White sediments at bottom of coolant reservoir

[ljeffyoung]

What is this?

 

[stickerbush]

Looks like remains of coolant that spilled when reservoir was filled.

 

[Silly Wabbit]

Looks like remains of coolant that spilled when reservoir was filled.

I think op is not asking about the outside crust but a layer of sediment inside the bottom of the tank.

 

[Jmaz]

Looks like it's on the outside. Could be mineral deposits from hard water or road salt. Has the OP tried wiping it off.

 

[ljeffyoung]

Looks like it's on the outside. Could be mineral deposits from hard water or road salt. Has the OP tried wiping it off.

Not outside, inside. I vacuumed 16oz out, there was some white salt like sediments in the coolant. Maybe caused by mixing coolant? Jiffy Lube add some so called universal coolant to my reservoir without asking me (been ripped off) then I replaced the whole coolant in Mazda dealer.

 

[wlong01]

Not outside, inside. I vacuumed 16oz out, there was some white salt like sediments in the coolant. Maybe caused by mixing coolant? Jiffy Lube add some so called universal coolant to my reservoir without asking me (been ripped off) then I replaced the whole coolant in Mazda dealer.

Probably minerals from the water they added. Do you have hard water in your area?
Stay away from the corner quick change oil places. If you can't do it yourself take it to the dealer or a trusted auto repair place.