Overheats while idling ..
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New User
Joined: Jul 2009
Posts: 13
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From: Fontana, Ca
Overheats while idling ..
I replaced the radiator because it leaked, the water pump is new. I've replaced the thermostat and temp sensor (heck those things didn't even WORK when I got the truck). At least it's showing a temp now. The engine and trans were rebuilt just before I bought it.
I can drive this truck around all day in the So Cal heat without a problem. However if I go through a drive-thru ... it over heats - pretty quick, in fact.
I suggested the idea of the fan clutch to my Dad. He said that these Fords don't have fan clutches. I looked it up online and it offers two fan clutches for the 73' 390 .... I swear I see one one there.
So whats your thought on this?
I can drive this truck around all day in the So Cal heat without a problem. However if I go through a drive-thru ... it over heats - pretty quick, in fact.
I suggested the idea of the fan clutch to my Dad. He said that these Fords don't have fan clutches. I looked it up online and it offers two fan clutches for the 73' 390 .... I swear I see one one there.
So whats your thought on this?
Post Fiend
Joined: Jul 2006
Posts: 6,948
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The current fan is simply not drawing enough air through the radiator whan the vehicle is not moving. If you can cruise around and not overheat, then the radiator is fairly efficient, but once the aorflow stops as the vehicle does, you overheat, then the fan is either too small, too far away from the radiator, or not located within the shroud.
Perhaps the truck is not running a shroud, and this can be the problem. Many trucks without shrouds will overheat this way.
Perhaps the truck is not running a shroud, and this can be the problem. Many trucks without shrouds will overheat this way.
Junior User
Joined: Jun 2009
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Pressure test the system yet? Could be a wide variety of things that would be what I would check first instead of just replacing parts. Check for pressure leakdown, if you have none then you can troubleshoot from there. Adequate airflow could be another issue, alot of FE's tend to run hot at idle in the summer weather kinda like the modulars. An electric fan may be another option but try to do the free stuff like a pressure check before you start throwing money at it. Just my .02
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New User
Joined: Jul 2009
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From: Fontana, Ca
My brother pressure tested it. He said it was just fine.
The shroud is on but the bottom 1/3 of it is missing. I have a new one on order.
I looked at the fan and thought it was rather on the smallish side for a fan. Maybe I'm right. I'll try to get a photo today and post it.
The new radiator we put in bolted up a little funny. I didn't like the radiator, the auto parts people INSIST it's the right one. It's plastic. WTH with a plastic radiator?! It actually sits about 2 inches further from the fan. Will this make that much of a difference you think?
Right now I have the shroud off because we aren't driving it and I don't see putting the old one on and then having to take it off and put the new one on.
Photos will be forthcoming. Thanks for the input guys I appreciate it. I used to ask my grandad these questions because he was a mechanic but he's not around anymore.
The shroud is on but the bottom 1/3 of it is missing. I have a new one on order.
I looked at the fan and thought it was rather on the smallish side for a fan. Maybe I'm right. I'll try to get a photo today and post it.
The new radiator we put in bolted up a little funny. I didn't like the radiator, the auto parts people INSIST it's the right one. It's plastic. WTH with a plastic radiator?! It actually sits about 2 inches further from the fan. Will this make that much of a difference you think?
Right now I have the shroud off because we aren't driving it and I don't see putting the old one on and then having to take it off and put the new one on.
Photos will be forthcoming. Thanks for the input guys I appreciate it. I used to ask my grandad these questions because he was a mechanic but he's not around anymore.
Post Fiend
Joined: Jul 2006
Posts: 6,948
Likes: 44
Sorry about the grand dad. Lost mine not long ago, and it is unfortunate.
SOunds as though your shroud is the problem.
I have several large capacity radiators, (OEM) that are just waiting to go back into another truck, and I am right down the road from you. You are welcome to stop by the shop and take a look. If the truck can make the journey, we can take a look at your fan as well. Pretty sure I have some OEM fans laying around too.
I have a shop in Ontario, and Pomona, so I am just between the 10 freeway and the 60. Just a hop skip and a jump from you.
I may be in the Pomona shop today. Gotta get some work done on a couple of dana 60 front axles, and finsih up a roll cage, as well as get some sanding done on a 75 that is being painted.
Feel free to give me a yell...........
SOunds as though your shroud is the problem.
I have several large capacity radiators, (OEM) that are just waiting to go back into another truck, and I am right down the road from you. You are welcome to stop by the shop and take a look. If the truck can make the journey, we can take a look at your fan as well. Pretty sure I have some OEM fans laying around too.
I have a shop in Ontario, and Pomona, so I am just between the 10 freeway and the 60. Just a hop skip and a jump from you.
I may be in the Pomona shop today. Gotta get some work done on a couple of dana 60 front axles, and finsih up a roll cage, as well as get some sanding done on a 75 that is being painted.
Feel free to give me a yell...........
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New User
Joined: Jul 2009
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From: Fontana, Ca
I have a ton of plans that were made for me today otherwise I'd love to.
Perhaps sometime this week?
Perhaps sometime this week?
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Post Fiend
Joined: Jul 2006
Posts: 6,948
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Sure, I am always fumbling around one shop or another, so let me know. Anyone that knows me, or has been to my shop(s) knows that the offer is always open.
Find a way to share a private form of communication (not on a public forum) and I will give you an address or my personal contact info, and you can stop by. I'm actually headed to Fontana today (though I am out that way all of the time). I will be at the 10 freeway and Cherry this evening.
Its no problem though, just let me know........We can all share some stories about these old trucks, I own a few
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