Prestone Super Radiator Cleaner Foaming?

[sciphi]

So I'm having a go at cleaning the cooling system of my mom's 1998 Subaru Legacy with the EJ22 2.2l engine. The radiator is pretty clogged based on the little amount of coolant that dribbled out of it.

Long story short, I refilled with water and added a bottle of Prestone Super Radiator Cleaner (not the 10-minute flush). I noticed the water in the radiator start to foam after adding the cleaner. Is this a normal occurrence, or did I just buy my mom a new radiator?

 

[HTSS_TR]

Prestone Super Radiator Cleaner did foaming in my LS400 coolant too, I'd done it about 10 years ago and the radiator is OEM with 260k miles now. I left it in the system for a week than completely flushed it out with the T-Flush.

 

[sciphi]

Thanks! So it's not just me. I'll drive and not worry about it!

 

[Boomer]

Lots of radiator cleaners contain oxalic acid (what makes rhubarb taste bitter) and it will react with carbonate deposits in your radiator (they come from using hard water generally). The reaction is similar in nature to pouring vinegar on baking soda. You'll elease CO2 gas, hence the foaming.

 

[sciphi]

The water in this area is basically liquid rock, so I'm not surprised now knowing that.
Originally Posted By: Boomer
Lots of radiator cleaners contain oxalic acid (what makes rhubarb taste bitter) and it will react with carbonate deposits in your radiator (they come from using hard water generally). The reaction is similar in nature to pouring vinegar on baking soda. You'll elease CO2 gas, hence the foaming.