Rust colored coolant flush???

[nicholas]

I couldn't find anything in a search besides info about the rusty rear heater hoses, so here is my problem:

I have been doing a series of drain/fills on my rig with distilled water after doing the prestone/garden hose flush. I probably did the drain/fill/drain at least 8 or 9 times over a week long period because I ended up doing the tap water flush twice since it looked like the drainage wasn't completely clear.

Each time I did the fill/drain, I drained both the Radiator petcock and the engine block plug (I can literally remove/install the engine block plug with my eyes closed or in the dark), and I ran the engine until the brand new OEM thermostat was open with both the front and rear heaters running.

When I collected the water after the drainings, the first 6 drains had some of the notorious gray clay looking residue that settled to the bottom of the jugs over time.

However, the last few drains (after the second tap water flush) came out orange-ish and later had a rusty colored residue that settled to the bottom of the jugs which confirmed my fear that I must have rusted something in my cooling system.

I read in e999's writeup that he wouldn't hesitate to leave distilled water in a system for a few days to ensure a thorough flush, so I must have mistakingly figured that a week wouldn't be too much.

So my question is do any of you have any guesses what the most likely source of my rust is? My rear heater lines look ok from the outside, and I just replaced the PHH w/ silicone. The PO had the HG replaced by the lexus dealer about 40K/3.5yrs ago.

I'm worried that I just fubarred a perfectly good 1FZ. Can anyone calm my fears?

[nicholas]

Has anybody had this problem? I might add that this is not a case of mixing Toyota Red and Prestone green. I put in several flushes of distilled water and it came out with rusty sediment in the collection jug.

[gotmud]

Originally Posted by nicholas

I'm worried that I just fubarred a perfectly good 1FZ. Can anyone calm my fears?

I had similar problems on my '94. It took several flushes using 2 bottles of Prestone Super Flush before I got the bulk of the crap out of it. Even now, a year later, I still have a little bit of sediment. I just flushed mine again last week and see that I have what looks like little pieces of rust floating around. So far, it runs just fine and never over heats.

I'll flush it again in 3 months and re-evaluate.

BTW, don't worry about running just water for a while, you'll be fine. I wouldn't tow or take any long trips like that though.

[nicholas]

Thanks for the reassurance. I only filled/flushed then drove short periods (<7 miles) with straight water in the system. The thing that was weird is that the water drainage was clear in after about 4 or 5 drainings, but during the last set of drainings they started to get tinged with rust residue, but no gray clay residue. I guess I'll just keep up on the annual flushes, and not worry about it.