[SubiefanParker]

I'm kind of worried about what this might be.. I look in the overflow or the radiator cap and see a brown layer of stuff in the fluid. Also the level in the overflow is lower then it was a week ago. Its an 03 wrx 2.0 liter with 108k.

 

[SD_GR]

When was the coolant replaced last? Look for a leak, pressure test, and if the coolant is overdue, replace it.

 

[SubiefanParker]

The guy I bought it from said he did it at 100k when he did the timing belt, but he used red or pink and green radiator fluid because he didn't have anything else. I hope that didn't mess with the coolant system.

 

[subaru_crazy]

radiator fluid....green or pink? what gives..? - YotaTech Forums

Read through the post above, but basically who ever changed the fluid should have stuck with either the pink or green, when they mix that is why its going brown. If I were you I'd do a proper flush pronto and replace it with only 1 type of fluid, whether it be the pink or green.

 

[SubiefanParker]

I think I'm going to do that tomorrow. What is the proper way to flush these engines? I'm new to this car.

 

[scoobaru03]

We have BG flush machines at our shop, it cycles the old stuff around then purges it and puts the new coolant in. A regular drain and fill wont get all the fluid out of the system. Just have them do a coolant system flush more than likely they'll know what you mean. If they have the BG flush machines they'll put additives to break up anything in the system and actually does a pretty good job.

 

[teflon_jones]

radiator fluid....green or pink? what gives..? - YotaTech Forums

Read through the post above, but basically who ever changed the fluid should have stuck with either the pink or green, when they mix that is why its going brown. If I were you I'd do a proper flush pronto and replace it with only 1 type of fluid, whether it be the pink or green.

You should be reading the sub-link from the site you linked to because it's the only one with the correct answer:
I drive a Toyota and do all of my own... | Car Talk

As it says, all color indicates is lifespan. 50k miles for green/blue or greenish-blue, and 100k for orange/red which is long lifespan. There is absolutely zero problem with mixing them and anybody that says there is, well, they have no idea what they're talking about. The only reason it's brown is because if you mix orange and green you get brown. Any sediment or any other issues are not caused by the mixing of coolants.

The only thing you shouldn't do with long-life coolant is put it in older cars prior to the early 80s. Those older cars can have certain metals in the cooling system that can react with the newer additives and corrode the system.

 

[SD_GR]

It should I think be noted that Honda and Subaru coolants have a 100K mi lifespan and are both blue.

 

[teflon_jones]

Yes, some manufacturers have bucked the trend as long life coolants became the standard rather than the exception.