Will it work? What are the dangers?

[Heddy]

Replying to a 'blocked matrix' thread, I thought I might break into the heater hoses and tip a bottle of kettle descaler in. Pure madness? Or could it actually work? I've tried rad flush with no improvement. Your thoughts please.

[madeupname]

Hi, I ended up not doing it, but I had a two litre bottle of water with added Calgon. I'm pretty sure I read on here that it would make the matrix sparkle :D

[Daveluck]

#Heater matrixes last longer with calgon!

[Sprinter]

#Heater matrixes last longer with calgon!

Catchy tune! :D

[SCP440]

Descaling cooling systems can often end with a leak, the lime scale and debris that builds up over the years will clog up fine waterways but it also seals up small leaks.

My advice when ever you top up a cooling system is to use distilled water rather that tap water, it is not expensive and saves a lot of contaminants entering the system. Look at your kettle and that is what parts of the cooling system will look like if you use tap water.

[Daveluck]

Descaling cooling systems can often end with a leak, the lime scale and debris that builds up over the years will clog up fine waterways but it also seals up small leaks.

My advice when ever you top up a cooling system is to use distilled water rather that tap water, it is not expensive and saves a lot of contaminants entering the system. Look at your kettle and that is what parts of the cooling system will look like if you use tap water.

Doesn't the amount of limedcale build up and stuff in kettles and washing machines vary depend on where you live as you get hard and soft water?

[kaiser]

Descaling cooling systems can often end with a leak, the lime scale and debris that builds up over the years will clog up fine waterways but it also seals up small leaks.

My advice when ever you top up a cooling system is to use distilled water rather that tap water, it is not expensive and saves a lot of contaminants entering the system. Look at your kettle and that is what parts of the cooling system will look like if you use tap water.

This is misleading. Solids in the water is typically less than 1g per liter. The kettle sees a fresh inflow of perhaps 1000 liters a year, the cooling system after a couple of refills maybe 25.
The sediment in the kettle happens mainly at the heating element, where water boils off. A similar localised boiling does not happen in an engine, so most of the solids stay in suspension.

You can thus safely use tap water for your cooling system.

As for cleaning the matrix in situ. flush with a garden hose through the heater hoses, and change direction of flow from time to time. If you have access to compressed air, you can fill the matrix with water and give a blast of compressed air, to blow the content out under pressure. Do so with moderation, depending on the pressure. If you empty the outflow in a white bucket, you can see the results, I guess you will be fine without any descaler.

Let us know how you get on.

[dave lincs]

It is quite easy to take it out flush it then test it with boiling water

[Vanbursta]

Left descaler in mine for a couple of days, no harm done but tons of crud came out, flushed it thoroughly, used descaler again and got more crud, so it doesn't hurt to use descaler, eventually no crud and a very hot matrix at both ends.

[kaiser]

It is quite easy to take it out flush it then test it with boiling water

Many people have found it very difficult to get it back though. I have never tried, and I see no reason to try, unless you want to replace it.

[T-Cut]

Replying to a 'blocked matrix' thread, I thought I might break into the heater hoses and tip a bottle of kettle descaler in. Pure madness? Or could it actually work? I've tried rad flush with no improvement. Your thoughts please.

If a standard hose flush doesn't work and you want to keep the matrix if possible, then kettle descaler is the way to go. Descalers contain strong acids like propionic along with inhibitors to stop it attacking metals. This dissolves the calcium carbonate scale releasing carbon dioxide. It won't harm the matrix per se, and will shift a lot of the bound-on scale. If a potential leak is being sealed by limescale, then the matrix is scrap anyway.

Logically, heater matrix scaling to the point of blockage is the result of hard water top ups to a cooling system that's not fully watertight. Obviously, using deionised/distilled water is ideal. Scaling won't happen so severely in a watertight system with the correct coolant formula. Antifreeze contains calcium ion sequestrants to minimise limescale formation, even when using hard tap water. It's similar to Calgon in washing machines - a preventive but not a cure.

Limescale deposition is a temperature dependent equilibrium reaction between calcium bicarbonate, calcium carbonate and carbon dioxide in solution. Carbonate and bicarbonate are more soluble (safe) in hot water than cold, so the matrix tends to focus scale deposition because of the falling temperature across it. The antifreeze keeps the balance to the soluble calcium side of the equation, minimising the problem.

TC

[Heddy]

Thank you, some great answers. I was just concerned about the effect of descaler on rubber hoses, after all, it is a form of acid. Gonna do it :}

[T-Cut]

Most rubbers are resistant to acids - certainly the ones used in kettle descalant. But without removing the matrix, I'm not sure you'll get adequate contact unless you have a gallon of it.

TC

[roverbarmy]

Take off both rubber hoses. Pour in via highest hose using a funnel until it starts to leak out of lower hose. Lift each hose in turn to move descaler back and forth. Plug ends of hoses with a cork and leave to stand as long as you dare! Drain into a plastic bowl from lowest pipe. Backflush with water via a hose pipe. Refill and bleed system to test. Save the drained descaler/flush in case it needs another session. ( I hasten to add that I have never done this on a Rover but have done it on several other vehicles to good effect.);)