Triumph Herald Cooling system flush and replace

[keith417]

My 1963 Triumph Herald 1200 saloon's radiator coolant needs replacing and the radiator needs a good flush, probably a lot of crud in it. Haynes manual talks about 'leaving a hose running in the radiator cap orifice for ten to fifteen minutes'. Presumably this is using normal tap water, but elsewhere I read tap water should not be used under any circumstances. Also some refer to using a Speed Flush or cleanser. What should I use?

When it comes to refilling the system, what is best to use. Haynes says 'rainwater'. I've got plenty of that in butts. What about anti-freeze? I've read some anti-freezes are only for modern cars. What would be best for my old 'gal'?

Any tips on emptying existing coolant as well would be helpful.

Any help, advice etc. appreciated.

[RobPearce]

There's a fair bit of nonsense talked about coolant. I'll address your points individually:

1 hour ago, keith417 said:

Haynes manual talks about 'leaving a hose running in the radiator cap orifice for ten to fifteen minutes'. Presumably this is using normal tap water, but elsewhere I read tap water should not be used under any circumstances.

Tap water is considered inadvisable as coolant. This is because it's often quite hard and will cause scaling up of the system. However, that only happens when it's left in there and repeatedly heated and cooled - there is no problem at all if you're using it to flush the system and then draining it out.

1 hour ago, keith417 said:

Also some refer to using a Speed Flush or cleanser. What should I use?

That depends how badly clogged it is. If you're just doing regular maintenance, sue plain tap water. If you're tackling an overheating problem that you suspect is due to the system being clogged up, fill it with dilute washing soda for a while, then drain and flush thoroughly.

1 hour ago, keith417 said:

When it comes to refilling the system, what is best to use.

There are opinions on this. Personally, I use tap water but I boil it first. This removes most of the hardness. You could use rain water but if your water butts are as stagnant as ours then I wouldn't let that stuff anywhere near my car. Always use blue (glycol) antifreeze - NEVER use the red OAT stuff.

Old coolant should not be chucked down the drain but rather you need the correct environmentally friendly disposal. Check your local council's web site to see whether they provide such a service.

[Rosbif]

I was on the point of replying when my computer said Rob had replied and as he is almost* always correct I thought it better to read his reply first.

* I put that in to stop him thinking he is perfect and getting a swollen head 😁

I assume the 1200 has a drain tap/plug on the engine block like the 13/60, if so open/remove it to make sure water runs out. It can get blocked so prod it with a bit of wire to help.

On my 13/60 I also used a garden hose connected to the heater valve to put pressure in the system to flush it through. Open the heater valve, of course to do this and it will also flush the heater. Flush through in both directions while you are at it. On mine the heater valve was completely gunged up and didn't work so I replaced it.

Other than that, when filling leave the heater valve open and then run the car to get any air locks out.

[keith417]

Thank you Rob and Rosbif. Great detail. Much appreciated. It sounds straightforward. I may have more questions when I get round to doing it, which may be a day or so yet. 

[Rosbif]

17 minutes ago, keith417 said:

It sounds straightforward.

It is, as you didn't mention any overheating problems I assume it is just a 'refresh'. Did mine a couple of weeks ago, I took the old liquid to my local recycling depot for them to dispose of correctly.