Running very hot
Posted by Jim Kavanagh On 2018/9/8 19:39:41
I just finished replacing my hydralic lifters on my 52 250. During the project, in addition to replacing the lifters (which required pulling and replacing the head), I replaced the water pump (the old one showed some leakage around the weep hole), rebuilt the carb, R&R the heat riser assembly, and replaced the heater control valve at the firewall. I did not replace the thermostat - had a new one, just forgot 
I pulled the radiator but did not have it serviced, i did a simply flow test and it emptied quickly. I did repaint it with radiator paint, just the top, not the fins.
Since reassembly, the car has run hot. I have dialed in the carb (which still runs just a little rich) and the timing, and that has helped. The car never ran hot before.
I live by the ocean, and the temp stays around 70 - 75 degrees, so overheating really should not be an issue.
Now, it will idle in my garage forever with no problem, but after about 15 minutes on the road, basically on the highway at 55 mph, the gauge slowly creeps over toward hot. I haven't run it long enough to get it there, but I am pretty sure it will go fully to hot with a little more time. My hand held laser thermometer shows about 210 degrees across the heads at that point, a little lower in the main block and the radiator at about 180. Previously, I never saw the gauge get above the center. In the garage at idle, even idling for a long period, it only gets to about 170 at the block, the radiator only about 140.
I did not flush or back flush the engine.
The water passages in the head were very clean.
I think my next step is to replace the T-stat, or maybe run without one for a while and see if that helps. If not, I'll run something through the system and backflush it - which is another reason I might leave the T-stat out for a while.
I am wondering if the pump could be under-performing. Is there any way to test for this? As a last resort, I can put the old one back on and see if that solves the problem.
I am running with the heater closed, but I don't think this should make any real difference.
I don't really want to tear into this again, so any thoughts would be appreciated.
I pulled the radiator but did not have it serviced, i did a simply flow test and it emptied quickly. I did repaint it with radiator paint, just the top, not the fins.Since reassembly, the car has run hot. I have dialed in the carb (which still runs just a little rich) and the timing, and that has helped. The car never ran hot before.
I live by the ocean, and the temp stays around 70 - 75 degrees, so overheating really should not be an issue.
Now, it will idle in my garage forever with no problem, but after about 15 minutes on the road, basically on the highway at 55 mph, the gauge slowly creeps over toward hot. I haven't run it long enough to get it there, but I am pretty sure it will go fully to hot with a little more time. My hand held laser thermometer shows about 210 degrees across the heads at that point, a little lower in the main block and the radiator at about 180. Previously, I never saw the gauge get above the center. In the garage at idle, even idling for a long period, it only gets to about 170 at the block, the radiator only about 140.
I did not flush or back flush the engine.
The water passages in the head were very clean.
I think my next step is to replace the T-stat, or maybe run without one for a while and see if that helps. If not, I'll run something through the system and backflush it - which is another reason I might leave the T-stat out for a while.
I am wondering if the pump could be under-performing. Is there any way to test for this? As a last resort, I can put the old one back on and see if that solves the problem.
I am running with the heater closed, but I don't think this should make any real difference.
I don't really want to tear into this again, so any thoughts would be appreciated.
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