bit unsure of how to go about bleeding the coolant system (as I assume I have to after replacing the thermostat/sensor). I've read a few guides online and here's what I've got from it, hopefully someone can help me out to make sure I end up doing it right:

- Make sure car is level. Grab the two hoses tied to firewall and put on the radiator bleeder, one on the heater core
- Hang both hoses up (ideally on the "frunk" latch) so they're above the filler neck
- Have heater slider thingy all the way to full heat
- Open both bleeder valves?
- Take off filler cap in engine bay, fill with some coolant 
- Close radiator cap (do I close the bleeders now as well?)
- Run engine at roughly 2500-ish RPM for a few minutes
- Open radiator cap again once it cools down, add more coolant mix
- Not sure from there

How can I tell when all the air is out? Sorry if this seems trivial to most of you, just don't want to cause any major damage haha. Oh and which coolant do I use? I was given some when I bought the car, pre-mixed green stuff.. not sure if it's what I need however; do certain cars need certain concentrates/water-to-coolant ratios, etc?

Hi Hoonsy,
Have a look in the Tech Info/How to section of this Forum.
There is an excellent article titled SW20 Cooling System Maintenance, written by Redtarga.
Provides all of the info & instructions needed.

 
Don't mix green coolant with red or you could end up with sludge.
 
If you want to change from one type to the other make sure you do a thorough flush first. 



 
 

Had a look and my mechanic used a red coolant. Is it safe to assume he used a 50/50 mix as well? Or in other words, if I use a 50/50 mix to top it up, will it have any negative consequences if his mix was slightly different?

If I remember correctly, red isn't safe with brass or copper components (e.g. some radiator tanks for instance).  I ended up selecting green coolant as it works with everything, although at the expense of a slightly more frequent replacement schedule (5 years instead of 6).

Flighter
If I remember correctly, red isn't safe with brass or copper components (e.g. some radiator tanks for instance).  I ended up selecting green coolant as it works with everything, although at the expense of a slightly more frequent replacement schedule (5 years instead of 6).

 
FWIW, here's what my Toyota dealer told me:
Toyota Red is fine for your early MR2 with copper/soldered radiators/pipes, and has a better formulation than the green stuff.
 
But don't get it mixed up with the Toyota Pink pre-mix that is designed for aluminum radiators that are used in later models.
Toyota Pink has a completely different organic acid in it than in Toyota Red.
The organic acid in Toyota Pink will damage brass/copper/solder heater cores in 1995 and earlier Toyotas.
 
Five year change intervals??
My owner's handbook says one year or 20k
 
 
 

Toyota 50/50

Aight, so I'll pick up some Toyota concentrate soon then. Do you just purchase it from the dealerships? And if so, do I literally ask for "Toyota red coolant"? Never done this before