Engine radiator Koyo or OEM Volkswagen

EDIT: SOLVED - noticed no leakage around thermostat, coolant ball, all belts were dry, and upper radiator dry. In the end it was the radiator.

run a mk4 secondary rad.

I will will just add that I have a 2L 16V running no oil cooler and an early Mk1 radiator with built-in overflow tank, two pin thermostat, short 5th gear, and the car does fine in a traffic jam and with spirited driving.

90 16v Passat rad fit just fine in my mk1 Jetta with a single fan mk1 (which mounted to the rad just fine) you can cut the wires and set them up for how ever you like.

Koyo is what I'm using. Quality stuff. I'd highly recommend.

Regarding our 1997 Jetta GLS that we've had since it was brand-new, I was topping off the original G11 with G12+ since about 2000, without any problems. A few years ago we had the radiator replaced, and the coolant was all changed out to G12 -- that is, the current G12.

I replaced the coolant tank, blue resevoir cap, thermostat, water pump and coolant but didn't help. Problem was my radiator was partially blocked. I replaced my radiator this spring and it's run like a champ.

VR6 Passat *works for an A3 radiator but will need modifications