I have no idea what's been through these pipes then. They're a bit of a state.  Unless they've rusted from the outside from salty air maybe? 

I found a pipe that i'm hoping is going to fit. Different part number and one extra smaller outlet but if it fits, not a problem to blank off. 

Found all the parts except a mounting flange to knock up a custom setup if it comes to it. 

So i've been able to do a few bits over the last week or so. Got the metal cooling pipe from a different polo, the mounting face fitted perfectly, just had to cut off the end section as it wouldn't fit on the bottom hose. As the bottom hose would not fit onto the pipe i got, i got a new bottom hose. Used some flexible pipe with correct id for either end and it works great. Fitted all these, put some water in the system, left for couple hours to check for leaks, all good. Topped up with antifreeze, left overnight to check for leaks, seems fine. Got radiator filled to just shy of the max line, fired up and still seems fine. Taken it for a run today, good couple of miles, mostly 40mph roads, seemed great. Will try it down motorway, next junction and back, probly tonight. 

If all goes well, will post list of all the parts i used. 

Thanks for all your help and patience dudes. Very much appreciated. 

 

So this seems to be holding up nicely. I did check on my first test run and the water/coolant just looked like rusty water after a few miles. I put a flush in the system, drove round for a couple days making sure i put the heater on full blast, blowers all that jazz. Drained it, flushed again with hose until it came out clean, filled it back up and a week later, still looks good. 

 

So if anyone else has an issue with that coolant pipe on the back of the engine, the one i used was this one:

Part number 036121065F

This is NOT the stock part for the breadvan i have but it does fit perfectly once cut down. 

I had to cut it off pretty much where it curves. Left the other two outlets untouched as they fit the hoses from my heater matrix. 

Next issue was the bottom hose wouldn't fit as the ID was much bigger than the metal coolant pipe and being moulded, it wouldn't fit onto the metal pipe. 

So i used this:

https://www.carbuilder.com/uk/vulcoflex-flexible-coolant-hose-32mm-28mm-id-x-475mm-long

As the bottom rad outlet was bigger than the metal pipe. Fitted great with no sharp kinks at all. 

Also got this:

https://www.justkampers.com/052-121-091-a-coolant-flange-gasket-diesel-vw-t25-1979-1988.html?fee=1&fep=23887&utm_source=google&utm_medium=cpc&utm_campaign=PLAs&gclid=EAIaIQobChMIsvSL5fi36QIVyYXVCh1WuwPlEAQYASABEgKvl_D_BwE

This coolant gasket fitted perfectly although making one out of gasket paper would have worked too. 

Now it seems to be working great. Have only done a short stint on motorway as we are currently still on lockdown but will be taking it out for a longer run as soon as i'm able to. I have run it around town, just pootling at 30-50mph as that used to tax the cooling system on my old bready. So far, seems to be fine. Will report back once a long run on a hot day has been done.

 

This is the flexi coolant hose in place. Fitted perfectly, no sharp bends to restrict flow.