Old heater radiator

[stupiddad]

I have spent hours flushing my heater rad in my Mk 4 Cortina using different products including the Harpic with phosphoric acid and never achieved any significant increase in flow or heat transfer.

The last straw was rusty water in the passenger footwell so I bought a new rad from demister man, took ten minutes to fit requiring only marginal relieving of the holes in the front plate.

It came with a strip of self adhesive foam and I used some halved pipe lagging to ensure a snug fit which I taped on with duct tape.

When I was bleeding the topped up coolant sysem I cracked the jubilee on the top heater pipe which is the highest part of the system; I was astonished to see a jet of water emerge rather than a rusty trickle and the demist vents issued  hot rather than mildly warm air .

My advice is don't bother messing around with an aging heater rad buy a new one, it will keep the interior of the car dry and warm and keep the windscreen clear of fogging and condensation. It is easy to fit needing only a crosshead and a flat screwdriver on mine. If you do remove your heater rad for any reason make sure you unhook the battery first as it comes close to the ignition starter solenoid when drawn from the heater box.

Nice warm toasty feet too.

[Ray]

you can clean the matrix quite easily, removed from the car, buy some water based de ruster, Halfords used to sell it, but you can get it online, its a concentrate you mix about 90% water to, fill the matrix, leave to work over a day or two, repeat if necessary, you will need to then pressure test it and if need be, have it repaired, my personal experience of demistermans matrix units is not good tbh, but just a personal experience, his mk1 escort ones are a diabolical fit, and you hav1e to file out the pipe holes, but the cored area is around half of that of an original unit

as an aside, this is also excellent for cleaning the water channels in heads and blocks on engine re builds, you just need more of it and a tank to submerge them in

I have actually done an entire water system in situ with this method as well, and it does work, however, once done, you need to replace things like the water pump as it will have likely to attacked the seals