Radiator drain tap

[lindatr4]

As my radiator does not have a drain tap it is my hope to fit one.

 

From the photo attached, I guess that the flat area at the bottom of the radiator is the place for it to go.

 

My questions are...

 

Does anyone have any experience of carrying this out?

 

What tap size & thread should I use after drilling the initial hole?

 

[RogerH]

Hi Linda,

Before you start consider how you are going to do this.

The skin in that area is very thin and simply drilling a hole and screwing the valve in will not work.

 

I believe you will need to solder a reasonably thick boss onto the skin and then tap that for the valve

 

 

When soldering the boss be careful not to melt the solder on the lower core seam.

 

Roger

[lindatr4]

Thank you Roger. As always you are fathomless pit of immense knowledge. Job for the winter months I think. I can then drain the system and renew the coolant at the same time.

[monty]

Thank you Roger. As always you are fathomless pit of immense knowledge. Job for the winter months I think. I can then drain the system and renew the coolant at the same time.

 

Just undo the bottom hose!

[peejay4A]

+1. Why introduce another potential leak point?

[mike3md]

+2, plus it drains the system much quicker!

 

Mike

[Lebro]

+1 for Rogers comments.

You would need to drill a clearance hole, then solder the tap in place, not a job for the faint hearted.

I would leave it as is.

 

Bob.

[RogerH]

Hi Folks,

removing the bottom hose is quite a simple matter and thus getting around a problem that can grow,

 

However I wonder what it would be like if the system was filled with boiling water

 

Roger

[ianc]

Or filled with Evans waterless coolant, which is a lot more expensive than conventional anti-freeze!

Ian Cornish

[peejay4A]

Answers to the above two questions:

 

1. Hot.

2. Waste of money.

[RogerH]

[stillp]

The way to drain via the bottom hose when hot is to simply cut it, from above - if you're draining the radiator it's worth changing the hoses at the same time.

 

Pete

[Don H.]

Gee.. I dunno... My radiator has a tap, and it's perfect. Easy to open, and easy to catch all the draining coolant in a container for proper disposal. Taking off the lower hose leads to a big mess.

 

I'd never dream of installing one myself, though. As Roger notes, it's gonna need a boss and heat management to protect the lower tank. I'd have a shop do it.

[stillp]

Mine has a tap, and yes, it's easy to catch the outflow, partly because it's so slow. The gush of water when the bottom hose is removed or cut through will do a better job of washing out the crud.

 

Pete

[RogerH]

. The gush of water when the bottom hose is removed or cut through will do a better job of washing out the crud.

 

.....and also the boot and two or three nearby cars

 

[stillp]