Cleaning a heater matrix.

Don't forget that there are rubber seals inside the car on the heater pipes, whatever you put in must be safe with those seals. I like the idea of a back and forth motion of the fluid, whether central heating system cleaner would be safe? Read the bottles, but they should be safe, logically, since ch has rubber, copper and steel components..

When power flushing CH radiators they often vibrate the radiator to dislodge any crud. You may be able to achieve similar with a sheet sander (without sandpaper) by operating the sander in contact with outside of the heater matrix.

That would not be possible, the SD1 heater matrix is completely buried, removal or access involves taking all the interior forward of the seats out, start with the steering wheel, quite literally.

What about a water pump that is operated by an electric drill (£7 to £8 on Ebay), You could the pump any cleaning solution around for hours, occasionally reversing the direction. Intermittently pumping and leaving to soak may be better. If the feed and outlet were open ended hoses into a reservoir bucket you could see a change in the colour of the water when any cleaning agent is working. .

example

This one seem to be able to take fittings for a 1/2 hose

I doubt you could with an electric drill. That?s not the kind of duty cycle they?re designed for. Those pumps are also serious naff in terms of output.

Tim

Actually, the output on that eBay one actually isn?t that bad but it?s still a bad idea to run a drill continuously for hours. If it?s just to circulate cleaner/descaler a cheap submersible pond pump would be fine for continuous use.

Tim

I have used one to empty a large pond, the drill smelt a bit hot after an hour or so:)

Make sure the heater "heat" is on max. Some heater matrix have a tap on them, only fully open when heat is on max.

A bit of dishwasher tablet?

Those plastic bottles come in 0.5L, 1L. 1.25L, 1.5L, 2L and 3L. 2L and

3L will be bit unwieldy. Usually have other product in them. I would suggest 1L flavoured water from Aldi, still or sparking, 33p/L, bottle has nice shape for grip. Make the fill/vent hole in the bottom (top when used for flush) small or the structural integrity will be poor. Build the hose up to size of neck with insulation tape or glue them on to hose with silicone sealant.

I've got a WW2 stirrup pump that could do that.

What you need to get aerated fluid to rattle through it at a reasonable velocity. The meniscus effect of the bubbles is quite good at scouring away any loosened crud.