Ha, another update. Not one I necessarily wanted to do because the car was happy and running well. But it happened and just have to accept that stock components are not always going to be the best for what I do with this car.
Long story short, the radiator let go on my way home from a game of tennis and a sunset cruise with another E36 friend.
I hate wasting time, so got the car towed home that night and pulled the old radiator out the following day, and went to collect the new one.
Stopped by NDT Racing:
And picked up the new radiator, as well as a bunch of other parts to refresh the cooling system. There's obviously no point in replacing with stock components, so I opted for a bigger, full aluminium radiator to help keep the temps down and minimize the risk of another failure:
Changed the fan blade to a 325 TDS fan and replaced the viscous (which I ended up taking out and putting the OEM viscous back in). I'll do an electric fan at some stage but for now the viscous does a really great job of keeping the car cool.
The radiator was not just a bolt-in straight fit upgrade, I did have to do some modifications to the shroud to make it work because of the different sizing.
Took a bit of time but eventually got everything in, including ditching the stock coolant bottle and relocating the new VW coolant bottle to the passenger side of the engine bay. This is moves the bottle away from the stock location close to the exhaust manifolds, and simplifies the cooling system quite a bit in terms of the length of the coolant hoses, and make bleeding the system a breeze. They're also less prone to failing and pretty robust. I'll wire in the level sensor when I get a chance, just need to find a used pigtail and extend the harness for the plug and the level sensor will work like factory. Also ignore the ratchet intake.
Went to bleed the system, but after an hour of trying it just wasn't bleeding and the lower hose was still cold. Time to pull everything apart again.
Pulled the thermostat housing off and boiled the thermostat. Guess what
It didn't open. I'll assume this was the cause of the radiator popping.
Luckily I had a new aluminium thermostat housing and lower temp thermostat, so replaced those and put it back together again (didn't take pictures).
This time bleeding the system was a breeze, took 15-20 minutes and it was done.
The car stays super cool now and so far, no issues or leaks!
Funnily enough a mate of mine had a leaky coolant bottle on his 328i (the car my Contour wheels have ended up on), so he ended up doing exactly what I did a few days later (alu rad, coolant hoses, VW coolant bottle etc etc) so we went for a little cruise to check that both cars were good and cooling systems were operating correctly. We've been having 35'C+ weather so if they were going to overheat or have issues, it would've happened.
Next up is the dual fuel pump setup I need to do before the next private trackday, so that'll be the next update.