So I was at a gas station all they had was green coolant mixed 50/50 but the car had yellow coolant. The level in the reservoir was just under the minimum level and proceeded to top off the coolant which mind you I thought this was yellow coolant I was adding to the reservoir but was green thinking I just ruined the cooling system only a little over a quart was added. Is this okay until my next service to flush out and exchange which will be about the next 2 months?
Why not have the service done now and not wait two months?
what does your bottle of Green Coolant say it is? if it happens to be a universal coolant, then you are likely ok. If not, then you should have this flushed as soon as possible.
*Edited to remove my misspeak about yellow coolant not being ethelyne glycol, cause it likely is. 
All coolants are ethylene glycol.
Only Sierra is a propylene glycol
Which means you can drink it, and it won’t kill you.
Tester
All?
Is Dexcool ethylene glycol?
Granted, this Ford likely doesn’t have DexCool in it, but not all coolants are the same.
It’s the additive packages in the ethylene glycol that makes the differences in coolants.
Tester
1 Like
Most of the yellow I have seen is Prestone Universal which they claim can be mixed with anything. The Prestone is supposed to be a 5 year coolant but the green I have seen is only a 2 year coolant.
My car has the pink Toyota extra long life which is supposed to have a 10 year life from thefactory but onlt 5 years after the first change. It is only made as a 50-50 mix.
I wonder what you do if you live where it is really, really cold.
After work yesterday I finally had the chance to read the bottle it is not universal fluid and it does not does not state that it can be mixed. Is even a quart of the wrong fluid going to do excessive damage? However I fear that I’ll end up doing damage to the car before can get the flush and change can be done which I plan to do in the next few days hopefully.
It will be fine…I wouldn’t want a large portion in the system, but that little amount won’t hurt…especially in the short term.