Rust in coolant

use the magnet on the powder to see if the particles are magnetic. if they are, it's definitely rust and you need to consider what could be the cause. if it's a static source like a freeze plug, it's unusual to have particles float about the system. the only non-static thing i can think of is the coolant pump impeller or the pump bearing, in which case you need to deal with it asap before it jams and breaks your timing belt.

possibly, but generally they're caustic soda - not good news for aluminum blocks. if you use one, make sure it's the type that comes with a follow-up neutralizer, and follow instructions.

a bad pump bearing could be leaking coolant as well as introducing rust. suggest further investigation asap.

snipped-for-privacy@gmail.com wrote in news: snipped-for-privacy@m73g2000cwd.googlegroups.com:

In addition to what jim beam says, there is also the possibility it's old silica. Silica from cheap silicated coolant can precipitate out, especially if it's very old, or has been used at a too-high concentration.

This would explain your inability to flush it out. It's probably sifted down to the bottom of the water jacket and has piled up there, as well asd in the bottom of the rad.

The best way to flush the block is to remove the block drain and close the rad drain. Now stick a garden hose in the rad filler neck, and feed a high volume of water through it until the water runs clear out the block drain. You can do the same thing with the rad, but you'll need to disconnect the lower rad hose so the water can exit quickly.

There is an additional, more ominous possibility: it's old Bars Leak. A previous owner may have had a leak somewhere, and filled the system up with Bars Leak in the hopes of stopping it up long enough to unload the car onto somebody else. Used cars are a minefield.

Well, I tried using the magnet on the particles (very good idea BTW), and the good news is: It's not rust. So it's probably old coolant (silicates?), and it's coating the inside of the rad, the hoses etc.

I tried TeG's "flush" procedure, and finally the next refill was all clear. But I know that there's still a lot of the stuff on the inside surfaces; any way I can clean that up?

Thanks!

snipped-for-privacy@gmail.com wrote in news:1162403754.230815.248170 @k70g2000cwa.googlegroups.com:

If it doesn't discolor the coolant, don't worry about it.

Change your coolant every two years from now on, using the same stuff every time. This will help mitigate any ill effects from whatever goop there is left in there.