Cleaning heat exchanger

[Restoration man]

I’ve striped my entire cooling system on both engines, I’ve cleaned my cores with rydlime but the tubes don’t look very clean inside , the outside looks ok but inside the tubes they don’t look that clean , there not blocked but look like they still have some scale or something on them , I’ve read on here it’s best to avoid brick acid something to do with etching the tubes ,but it is an old boat it’s 1976 so has prob had brick acid used in the past? , so what’s the next thing to try? , the ridlime didn’t do much , so my choices are
1)use the brick acid anyway ,
2)poss get brass riffle brush but would this scratch the tubes and cause more problems?
3) would Coca-Cola work ? As kid we put 2p coins in it and they came out really shiny??
4) try an ultrasonic cleaner? , I’ve been thinking about buying a large one for while , I’m sure I would find other jobs for it
Anyway any advice would be greatly appreciated

 

[Montemar]

the tubes are probably brass. They may not look like new but so long as they do not have a layer of scale they should be ok

 

[Plum]

I’ve striped my entire cooling system on both engines, I’ve cleaned my cores with rydlime but the tubes don’t look very clean inside , the outside looks ok but inside the tubes they don’t look that clean , there not blocked but look like they still have some scale or something on them , I’ve read on here it’s best to avoid brick acid something to do with etching the tubes ,but it is an old boat it’s 1976 so has prob had brick acid used in the past? , so what’s the next thing to try? , the ridlime didn’t do much , so my choices are
1)use the brick acid anyway ,
2)poss get brass riffle brush but would this scratch the tubes and cause more problems?
3) would Coca-Cola work ? As kid we put 2p coins in it and they came out really shiny??
4) try an ultrasonic cleaner? , I’ve been thinking about buying a large one for while , I’m sure I would find other jobs for it
Anyway any advice would be greatly appreciated

As Montemar said, if there is no appreciable reduction in diameter of the tube bores then I would do nothing. If you don't already have one, suggest you make of buy a coolant preasure tester and test to 25% higher pressure than the pressure cap rating for 20mins

Www.solocoastalsailing.co.uk

 

[colhel]

What about this stuff?

 

[starfire]

I’ve striped my entire cooling system on both engines, I’ve cleaned my cores with rydlime but the tubes don’t look very clean inside , the outside looks ok but inside the tubes they don’t look that clean , there not blocked but look like they still have some scale or something on them , I’ve read on here it’s best to avoid brick acid something to do with etching the tubes ,but it is an old boat it’s 1976 so has prob had brick acid used in the past? , so what’s the next thing to try? , the ridlime didn’t do much , so my choices are
1)use the brick acid anyway ,
2)poss get brass riffle brush but would this scratch the tubes and cause more problems?
3) would Coca-Cola work ? As kid we put 2p coins in it and they came out really shiny??
4) try an ultrasonic cleaner? , I’ve been thinking about buying a large one for while , I’m sure I would find other jobs for it
Anyway any advice would be greatly appreciated

I found a local diy store that sold lengths of threaded rod, studding.
One was a good fit for clean tubes, but acted like a blunt file for scaled ones.

Bit like cleaning locomotive steam tubes, easy but when you have 300+ tubes per heat exchanger, time consuming.

 

[Bandit]

What engine?
Normally take the cooler stack use one of those windowsill plastic rectangular planter pots and soak cooler stacks in Rydlyme, mix 50 % 50% with water , it should froth like hell to start with and when it stops frothing if any lime scale is still present it would mean the Rydlyme is chemically spent , refresh with new mixture and start again. It should look like new after this.

 

[ARE]

Cummins/fleetguard restore or restore plus is perfect for cleaning heat exchanger and the whole cooling system. I have used it for a number of years.

 

[Restoration man]

What engine?
Normally take the cooler stack use one of those windowsill plastic rectangular planter pots and soak cooler stacks in Rydlyme, mix 50 % 50% with water , it should froth like hell to start with and when it stops frothing if any lime scale is still present it would mean the Rydlyme is chemically spent , refresh with new mixture and start again. It should look like new after this.

Perkins t6.354 mgt, don’t really want to waste anymore money on ridlyme as I’ve already tried that and the scale is still on the inside of the tubes , hence me thinking of other options , poss small brass brush might break up the scale , I’ve gone to lot effort to strip the complete cooling system so want it as clean as humanly possible

 

[Andrew M]

I've done the same with our exchangers and gearbox oil coolers during this stay out the water. I rodded the heat exchanger tubes with threaded studding, got 2 diameters, I think 1 was 2.5 or 3 mm which was great for clearing/cleaning out any blockages,deposit build up or restrictions, then followed that up with the 2nd slightly larger version which nicely cleaned the whole tube,. I did then follow up with a rydlyme soak,. They came out looking like new and I now know the entire system is back to new condition internally.