I had a '90 Topaz and the damned things are like roaches. Not exactly a *good* car, but they are hard as hell to kill and run forever with routine maintenance. I think I'm going to try this vinegar trick on my sat-for-twenty-years-nailhead and see how much **** comes out. That is, if I ever get around to sorting the electrical and making it run without burning itself to the ground.
Vinegar is just an acid wash. I have some old-stock Prestone radiator cleaner that comes in a double can. Top part contains acid crystals, bottom part contains neutralizer. The acid part is very strong--- you don't want to inhale the stuff. Instructions call for draining system and filling with pure water plus the contents of the top part of the can. Run for at least 2 hours (or days if you prefer). Drain system, add fresh water and contents of bottom part of can. Run again. Drain and fill with water. It suggests doing this annually.
Yeah, be very careful here. Loosening rust will plug up your radiator just like an oil or fuel filter. The tubes inside the radiator are fairly small and restrictive, and are easily plugged by small pieces of debris
The old Prestone Cooling System Cleaner was oxalic crystals (9 oz) and washing soda (2 oz) to neutralize. Oxalic crystals are available in form of Wood Bleach from the hardware store. Works quicker on rust than vinegar or citric acids and is still safer and not anywhere as corrosive as muriatic (HCl) acid. For mineral and lime deposits from hard water use Sulfamic crystals, available in form of tile/grout cleaner. It's even less aggressive than oxalic acid.
I flushed my older 302 with Aluminum heads and radiator using Vinegar. What I did was drain the system, Pour 1 gallon of vinegar and then top off with water. Drove it around for about 20 miles. Then I removed the upper radiator hose and stock the garden hose in the radiator neck. I flushed it for a good 20 minutes, then ran it with the water flowing this way for another 1/2 hour. wanted to make sure I got all the vinegar out because of the aluminum heads. Then flushed it for another 1/2 hour. Filled it with a product like Evans that i get form the motorcycle shop and it's been that way for about 3 years now, no problems and water looks pretty good.
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