I decided on Saturday morning to do some detective investigation.... CSI Maimi.... meets CSI LA ( Lower Alberton - which is a town just south of Joburg )....
Why was the Patrol all of a sudden getting hot? That small leak on the top radiator hose surprised me that it could be the cause, as the hose is still very "soft" and plyable, and not hard or cracked. The coolant water is crystal clear , but a dark shad of blue from the coolant mix ( no rust or contaminants ). The water pump cannot just all of sudden not work. If that was the problem there would be a slow progression from not overheating to overheating, not a sudden now it works, and now it doesn't. The thermostat is working perfectly and still looks brand new. There is no airlock in the system as it would have air in the radiator when I check it when cold. Its not the cylinder head, as I would see bubbles when its hot through the radiator.
Now the viscous fan is 2 years and 2 months old. I bought it from the guys in Cape Town that many of us have bought from ( I cannot recall their name, but will have to search in a few mins to get their number to order another one ). So while the motor was hot I listened to the fan and it didn't sound like it was locked or even semi locked, so I took a piece of rubber pipe to see how "locked up" the fan was. I was gobsmacked that I could stop that fan with hardly any effort at all. I switched the car off and memorized roughly how tight the fan was to spin.
Once the car was cold the fan took the same amount of effort to spin, so I think now that the viscous fan has konked out, which caused the overheating which caused higher pressure ( radiator cap is a 0.9 bar cap if I recall ) which caused a slight leak on the hose.
Now to get a new viscous .... and quickly !!
So Brett you were bang on the mark. My aircon fan bearing was making horrible noises a year or so back so I disconnected it as many Patrols here in South Africa don't seem to even have then fitted. I never really had any issues with the fan not operating so was never in a rush to change it. Michael on the forum offered me his old aircon fan a few months ago so I swapped it out this weekend too whilst all the investigation work was taking place.
So .... CSI LA investigation report..... Even a "new viscous" fan that has only done maybe 35 000Km can die on you.
When I took the viscous out this was the first thing that caught me eye.... That "spring" heat thermostat thingy shouldn't look like that!!! The end of the " spring isn't even attached to the center spindle!!