The original engine in my 53 XK 120 DHC has been rebuilt with a new water pump & 6-blade fan, plus a new radiator, but still overheats at idle. It is fine as long as the car is moving at even low speed, but the temperature begins to climb as soon as the car comes to a stop. I would prefer not to go to an electric fan and understand there is a higher capacity plastic fan available that might provide the extra air flow needed. Can anyone provide more information about fan blade options for this car and where a higher capacity fan can be purchased. The car is a left hand drive, chassis #677076, engine #W8291-8.
Submitted by SW03-09811 on Mon, 09/01/2014 - 16:04
Gary,
You didn't mention your thermostat.
You would do well to verify that you have a proper thermostat with a collar that blocks the by-pass when the engine is warm. If it is not an original-style thermostat, I suggest blocking off the by-pass hose completely and drilling an 1/8" hole in the existing thermostat valve plate. (This allows some warm-up circulation but assures that all the coolant passes through the radiator.)
Also check that your water pump doesn't have an over-sized pulley.
If none of that is applicable, you should also take the larger step of inspecting the water pump cavity in the timing chain cover. The efficiency of the pump is very dependent on the condition of the (cast alloy/aluminum) water guide that surrounds the pump impeller. If it is badly chewed up, it should be repaired of the cover replaced.
Electric fans are almost mandatory for any "warm climate" stop and go driving or freeway driving followed by stops for only a few minutes. The fans can be installed for easy removal and can take a lot of stress out of a casual 120 outing.
If you want to try a couple more blades, I have a nice fan from a 140 that is trimmed down to fit a 120. email me direct.
Good luck,
Dick Cavicke