Please see below. These were my repairs by Toyota SService: 1. The engine was brought with high revs at iddle, no overheating and no other problems; 2. This happened after putting approx 20 l diesel in the fuel tank and driving it for approx 30kms; 3. Previously the car stayed park approx 8 months with very few fuel in the reservoir and only driven occasionally for 20kms at 2 weeks interval. 4. The injection pump has been rebuilt; 5. The timing was done correctly. 6. The engine is overheating and blows smoke, not particularly any color. - what is the current situation, Toyota report: AFTER REPLACING THE COOLANT AND FUEL FILTER AND ADDING FRESH DIESEL WE FOUND THE BUS STILL WAS OVER HEATING, THERE IS NO EVIDENCE OF A WATER LEAK, WE REMOVED THE THERMOSTATE FOR WATER FLOW BUT STILL OVERHEATS, WE HAVE COME TO THE CONCLUSION IT HAS MORE UNDERGOING ISSUES THEN JUST THE INJECTOR PUMP THAT WAS OVERHAULED TO CONTROL THE OVER REVVING. WE BELIEVE IT HAS A BLOCKAGE IN THE COOLANT SYSTEM OR AN INTERNAL ENGINE COOLANT LEAK. NO FURTHER ACTION OR CHARGES TAKEN. GUEST ADVISED HE WILL HAVE IT TOWED. Questions: 1. Any idea what happens? 2. Please advise possible causes that you can see for about what happened till now; 3. Any idea how can be diagnosed... just want to be sure the workshops don't take advantage of me... 4. What is a decent time and money cost wise diagnostic? Thank you A LOT for reading this and for replying.