Do I really need to use a radiator "flush"?

[wavinwayne]

What if I just drain the old coolant & replace it with an equal amount of new 50/50 mix? Is "flushing" really necessary?

This would be on our '97 Expedition & I would be using the regular ol' green Motorcraft coolant that it calls for.

 

[Kestas]

You won't get all the old coolant out. It's the same as dropping the transmission pan to change the fluid or using a turkey baster to change the power steering fluid. Some people are okay with it. I like the turbulent action of a flush to sweep out any loose debris. The preference is yours.

 

[JHZR2]

mercedes-benz calls for a citric acid flush in their systems.

I do one every time I swap coolant (every year), and my 83 still has the original radiator!

JMH

 

[TR3-2001SE]

Does this mean I just need to add oranges to my distilled water when I flush? I really am serious where do we get this citric flush stuff? I still have the original radiator on my TR3 but it only gets distilled water at flush time.

 

[Mr Nice]

As long as there is no rust or grime built up in the cores, there really is no need to use a flush. Drain it every 30,000 miles, you will never have to worry about radiator problems.

 

[Ray H]

Prestone's flushes use citric acid (sodium citrate). I agree with LT4 Vette - if there's no sedimentation or scaling, chemistry's not necessary. I do recommend flushing with clear water (preferably distilled water - it's cheap at WalMart) until the effluent drains clear. Keep your heater valve pegged on the "Hot" setting to flush the heater core and idle the engine until it warms up to normal operating temperature between drains. You can judge this by how hot the upper radiator hose is - it'll be H-O-T once the thermostat opens. Since even opening the block drain plug(s) won't entirely drain remaining water, use an antifreeze concentrate instead of 50/50 premix. Then adjust the concentration with distilled water and one of the coolant hydrometers (Prestone or Victor come to mind) to establish a verified 50% (or whatever percentage you prefer for your climate) concentration. Time consuming and boring, but at least you'll know it was done right when you're finished. (and you won't have to wonder if any of the flush chemistry remained behind to screw up the new coolant's pH and corrosion inhibitors)