Another ad nauseum radiator question!

[kevin p]

My rad is cool at the bottom and hot at the top after a run, and I'm virtually convinced it needs a new rad. However, I would like to try and flush the rad just to see if I can clean it out first before replacing it (along with flushing the system in all the usual places). Specifically, if I removed the rad, is there any chemical treatment I can use to clean it out, or is it best left in situ with some form of additive in the system?

Appreciate any help!

Kev

[roverv8stag]

I once saw the core of a radiator that had been removed due to hot and cold spots on the core and a less than efficient cooling system
There was no way in the world that any kind of "treatment" other than mechanical poking with steel pins was ever going to shift the crap that was seriously stuck in those core tubes.
I suspect that by the time the crud has got to the stage where it causes a blockage and the normal movement of the coolant wont shift it any further liquid treatment added to the radiator will just become part of the same blockage. The trouble being that the coolant like any other fluid will always find the path of least resistance and circulate nicely around the bit it can and ignore trying to get along the passages that are blocked.

[Lingen]

Kev.
Because the cores on the Stag radiator are horizontal they are particularly prone to silting up. However, there is no harm in trying a good flush. This is more likely to be effective if you take it off the car first. Get a flushing product, and follow the instructions (you will need to block the outlets somehow). The advantage of having it off the car is that you can shake it really hard to help free the crud. You can also get busy with a garden hose on the engine drain plugs but be prepared to get very wet! It means a bit more work, but removing the thermostat will allow a much better flow of water through the heads and block.
If you do have to replace the radiator, or get yours re-cored, do your best to get a four row offset tube core as they are the most efficient.
Mike.

[Hughesy]

You can also have the core "rodded". Yeah I am serious! Give it to a radiator shop and they remove one tank to gain access to the core and then they use a flexible rod to clean it out. Saves the cost of a new core. Craig

[roverv8stag]

You can also have the core "rodded". Yeah I am serious! Give it to a radiator shop and they remove one tank to gain access to the core and then they use a flexible rod to clean it out. Saves the cost of a new core. Craig

see above..."There was no way in the world that any kind of "treatment" other than mechanical poking with steel pins was ever going to shift the crap that was seriously stuck in those core tubes."

This service was offered to me 30 years ago in Australia for a standard cross flow Ford radiator. The suggestion was that the cores may be damaged during the clean out and they wouldn't know until they reassembled and pressure tested it.. I would have to pay for a new core AND the clean out service... I bought a new radiator.