Jump to content

Draining a 300 Tdi radiator - installation of a drain valve

Recommended Posts

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.


Link to comment
Share on other sites

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.


Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...

Important Information

We use cookies to ensure you get the best experience. By using our website you agree to our Cookie Policy