coolant corrosion

[zzebby]

I have a '95 LT1 case iron engine, walker brass rad and lots of aluminum on the front of the engine. Perfect storm for dissimilar metal corrosion.  It has sat for several months with just water in it as I work on wiring and headlites and so I drained it. Very yucky black green goo. I flushed with the garden hose but still see gobs of semi solid white corrosion in around the thermostat housing. Any suggestions on flushing and what to put in for coolant.  The premixed or straight antifreeze...and are they all the same ?

[Arnold]

My .02.I don't flush anything anymore. At least not with chemicals. Too many bad experiences. In this case..plugged up rads..and worse..heater cores.
Hot water and the garden hose is all I do..and would do. I have had better luck with pouring boiling hot water in them..letting that sit..then flushing that out. When you first fire it..fill it with boiling hot water and get that out of there fast. Re-fill it and drive it with plain water for awhile..not long. Then just use 1/2 water and 1/2 antifreeze. Me..personally..it is a lot easier to put a pump and 'stat on it when it is out. Pumps and 'stats that have been sitting around don't like me. I think that some of the pre-mixed stuff uses distilled water.

[1800guy]

I agree with Arnold 100%.  A potential problem with harsh cleaners is the chance that old deposits may start to come loose but not all come out when drained - then finish breaking loose later and really jam things up when you may not be vigilant.

If in fact 50/50 pre-mix has distilled water that is not good.  Water that has no minerals will find them to re-plenish itself - inside your engine.  Around here, 50/50 is about $1.00 or so cheaper than full strength a/f - but of course you need twice as much of it.  Like buying lite beer...

[Arnold]

Of course the coolant itself does become corrosive after a few years(there are testers).
When I only changed sbcs's for a living in the early 80's(actually it reached the stage where I only changed sbc's that had been damaged by sloppy rebuilds etc. haha)((out went the butchered ones in went used ones that had not been touched..day in day out)) I used to see 305's that were damaged by bad coolant.These would be late 70's 305's. Not only were they notorious for soft cams. They were notorious for the top of the block right at the head gasket to head being soft.Never saw this on other engines. People would not change their antifreeze..then one would come in with a bad head gasket.Nope. The block was eaten away right there.
Sheesh..they had only been in production for 8 years or so!

  I could not believe the first one I saw! I never even saw ONE engine like that when I worked as an automotive machinist.And I worked for a very large engine rebuilder.Even 350 heads (as well as other blocks)as they got thinner and THINNER castings over the years did not do this(mind you they cracked more often).

  These were Canadian engines.Don't know if that problem was U.S. too.