What flush/cleaner to use?

[PandaBear]

Last time when I replace the coolant bypass hose, I noticed some scales and crud in the area. I figure the next time I replace the coolant I will do a chemical flush/cleaner before I put new coolant in.

2 years later my radiator's top tank cracked, and the warning on the new unit said I have to flush and fill with distilled water mixed coolant or else no warranty.

So I am thinking about either the Prestone's Radiator flush or cleaner. Both seems like identical formula but the cleaner is stronger (need 2 rinse before putting in final coolant) and takes longer (3-6 hours) than the flush.

Which one should I use? I am leaning toward the stronger one, but are there side effects?

 

[The Critic]

I've used the Prestone Radiator cleaner product in my dad's van. I ran the water/chemical mixture for one week, then machine flushed the system at the school shop. After one week, the mixture that drained out was dark brown, and it completely clogged the coolant machine's filters.

 

[PandaBear]

Critic,

How is the van afterward? Running fine? Smoother or about the same? Was there problem with the van before the flush?

 

[The Critic]

Originally Posted By: PandaBear
Critic,

How is the van afterward? Running fine? Smoother or about the same? Was there problem with the van before the flush?

The flush was done about a year ago, and the van is still running fine. The cooling system has been serviced every five years (or so) since new, which is not frequent enough for Toyota RED. When the flush was done, the last fill of Toyota RED was only in the vehicle for less than two years, and it had already turned brown and yucky. The new coolant, Prestone All Makes Models, has stayed yellow green so far but still has some "chunk" in the tank, but nowhere as much as before. No problems with the cooling system otherwise, still running on the original thermostat, hoses, radiator and water pump after 16 years.