Radiator Return Connection Broke

Hello folks, first post here from a long time lurker.

Haven't found this posted anywhere else (please correct me if I'm wrong).

Been fixing lots of things on this wonderful vehicle, had the coolant sorted (nothings ever really sorted is it?) and got to the oily bits. Ran it up hot to look for oil leak origins when the radiator return hose started leaking at the radiator connection (looks like it was overtightened some point in history).

The following seconds featured a great deal of swearing and hot coolant avoidance to varying degrees of success.

After it finished spraying hot coolant everywhere (only slightly burning my hand), I cleaned down and tidied up to find that the plastic connector at the top of the radiator - return feed to expansion tank - had sheered off cleanly.

My question is:

Would a stainless steel spacer pipe (5mm O/D, 3.6mm I/D, 10mm long) fixed into the broken plastic connector and pushed/fixed into the side of the radiator housing be a sufficient repair in the sense of pressure and flow?

Would the reduction of internal diameter (5mm to 3.6mm) restrict the flow to the expansion tank? Does it matter as long as it flows and refills?

I'm obviously happy to replace the rad but £3 vs. £40 is preferable.

Opinions welcome.

Look forward to your thoughts.

I would just buy a new radiator as I expect the one fitted is the original one and probably full of gunk.
Also a good time to flush out the whole system and fill with fresh coolant.
You could try a bodge it but if it leaks again you could be stuck at the side of the road with no coolant or worse case cooked your engine…

For the cost of the OEM, you can get a solid aluminum welded one, lighter thicker core.  I did have to file the Bosses on the front down a wee but…

my car ran a tad cooler after installing it.

I tried to patch a tiny, tiny, hole on the radiator of a Lotus Elise I once owned (ahh, the days before children). Suffice to say, it failed, in a spectacular fashion and threw practically the entire contents of the coolant system over my windscreen at 50mph. Thankfully I was 5 mins from home doing a test of the worthiness of my fix. Lesson learned.

Ok thanks all, seems as though a replacement is the best way forward. Will look into ally versions, although all I can find is £100+, so perhaps not. We shall see.

There is also the thought of tapping a hose barb into the hole… I might experiment before committing for shits and giggles.

I'll let you know what happens.

Cheers for the responses.

The problem with trying to tap into it is that the plastic is brittle, and unless you can get a nut on the inside to hold it fast it is a exercise in futility.

On non-pressurized systems I have repaired that and had success, but because the tanks on these are sealed you can't get to the inside.

What I have done going forward is to use a 90 degree barbed fitting,  attach one side to the radiator and the other to the Expansion hose, this take the strain off the connection, and since then I have never had a hose or radiator failure on that bend.
Radiator return upgrade. | Volkswagen Owners Club Forum