August 23rd - Checking Cooling System On the trip back from Fishburn Airfield on the second day, shortly after setting off and about a mile down the road, I got a cloud of smoke/steam from under the dash lasting two to three seconds. I immediately pulled over and switched off. I noticed that the indicators had stopped working, so was it electrical? I opened the hood and then found coolant had been sprayed around the inside of the hood. It seemed most likely the coolant was the cause of the steam. The indicator failure I think was just a coincidence. I don't think the coolant got into the flasher unit. The engine had been running ok, so didn't think the cylinder head had failed. The engine turned over freely without any signs of water in the cylinders, so I took a chance and started it up again and monitored the temperature. It ran ok and the temperature was normal, despite loosing some coolant. I got home ok, though a little more slowly to be cautious. It took a litre of coolant to top up the radiator again. The following morning, the level hadn't changed. I was going on holiday for a week, so left the Jeep standing. When I got home, the radiator level was still where I left it. If there had been a problem with the head gasket, I would have expected the level to have dropped. So today, I decided to do a test to see if the thermostat was opening. I started the Jeep up and using an infra-red thermometer, monitored the cylinder head temperature, radiator top tube from the thermostat, the side and top of the radiator. See the pictures and table below.

The table shows the cylinder head temperature rising, then the thermostat opening and allowing hot coolant through the top tube into the radiator. The radiator temperature then starts to rise as expected. All the temperatures stabilised, there were no signs of leaks and no pressure release from the radiator cap or overflow pipe. The cylinder head temperature on the hand held monitor also matched the gauge inside the Jeep. Out of interest, I also checked the oil filter housing temperature a few times.
All seemed well with the test with the Jeep behaving as expected. It was put away for a while, as I had a steel 'I' beam to bring over from the old house as well as a few other last remaining items. Early evening, I got the Jeep back out and went for an eight and a half mile test drive to get some fuel and to see how it behaved on the road under load. There were a few gentle hills along the route and the speeds were varied. After filling up with fuel, I headed back to what I now call sun set lane, visited a few times with the Jeeps, stopping to check the temperatures with the hand held sensor again. As before, everything was normal.

I took a few photos after the temperature check, then headed home, clocking up 16,666.6 miles on the way. Another temperature check was done once home and all was still as it should be with the radiator level unchanged and no signs of leaks. There appeared to be no signs of coolant contamination in the oil and the engine was running smoothly, again suggesting the head gasket was ok. I plan to do some more tests before Beamish.

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August 27th - Indicator Flasher Unit Replacement At the same time as the coolant problem coming home from Fishburn, I noticed the indicators stopped working. This may have been coincidental, from moisture damage from the coolant, because the unit wasn't designed for LED lights or just because it is old. There was nothing obviously wrong when opened up, but a replacement, LED compatible flasher unit was fitted. The old unit used to flash quickly unless the trailer was connected, but the new one gives a steady flash with or without the trailer.