How effective is backflushing the radiator?

[Aethelric]

I'm thinking of fitting a new radiator, or maybe just backflushing the existing one.
Does anyone know if the crud just sits there, and so can be removed by backflushing, or is it deposited on the piping inside the rad, (like scale on a kettle)? Anyone ever opened a rad?

Dave

[The Great Pretender]

(like scale on a kettle) that is caused by hard water.

It is like colesterol.
'Crud' will solidify over time.

[Simon Jones]

When I flushed mine, I didn't get much stuff coming out. Either it means there wasn't much to remove, or it wasn't very affective. I tried some coolant flush powder, but that is brown in colour so you cant be sure if the brown water coming out is the crud or just the stuff you poured in!. I think I read a trick about filling it with coca cola which tends to shift 'subborn stains' but I've not tried it myself.

Now, if someone with a brand new rad could carefully measure the exact amount of water taken to fill it to the brim with the bottom outlet plugged, then we would all have a benchmark to test the capacity on a used rad to compare how much blockage has occured. Volunteers?

[nfn]

Excuse my ignorance -- but how do you backflush the cooling system? On my old Saab I used a kit like the one down at the bottom of this webpage:
http://www.prestone.com/products/accessories.php
I just followed the instructions on the box. The car ran nice and cool for a few hours after backflushing, then overheated. I think I disturbed more crud.

[vanvliet]

Lost the plot on this earlier but what turned out to be the cheapest source of a pukka rad and how much was it ?. I know that rads can also be made up to a spec.( bigger bore pipes which are less likely to crud up) Would it be worthwhile doing this ?

[dandywarhol]

I think you're idea's good Simon but I wonder about the quality of some of the aftermarket radiators, especially if they've been overhauled and retained the top nd lower tanks.

A way to determine a base to work from would be to get a Mazda unit, measure the capacity AND time the emptying process.