Crud in expansion tanks?

[03mineralg]

What is the crud/film that clings to the walls of the radiator/ intercooler tanks? I noticed this a while ago in another members coolant tank when it looked like a piece of something was floating in it. We looked inside and noticed the whole tank was coated with a film that could be scratched off, mine looks the same. Must be common to be in both cars.

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[03mineralg]

CORRECTION, just the radiator coolant tank, not the intercooler, that one is clear.

 

[ShelbyGuy]

stop leak

same stuff that turns the yellow antifreeze brown

 

[03mineralg]

I dont know exactly what you mean? Are you asking if i put in stop leak? Nothing was added to the fluid. 10,000 miles factory fluid.

 

[ShelbyGuy]

the factory put the stop leak in when the car was built. hence the browner color.

 

[03mineralg]

the factory put the stop leak in when the car was built. hence the browner color.

Gotcha, i didnt know that. So as bad as that looks its o.k.? No need to change it? Thanks.

 

[02RedL]

the factory put the stop leak in when the car was built. hence the browner color.

Thats good to know, I was wonderin why it was like that.