Sludge in Radiator Overflow
 

Found sludge in radiator overflow.. what do i do??

Use it as a sundae topping?

What color is it? Google searching hints at possible oil contamination.

What coolant do you use? Is it possible that the factory FL22 (is "FL22" on your radiator cap?) might congeal when mixed with other coolant brands?

How old is the car? Mileage?

When was the last time the coolant was changed?

Where are you from?

When did you notice this happen?

Were Venus and Jupiter aligned with the Sun?

62,000 miles on car. FL22 coolant. I was checking the fluids and found sludge in the radiator overflow, so I got a coolant flush and fill. Mechanic said it was coming out clean, but I am still seeing chocolate colored sludge in the overflow tank.

chocolate color? engine oil?

you will always see some sludge/crap in your coolant overflow tank.

remember when your car heats up, coolant expands and will push some air out of the system,

but when it cools down, the coolant shrinks and will create a vacuum and "suck" some air with dirt/dust back in.

so a little bit of "crap" is ok, but if u see a lot, then you might want to make sure you're not having an leak.

keep an eye on the dip stick for water in oil.

Since it was just flushed you will get residue floating around for awhile.

Update... Blown engine! I've taken very good care of this car. Always checking oil level, using proper octane fuel, changing oil every 3,000-4,000 miles and now this. Mazda will cover the engine but not the parts destroyed by the blown engine (hoses, radiator etc.) WTF! Gonna fight'em on that one. Gonna get this car paid off and then trade it in. Found out about a recall for this exact problem. I never got the recall card. Should I get a Ford?!?