What is the best way to flush out my radiator

HMD,

Do you have detectable scale deposits in the radiator tubes? If you suspect scale, you'll need to do an acid flush to loosen all the scale deposits. Immediately after the acid soak and flush, you'll need to neutralize the acid, then flush the system with plenty of cold water. I like to flush in a reverse direction, but I don't really know if that matters as much as flushing for a long period of time to completely remove any debris from the system.

If there is scale, even a flush may not clean it satisfactorily. If you get adequate cooling, you're probably O.K.

The flush will be most complete if you keep the heater on full heat so the hot water valve remains open ('87 and later cars) and if the thermostat is removed before the process is started. I also like to remove and clean the overflow reservoir, but it isn't absolutely necessary. Just make sure the system is flowing nothing but clear water before you stop the process, and drain all the water before refilling with antifreeze solution.

If you have a scale problem, you might want to use deionized or distilled water to mix the fresh solution. Mineral deposits in tap water can start the scale formation all over again.

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Later,
Vader
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"Make Me Bad"
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OK I know that flushing the cooling system is worth while and that reverse flushing is better, but how exactly do you reverse flush it?? I am really in the dark on this one.

Kevin

Rads wear out.

The easiest thing to do is repace it. Not now, right now.

How old is your rad? I had one flushed once and it opened up a whole bunch of leaks that the scale had sealed.

A rad guy showed me a trick once. If you can easily, on the engine side, bend and disintegrate the fins the rad is not worth it.

I replaced a bad rad and, bingo-bango, the engine ran cooler AND I got better heat.

Mr Gets His Hands Dirty

if it's dirty or clogged either have it tanked or replace it. the cost of having it tank cleaned will go a long ways towards the price of a new radiator

Where can you buy this acid flush at? I have a recently new radiator and flushed it a few months ago, and when I take off the radiator cap, I see little stringy particles floating around. I don't know that this stuff is. They just did a regular flush going the way the coolant flows. I was thinking of doing the reverse flush at home with the prestone kit. Is that a good idea, and is it worth it? Or is it just a waste of money? And, do you know what those floating stringy things are in my coolant?

thanks

Particulate matter and foreign objects are different than scale. You may need only to thoroughly flush your system to remove sediment and foreign matter. Scale formation is best removed in an acid dip, but may not do anything for foreign matter.

I'm guessing by your dscription that you may be seeing fragments of gaskets, thread sealants, and other insoluble material that would best be removed with a cooling system cleaner, such as Prestone Super Flush, Gunk Radiator Flush, or an equivalent, non-acid cleaner. These milder cleaners will suspend most sediments and particulates, and don't require a neutralization step.

Incidentally, according to th efactory manual, you are supposed to perform the cooling system service every three years or 36,000 miles, whichever comes first. If you use Dex-Cool, you can extend that to five years/100,000 miles, but still have to monitor for pH and total dissolved solids (TDS) using a conductivity probe or sampling.

personal opinion partly based on my experience and what i've read here, if you have dex cool change it to the old fashioned stuff.

gearhead0384: I would assume they reverse flush to send the water through the opposite way, to "go against the grain" so to speak, so it would aggitate the buildup more.

If you want to do an acid flush, you can use household vinegar. My professor was telling the class to reverse flush with vinegar, then with some other base to nuetralize(cant remember what it was).