I recently had an overheating issue and was told that my radiator core needed replacing at an exorbitant fee.
I bought a new radiator and then had my old one left over.
This is a (poor) picture inside the radiator cap.

I thought I'd see how clean I could get it.

If Napisan can clean "mud" out of nappies I thought it might clean "mud" out of a radiator.
I mixed one scoop of Napisan with two litres of hot water and stirred to dissolve the powder.
Fitted radiator cap and layed the radiator flat and filled it up.
Left it for 24 hours and then flushed it out with the hose.
What it didn't remove was the rust flakes as these won't dissolve and they would have to be mechanically removed.
But the result I thought was pretty good.
Could do the same with heads and blocks.

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Find a job you love and you will never have to go to work !

Nice!!

That did the job quite nicely. I wonder if it would do the same inside a dirty block...

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I fitted a head to the block, stood on its back end and filled it to top of water pump opening with a 1/3 molasses mix.
Agitated it daily with a pushrod, tipped out hosed it and refilled with molasses weekly, in 3 weeks it was clean as a whistle. And this block had sheets of rust in it from standing full of water for years.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

What do people think about CLR as a rad cleaner???

Cheers, Ian

CLR should be good as it removes dirt and scale out or clothes irons.
I didn't use it because I don't have any and I don't think is is sold any more.

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Find a job you love and you will never have to go to work !

Better to rod it out to be honest imho. The reason being that the little pieces of iron from the block, rubber from overuse of gasket goo, paper gasket etc etc will not be moved or dissolved by our puny chemicals in a lot of cases.

With so few tubes, the loss of one tube is a significant % of the total available cooling. It will not budge for love nor money with the low pressure of a hose, no matter how much froth and bubble you make, but it will dislodge with a piece of wire pushed through the core quite easily.

I would do this more at home if I had a pressure tester set up. I can solder and desolder the tanks quite easily, and butane torches with bottles are only around 35 dollars these days, but this is pointless if the tank is not tested for weeping or porous solder joints.

All the same it is not that expensive to have a radiator hot tanked, tanks desoldered, core rodded through, and then tank resoldered and pressure tested and painted black. Around 100 dollars.

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Carefully use of caustic soda and a flush gun is about the best you can do with it in situ. Other than that it's a r 'n r job. Also don't forget to flush the block etc before refitting the rad, for obvious reasons. Might sound stupid but its amazing how many people, including workshops, who don't.

It is quite easy to test a radiator for leaks at home, you just need an inner tube from a bicycle.

Thats not a bad idea...

The proper bungs and cap isn't that expensive, I just havent had a lot of reasons to pick one up. I think I will though.

Mick

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Quite the artist there Morris

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Wrong hose clamps Morris

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Yep, still available... try http://www.bunnings.com.au/clr-1l-calcium-lime-rust-remover_p4460670

Jim

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'68 Morris Mini 1310 A+ (Now Sold!)

Causing soda works well too at cleaning out radiators.

Doogie

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I won Hay once, here's the pic to prove it..


Hay, it's not about the car, it's not about the venue, it's about the people that come here. Peter Dwyer, Mayor of Hay NSW.