Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) New Roadster V6 Radiator

Me too. My Mulfab radiator has been in place since early 2008 and is absolutely fine with no sign of corrosion. I use the traditional blue ethylene glycol antifreeze.

This thread has reminded me that it’s time to check my coolant’s electrolyte properties. My coolant is a good 3 years old now. Ali rads can rot from the inside out owing to galvanic corrosion with increasing speed once the coolant starts to degrade, picks up sludge and becomes more conductive. A poor ground might be another reason for stray currents lurking in the rad too.

I’ve installed radiators built by both Peter and Simon and they were both excellent quality. Whilst constructed using a sturdy gauge ali, I would guess that the cores are just regular generic ‘off the shelf’ items. So I like to check for any electrolysis with a multimeter.



When the fizzing in my rad is around 0.3V (between ground & fluid) it’s time for a coolant change

Some sensible real life comment Rog rather than the BS from a certain quarter!

I don't know what you mean Graham


Just a thought… Before you install your new rad it might be worth just tracking down your engine’s ground strap and checking it has a good connection and is not corroded. If it were to be corroded your car could be using the coolant as part of its ground path. If there were any stray currents lurking in your coolant they might just start eating your new rad too.

Yep Rog is spot on there! If you are getting a leak to earth via the fluid the rad will become the sacrificial element or rather a sacrificial element. This is something that became very relevant with the advent of silicone hoses which totally isolated the rad, couple that with a rubber gasket to the top support bar on a Morgan and you have just successfully isolated your rad from ground.

If we are now specifically talking Morgan with an after market alloy rad then using the top or side mount brackets drill a small hole in a suitable place and connect an earth wire with a terminal loop and run the wire to a confirmed earth, as close as you can to the origin of your wire this will provide a better earth solution than the coolant. As Rog also stated the older the coolant gets the more likely that it is to hold a current, couple that with micro metal elements carried in the coolant and disaster awaits the uninformed.
Just change your coolant every two of three years and do a proper flush at five or six years as when you just drain the system passively some of those metal elements will remain in the water ways. Oh! and make sure you use the recommended grade of coolant for your car or a suitably listed improved option. Herein lies another complete subject!

Thanks Roger & Sewin, good tip on the extra earthing too