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
 
 
 

Reddtarga

Hoonsy
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?

For topping up a different mix shouldn't matter much.
If you are worried about it why not ask your mechanic what mix and brand he used. 

Considering it was a year ago, I doubt he'd remember. Could be worth a shot however..
If I intend on picking up the red coolant, is there a recommended brand/mix that everyone here uses?

Toyota 50/50

That's why I'm confused. Toyota recommends their red mix, but doesn't it all come down to Japan having a law against silicates in coolant?
 
Edit: apparently Japan also has silicate free green so that may not mean anything then

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

Getting concentrate is a really good tip if it's true the older engines don't have a drain plug on the engine, that way you can flush it with water, then calculate how much water is still stuck in there and add the concentrate.

Hi Hoonsy,
Yes you do just go to your Toyota Dealer Spares Dept & ask for red coolant.

 
+1
Also tell them what car you have.
But make sure you get the 'Toyota Red concentrate' that comes in 4 liter containers (that will make up 8 liters of mix).
 
Don't get the 'Toyota pink long life pre-mixed', as I mentioned previously.
 
How many containers you need will depend on whether you only want it for top ups, or whether you want to do a full coolant change.
 
 
 
 

Don't wanna drain all the coolant completely, feel like I'll do something wrong. So just a top up/bleed air out will do me haha

Thanks for the help fellas. Fingers crossed I do it without any drama :)

Reddtarga
 
Five year change intervals??
My owner's handbook says one year or 20k
 

That's what it says on the (aftermarket product) bottle.  I'm fine with that, as I figure the chemistry has come a long way since my MR2 was built.  I used to use some weird red Toyota corrosion inhibitor additive (closer to when the car was new), which came in 250ml bottles and is long since discontinued, and even that was to be replaced every two years.