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Discussion Topic:
Getting warm at idle
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682bear |
09-19-2023 @ 11:48 AM
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Member
Posts: 27
Joined: May 2023
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The car is a '40 Fordor with a 59A engine... I can drive it anywhere... drive it as far as I want to, and the temperature guage stays centered as long as I'm moving... if I stop and let it idle for a few minutes, it doesn't take long to max the original guage. It is not 'overheating'... I've seen temperatures of 210-215 on the head, measured with a thermal imaging camera. At that temperature, I can remove the radiator cap... it never boils. Today I drained the old coolant and flushed it... just with water. It was surprisingly clean. I disconnected the upper hoses to check the thermostats... they were stamped "155". I reinstalled the thermostats, refilled with fresh antifreeze and distilled water, and added a bottle of Water Wetter. It is a lot better... the temperature still creeps up at idle, but it takes a good bit longer, so I've improved it, anyway. I know 180 degree thermostats are recommended... I'm planning to order a pair and replace the 155s, but I'm wondering how the 180s will affect the idle temperature issue... will it improve or get worse? Considering that it never seems to get above around 215 degrees, should I really even be concerned with it, anyway? Advice is appreciated... Thanks- Bear
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carcrazy |
09-19-2023 @ 12:41 PM
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Senior
Posts: 1653
Joined: Oct 2009
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If it were mine, I would stay with the cooler 160 degree F thermostats. Flatheads run warm enough without going to 180 degree F units. Why do you let the engine idle for so long? If you want the engine to cool properly at idle, you might want to consider using an electric cooling fan in place of the crankshaft driven mechanical fan. Once you eliminate the mechanical fan, you will probably have the space required to mount an electric cooling fan on the engine-side of the radiator. A 14" diameter fan is available and should provide ample cooling for your engine under all conditions when installed as a "puller" to pull the air through the radiator. Use metal mounting brackets that mount to the framework of the radiator rather than mounting to the core of the radiator. For maximum efficiency, mount the fan near the top of the radiator core where the hot water enters it. Aftermarket electric fans are available as either 6V or 12V. You can set it up with either a simple on/off electrical switch or a thermostatically controlled switch which senses engine temperature to turn on the fan. If they are functioning correctly, i.e. fully open at 180 degrees F and your idle temperature is above that range, the 180's shouldn't adversely raise your idle temperature.
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682bear |
09-19-2023 @ 1:02 PM
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Member
Posts: 27
Joined: May 2023
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I normally wouldn't let it idle long enough to get that hot... but there is always a chance of being stuck in a traffic jam, so I'd like to be prepared for that. I've seen the 6v electric fans... I'm wondering what the current draw is on those... I haven't spent any time researching them... I'm considering temporarily installing a pair of aftermarket temperature guages... one for each head... just so I can have quantifiable temperatures... instead of the 'low-middle-high' zones on the factory guage. Just from what I've seen using the thermal camera, the passenger side head typically runs around 8 degrees cooler than the drivers side head... the driver side thermostat opens at a hotter temperature. -Bear
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carcrazy |
09-19-2023 @ 3:19 PM
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Senior
Posts: 1653
Joined: Oct 2009
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One source for 6V electric cooling fans is Fifth Avenue, https://www.fifthaveinternetgarage.com/cooling_parts.php. They claim that the current draw of the fan motor is 4 to 6 amps. If you want to mount temperature gauges in an auxiliary gauge panel below the dash board, I recommend Stewart Warner mechanical gauges with the lighting kits so you can read them at night. If you haven't already done so, you can check the opening temperatures of your thermostats in a pan of water on the kitchen stove with a candy thermometer. If your car is equipped with a hot water heater, the temperature may be lower on the right side due to water being circulated through the plumbing and heater core.
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JayChicago |
09-21-2023 @ 8:03 PM
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Member
Posts: 480
Joined: Jan 2016
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Since overheating only occurs at idle, my thoughts went to the fan which is only needed at idle. Since this is a replacement engine, how far away from the radiator is the fan? More than an inch or so, air gets pulled in from around the perimeter of the fan rather than through the radiator fins.
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682bear |
09-22-2023 @ 12:14 PM
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Member
Posts: 27
Joined: May 2023
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The gap between the fan and radiator is roughly 3/4 inch... I'm not sure how to change that without putting a spacer between the fan and crankshaft... ?
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carcrazy |
09-22-2023 @ 1:17 PM
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Senior
Posts: 1653
Joined: Oct 2009
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One issue that makes 1939 Ford Deluxe, 1940 and 1941 Fords more difficult to cool is the location of the crankshaft mounted fan. It is near the bottom of the radiator. To maximize the effectiveness of the cooling system, you want the cooling fan to be as close to the top of the radiator core as possible. The hot water from the engine enters the radiator from the top and flows down through the core. Ideally you want the fan to conduct the heat out of the water when it is hottest.
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JayChicago |
09-23-2023 @ 10:23 AM
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Member
Posts: 480
Joined: Jan 2016
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Yes lower location of fan is not ideal, but it works, the hot water gets down there. My forty could idle all day long without raising the operating temperature too much. 3/4 inch space between fan and radiator is normal. That is good, not the problem, don't fix it. I would think the radiator is good or you would have overheating while driving, not just at idle. But you could try something easy: clean with Simple Green or similar product. Spray on the fins, then use garden hose from behind radiator to blow back against the way dirt gets forced into the fins. Also inspect the fins and straighten anything you can to help air flow thru the fins. My only other thought is perhaps the pumps are weak. Maybe old impellers are rounded over? Maybe good enough at higher RPMs but not moving enough water at idle? I'm grasping now because I'm out of ideas. I have no experience with pumps. Wonder if others think weak pumps are a thing.
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682bear |
09-25-2023 @ 2:17 PM
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Member
Posts: 27
Joined: May 2023
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Ok, thanks, I appreciate the information. I need to replace the lower hoses... so when I drain the system again to do that, I'll replace the pumps, also. I'll remove the radiator to make it easier to do the pumps, and thoroughly clean it while it's out. Does that sound like a good plan? Also, are the new pumps that Dennis Carpenter sells decent? Thanks! -Bear
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TomO |
09-26-2023 @ 6:35 PM
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Senior
Posts: 7250
Joined: Oct 2009
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I was disappointed with the Carpenter water pumps that I bought. The castings were very rough and did not look like the original pumps. I haven't seen the Drake pumps, so I can't comment on them. Skip Haney in Florida rebuilds the original pumps with improved impellers. They work very well. I Filling Speedway's pumps on my engine 20 years ago and they have worked well for me. While your radiator is out, you could try filling your block with Evaporust and then letting it sit in there a day or so. Flush the block from the outlets in the head. Some people have tried this and reported good results. You could also buy a couple of feet of 3/16" wire cable, chuck it in your drill and run it through the water passages to help loosen the junk in the bottom of the block before you use the Evaporust.
Tom
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