The Ford Barn

rjlester · 08-19-2025, 08:41 PM

My 54 Meteor with the 255 Flathead (Canadian car, we got the flathead one more year) has a new Champion radiator, 180 thermostats, 15lb cap, new water pumps and otherwise completely stock. Engine runs like new, in normal driving it never gets hot.

It does get hot if you leave it idling for more than about 10 minutes. Had it happen two years ago at a construction site on the highway, it approached hot on the gauge, but once we got the green flag, it cooled down in about 1 minute, maybe less once driving.

From what I'm told this is normal behavior for the old flatheads.

Recently I was on a car cruise with my wife in the car. I warned her it was going to run hot, and I might have to run the heater sometimes. Well we ended up idling and barely moving for about 45 minutes! The gauge was in the hot zone the whole time. I was holding my foot on the gas to keep the idle speed up, and that would bring the needle just above the "hot" line on the gauge.

It never boiled over, didn't lose any antifreeze at all. I shut it off when we parked, opened the hood to let it cool, and two hours later when we left it fired up and has been running just fine since.

Has anyone built a shroud for the rad fan? I'm thinking when I get time next summer I would build one, I'm really curious as to if that would fix this issue. I really wish I had my infrared temp gun with me, because I don't really know what temp that engine was actually running at.

08-19-2025, 08:41 PM	#1
rjlester Senior Member Join Date: Aug 2022 Posts: 291	Running hot with extended idle time. My 54 Meteor with the 255 Flathead (Canadian car, we got the flathead one more year) has a new Champion radiator, 180 thermostats, 15lb cap, new water pumps and otherwise completely stock. Engine runs like new, in normal driving it never gets hot. It does get hot if you leave it idling for more than about 10 minutes. Had it happen two years ago at a construction site on the highway, it approached hot on the gauge, but once we got the green flag, it cooled down in about 1 minute, maybe less once driving. From what I'm told this is normal behavior for the old flatheads. Recently I was on a car cruise with my wife in the car. I warned her it was going to run hot, and I might have to run the heater sometimes. Well we ended up idling and barely moving for about 45 minutes! The gauge was in the hot zone the whole time. I was holding my foot on the gas to keep the idle speed up, and that would bring the needle just above the "hot" line on the gauge. It never boiled over, didn't lose any antifreeze at all. I shut it off when we parked, opened the hood to let it cool, and two hours later when we left it fired up and has been running just fine since. Has anyone built a shroud for the rad fan? I'm thinking when I get time next summer I would build one, I'm really curious as to if that would fix this issue. I really wish I had my infrared temp gun with me, because I don't really know what temp that engine was actually running at.