I live in the US and have a 2000 Td5 110 CSW with Allisport re-chip, Allisport intercooler, EGR bypass and turbo boost box and stock radiator. Engine has 75,000 on it.
Was going up a steep grade at about 70 miles in 95 F degree weather and noticed the needle almost to red. Eased off the pedal and temp went back to normal. I could control the needle by easing off the throttle and slowing to 55 mph. Replaced thermostat, viscous fan, expansion tank, all hoses and flushed the system.
Did another test today in the same weather conditions and the problem persists exactly the same. This time I used a Nanocom to monitor the temperature. In 95 F degree weather in city traffic, coolant temp stays between 92 C and 98 C. On the freeway going up the steep grade I hit 117 C and the needle was almost to red. Stopped and checked under the bonnet and coolant wasn't boiling. Had a slight smell of coolant in the engine bay.
Noticed that the temp gauge will stay below the half mark from 80 C to 115C. After 115C it goes up rapidly.
Am I risking damage above 115C? I probably hit 118 C or 119 C the first time around. Do you guys think I caused any damage? What's the highest it can go without causing problems.
I'm not loosing coolant and my hoses are all soft. Don't think it is head gasket. Any suggestions?
By the way, 110 wasn't loaded and I wasn't towing.
Any help would be greatly appreciated.