Talk Morgan Forums Morgan Sports Cars Maintenance & Servicing Cleaning water jacket....

Thermocure is the stuff. As far as the filter is concerned, I'd rather have the debris that breaks loose blocking the filter than the radiator. Use the filter while you are going through the cleaning process, you can remove it once you're done if you want. Most everyone I know uses the nylon stocking. Little or no cost and just removing one end of the radiator hose to install and remove.

It's strange - I've been dabbling with old cars most of my life and never heard of one, or the nylon stocking trick!

I might try it when I'm running the thermocure, but then flush both the rad and block afterwards.

Anyone else running a top hose filter?

Put the thermocure in over the weekend, left it in until today, including a drive to work and back on Monday.

Prior to using, I'd flushed the system back and forth, through thermostat housing, through heater pipes in both directions and radiator top to bottom for about two hours - water was coming out clear through every pipe.

Water I drained out today was black! Seems to have done an amzing job. The visible block through the thermostat housing was previously the usual rust colour, but was now very clean and no rust. It's not scrubbed it back to bare metal but made a substantial difference.

The water flow is much improved - before the treatment I put a hose on the manifold take off, and by blowing really hard could just get some air through the bottom radaitor hose. Today, if I was more talented, I could probably get a tune out of her! Air flow has greatly improved.

Just waiting for the postie to delivery a new water tap (i've decided to remove the bypass system and fit a straight on/off tap) then I'll get her topped up and check hoses.

Will probably do it again just before winter, but certainly recommend it. Thanks for all the advice.

Glad it worked for you. I know of people that have left it in for a few months on a really rusty system. Both this and the cooling system filter idea came from old car (1920s) groups I belong to.

Never, ever, use caustic soda if there's any aluminium anywhere in the cooling circuit. You might have a cast iron head & block but don't forget thermostat & water-pump housings and the radiator.

It used to be used to decoke engines but problems became clear when aluminium became common in air-cooled engines (most motorcycles) in the 1950s. Stay safe and used a solvent designed for the job

And be very careful if you have caustic pearls or flakes. It is hydroscopic and will burn through exposed flesh. It is a very nasty chemical.