Do you have a Patrol which tends to run warm when pushed very hard? I did- it was never a major problem, rather something I had to occasionally keep an eye on, (TD 42 with aftermarket turbo). I had the turbo reworked ("Power Up") which took the boost up to 12" and made a huge difference in power, but was a bit concerned about engine temp on a hot day....
Yet now- it's bloody fantastic- I hauled a 2.5 tonne van up Cunnunghams Gap the other day- 30 degrees plus, aircon working very hard, loaded car and van to the gunnels- and temp rose from normal position below 1/2 to just on half -no more. Oil temp got to only about 98 degrees celsius. (I have VDO gauges oil temp, oil pressure, turbo boost) Brilliant!
What have I done? A number of things which all compliment each other, but which I felt neccessary as I knew I'm working the engine hard, and didn't want to risk overheating it.
1. Viscous fan is now working as it should, with new silicone and a slightly modified (bent) bi-metallic spring. It cuts in when it should- this fan is probably the biggest cause of people's overheat problems.
2.New HIGH FLOW thermostat. (old one was standard)
3.Radiator has been flushed and refilled with only about 30% glycol (did you know the higher percentage glycol you use the hotter it'll all run) AND Redline's "
Water Wetter"- thought I'd give it a go despite the expense($27) and I'm pretty impressed- although I can't prove anything as I did a few things at once.
4.Bypass oil filter which feeds through a transmission style oil cooler thus feeding cool oil back to the sump (which I've had for some time- it probably adds a bit over a litre to total sump capacity)
5.I used a Commodore heater valve to allow
water thru the heater pipes without going thru the main heater core- this
water then goes thru another heater core behind the bull-bar- total cost for the above mod about $60 (new commodore heater valve $27, plus heater hose, and a heater core from the wreckers.
Radiator is ORIGINAL (old like me) , with quite a bit of external corrosion on the lower fins (many at the bottom are gone completely). Wow- what'll it be like when I am eventually forced to recore it?
I don't know what I'd have to do to overheat it now- I reckon it's bullet proof and I'm very happy.