Draining a 300 Tdi radiator - installation of a drain valve

[Troll Hunter]

Hi, All,

I'm getting really fed up with a regular wet arm, as a minimum, when draining my radiator. I've read various threads that recommend using a tube through the header tank and down into the make up/expansion line connected to the hose connection at the bottom of the rad. I have used this method with varying success. I remember seeing a thread that mentioned a custom made rad that had a valved drain point added to the bottom connection, possibly with the hose connection slightly lengthened. This seems to be an ideal solution, if you're buying a new rad anyway. I'm not, but I'm wondering if anybody has fitted a T-piece low down in the line that goes to the header tank, with a drain valve on the "vertical leg" of the Tee. I think that this configuration should be capable of draining most of the coolant.

Has anybody done this? Does it work? What are the problems? Should I not try it? Is there a better way to avoid a wet arm?

All views, experiences, recommendations and advice will be very gratefully received. Thank you.

Mike

[cookie64]

I have also been pondering this question for years, would be interesting to see any examples of peoples work

[Chicken Drumstick]

Can't really see a problem with just pulling the bottom hose tbh. It's not as if you need to change the coolant all that often anyway.

That said, I'm sure you could be creative with something like this in the bottom hose. Or an aluminium version. Although it might just be another area that could cause a leak.

[reb78]

Can't really see a problem with just pulling the bottom hose tbh.

Apart from the fact it goes everywhere, soaks where you need to lay under the car to do bits and leaves you with a puddle of stuff that's poisonous to cats and dogs that you need to clear up.

[bushwhacker]

That drain down plug/tap should be a standard fitment.

Nice to have for reasons mentioned.

Would it sell who knows but wouldn't mind one.

[Retroanaconda]

A piece of pipe with a threaded boss fitted that would take a Difflock Drain Plug type fitting would be good.

No valve or hosetail to get damaged, and to drain you just remove protective cap and fit the drain hose on which starts the flow automatically.

[muddy]

Something like Simons X-fan but with a bung/tap instead of the fan switch?

[Bowie69]

You could just fit the x-fan and remove the switch to drain!

Or put a temperature sender in there

[GW8IZR]

I had an Austin Cambridge with a drain tap in the rad, when you opened it there was a bit of a squeak as the brass moved, no water ever came out of it as it was too full of rusty crud :-)

[cookie64]

I like the idea of coupling one of Si's X-Fan hose adaptors with a diff lock drain plug, good idea, maybe a sales combo special would go well.

[Reiny]

I have a very simple fix. It works every time. All you need is a length (about 2 metres) of flexible hose that fits inside the thin end of the bottom hose (i.e. the end that goes into the reservoir. If I recall correctly, a hose with a 10mm inner diameter is perfect. What you need to do is this:

1. Use afore mentioned hose to siphon off the contents of the reservoir into a suitable container.

2. Remove bottom hose from reservoir and lift it up as high as you can to reduce / eliminate spillage

3. Insert afore mentioned hosed into the bottom hose and push it in as far as you can (a foot or so would do it).

4. Siphon off into container. This should empty approx half the radiator.

5. Remove flexible hose from bottom radiator hose. Keep the radiator hose in the highest position you can.

6. Position the container under the vehicle in such a way that it is in the vicinity of the radiator's bottom hose.

7. Aim and lower bottom hose into the container.

8. Let gravity do its job.

Radiator will be totally empty with no mess or spillage.