astr

I've checked the oil, drained and refilled, and no contamination of the oil. I am inclined to attribute the coolant loss to a poor job of bypassing the turbo as the coolant loss only began after the turbo was bypassed. Unfortunately, I'm...

At this point, the oil cooler and oil cooler cover have been replace, the head resurfaces and a new Toyota head gasket installed and the turbo coolant lines have been bypassed. Made several round trips to town (1 hour each way) and a 100 mile...

The coolant lines have been bypassed. I'm not too worried about running without coolant to the turbo as turbos ran for years without coolant. Wherever the leak is, it it very small as it took several days of driving before any oil was evident...

Hi Dougal. I believe that the machine shop pressure tested the oil passages in the head to see if any air leaked into the coolant passages but anything is possible. The Prado is back at the shop and I will wait till they respond. I've passed...

Good idea. For many years turbos ran with only oil so that might work.

Manual transmission so no oil cooler in the radiator. I was also thinking turbocharger as it has high pressure oil and coolant running to it. How to verify without replacing it?

Update: Both the oil cooler cover and the oil cooler plate heat exchanger were replaced. The head was removed, gasket surface was resurfaced and the head tested for leaks - none found. All new gaskets were used including genuine Toyota head...