June 9, 2019, Ottawa, Canada, 30C(86F) outside. Wanna-be mechanic here. I have my Dads '68 4/4 a long way from home.
Unfortunately I happily drove 400km with the thermostat reading 70C --- the ambient temp outside was only 5C but eventually suspicious I checked the coolant to find that the reservoir was empty. I hadn't checked it before I embarked on this trek (sorry everyone) - topped it up for the last leg of the drive, into the city, and now the temp gauge is reading 110C. I reached my destination, checked that coolant was at the top of the radiator cap and then I noticed a pin hole leak at the top of the rad (in the top reservoir part).
The aluminum Marston Excelsior radiator had sprung a pinhole leak before or after I stated the trek and (coincidentally?) the engine is now overheating into the ~110-115(230-240F) degree Celsius range (according to the temp gauge and an infrared thermometer on the top of the rad). I can fix the leak but in the meantime I want to diagnose the overheating. I don't think the pinhole leak in the rad is my problem (or is it?).
The water pump visually looks good. No leaking.
I removed the thermostat for the second test run and also tested it to find that that it operated normally in a test bath.
I've removed (to find the hole), flushed and refilled the rad, and am not losing enough coolant from the pin hole in the 30minute test-run time, to get up to temperature, to need or be able to top it up.
First test: after I flushed and refilled the rad with deionized water, I let it idle for 20 minutes (maybe not long enough) and it peaked at 90C. Seemed good enough for a test drive.
Second test: Driving through downtown up to Rideau Hall, 40 minutes, 30C ambient temperature, thermometer goes up to 90C then after 30 minutes-from-cold, up to 110C, back to 100C... I put the heater on when the thermometer got to 100C.
I'm going to seek professional help now but would like to hear if anyone has any ideas.
Thanks,
Brad
'68 4/4
Engine: V-Comp, 116E GT, Ford Cortina
Radiator: Marston Excelsior
Water pump: Lucas 22716N
Last edited by BradB; 09/06/19 11:47 PM.
