Technical Good radiator flush?

Can anyone recommend o good radiator flush? Think I have some scale build up in the cooling system and want to see if I can wash it out. Thanks in advance.

 

Permatex makes a heavy duty cleaner that works good.

 

Most of that stuff is a waste of time. Take it to a radiator shop and have it rodded out.

 

Professional cooling system de-scaling is done with Sulphamic acid for hard water, lime and antifreeze build up.
Oxalic acid is used to remove rust.
Sulphamic acid crystals are available at the hardware store in form of 'grout and tile cleaner'.
Oxalic acid crystals are available in form of 'wood bleach'.
Containers say what acid is used and its pure acid crystals with no other additives.
Available in 16oz. containers, which gives the right mixing ratio with water for the typical car cooling system with 3-4 gallons capacity.

Properly diluted, both acids are just as mild and safe as vinegar (acetic acid) and citric acid, but are more effective and cost is the same.
These treatments are safe to use with copper/brass radiators.
It is supposed to be safe with aluminum radiators as well, but I would do some tests first to determine how much reaction time is actually safe.

Oxalic acid used to be sold as a heavy duty 2-part cooling system cleaner over the counter until a few years ago by Prestone. Recommendation said to do this annually...

For best results it's essential to keep temperature at engine operating temp and to keep the flow going.
Instructions are to drain and flush first, then fill with the diluted acid mix and run the engine at fast idle or drive for 3 hours.
Do one acid treatment at a time, starting with the sulphamic acid, then drain and flush, followed by oxalic acid, then drain and flush.
The final step is to neutralize any remaining acid with a mix of washing soda and water and run the engine again for a while, then drain and flush and finally fill with coolant, but using distilled water instead of tap water, this time.

These methods really work exceptionally well.
I did both, back to back, on my old engine that had serious scale and rust build up.
Before the treatments and despite a new 3 core radiator, coolant temps easily climbed above 180 during the hot summer months with harder use.
After the treatments, the same engine now needs the thermostat to even get up to 180 degrees, even in the summer.

 

Thanks guys. Since I don't believe I have an overly clogged up cooling system I'm going to try the permatex first. Thanks for the hardware store fixes. Seems easy enough I'll try that if I still believe the system is clogged. And salt flats I agree a radiator shop is the surest way to clean out the radiator I was hoping to save that for last. Thanks guys!

 

My experience has been that the best way is to back flush the system. It seems to me that I have seen these kits at Harbor Freight. Install the supplied hose nipple in the indicated heater hose, warm the engine with whatever flush product you decide to use in it, then while running the engine alternate the flow from the water hose you have connected to the nipple. I always just pinch the hose open and shut. as you do that you will see the crud belching out the drain connected to the radiator cap. Alternating the water flow is important, try it without doing that then start, you will see the difference.

 

This is the kit I am talking about. HF no longer shows them.

 

Neat kit. I'll try and look for it. I always flush heater cores like that and it works well

 

Guy in town here has a small shop and he did my 56 buicks radiator for $50.Bruce.

 

Oxalic acid works great, I was able to find it at a local independent hardware store.



After you get the cooling system all cleaned out you may want to invest in a Gano Filter to keep it that way.

 

I do the oxalic treatment every 3 years and drive around for 2 hours then drain and flush.
It's perfectly safe with copper/brass radiators.

Over the counter flushes these days are non acidic thanks to EPA and mostly non-foaming soap, which works great to flush grease and oil, in case you had a head gasket leak.

After the mild acid flush, I use dishwasher detergent and drive and again drain and flush.

Remember to always mix coolant with DISTILLED water, to avoid mineral build-up from tap or well water.

 

I've used CLR to good effect.