86 Overheating
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Joined: Feb 2003
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86 Overheating
I flushed radar, and replaced all hoses and thermostat. Truck kept overheating. I suspected that maybe I got a bad new thermostat, so I replaced thermostat again. Truck still kept overheating. Again I thought maybe just bad luck and got a bad thermostat. Spent a little more money and purchased a Robertshaw thermostat. Truck still kept overheating. I purchased a new heavy duty 4 pass radaitor thinking maybe my original was just all scaled up. Truck does not overheat while your driving anymore, but now overheats and boils completely over after you turn engine off. Any ideas, I'm lost.
Fleet Mechanic
Joined: Nov 2003
Posts: 1,372
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From: West Cornwall, CT
Your truck will heat up some when it is turned off, but if the radiator cap is in good shape very little coolant will overflow to the overflow bottle.
The radiator cap is easy to check and to replace and I'd look at it first. If the cap is OK, then the engine probably is running too hot. I had this problem with an '83 F-150 and it ended up replacing the water pump after everything else. The cap, and as beast12 mentioned, the thermostat and shroud definitely need to be double checked before replacing anything else!
Lou Braun
The radiator cap is easy to check and to replace and I'd look at it first. If the cap is OK, then the engine probably is running too hot. I had this problem with an '83 F-150 and it ended up replacing the water pump after everything else. The cap, and as beast12 mentioned, the thermostat and shroud definitely need to be double checked before replacing anything else!
Lou Braun
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The shroud is in place, and in good condition, and cap appears to be working under normal test conditions. I've even removed the thermostat and drove the truck. The truck runs normal as long as your moving, but if you stop at a light with the A/C running it starts to inch its way up. When you stop and turn engine off within about two minutes it boils over the overflow. I'll try the radiator cap it may be failing at times.
Hotshot
Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
the problem with totally removing the thermostqt is that there is no restriction to flow, so the coolant doesn't stay in the radiator long enough to effectively cool. Eventually the whole system of coolant gets hotter, and won't cool when slower. If you want to really try it that way, take the center out of the old thermostat and run it that way, it is then a restrictor plate for the cooling system, and will help.
Post Fiend
Joined: Mar 2003
Posts: 14,413
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From: Sarnia, Ontario, CANADA!
Hmmm...suspecting fan clutch.......may want to replace. If you do a search there is a way to "test" it but I am not 100% sure how. Good luck!
-Matt
EDIT: Here is a link that may intrest you: https://www.ford-trucks.com/forums/s...ht=fan+clutch+
-Matt
EDIT: Here is a link that may intrest you: https://www.ford-trucks.com/forums/s...ht=fan+clutch+
Last edited by Beast12; Jul 21, 2004 at 03:16 PM.
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I would suspect the water pump. Have you watched for flow with the rad. cap off when it is first started? I say it that way to mean that the cap should never be removed when hot. I had the same problem. Did the same as you; turned out to be a bad pump.
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Laughing Gas
Joined: Apr 2003
Posts: 837
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From: Minnesota
Originally Posted by thpdpstxcity
I flushed radar, and replaced all hoses and thermostat. Truck kept overheating. I suspected that maybe I got a bad new thermostat, so I replaced thermostat again. Truck still kept overheating. Again I thought maybe just bad luck and got a bad thermostat. Spent a little more money and purchased a Robertshaw thermostat. Truck still kept overheating. I purchased a new heavy duty 4 pass radaitor thinking maybe my original was just all scaled up.
In the process of replacing my OEM trailer tow package three core with a new four core "Heat Buster" I discovered that my old one was seriously plugged up behind the ac condensor with bugs, dirt, etc. Even the radiator shop I had look at it missed it. I put in the new one ... silly not to ... and it took care of the problem.
I don't have a sure cure for what you've got going but as fellro86 posted earlier cooling isn't quite as simple as it seems. Here's a link that I learned a lot from:
http://www.grapeaperacing.com/GrapeA...ingsystems.pdf
Roger
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Tuned
Joined: May 2003
Posts: 345
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From: Southern IL
My 83 does the same thing if I'm stopped or pulling up hill. I strongly suspect the transmission is at least part to blame. If it is overheating, it will cause your entire system to run "hot". Also, if you fill your radiator completely full and you don't have a recovery system, it will overflow when you shut it off until it gets down to about "1" inch below the top. I have set the idle up on my rig just a bit and that has helped some.
83 F250HD 4x4 460
83 F250HD 4x4 460
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New User
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Thanks for all the advice. I totally forgot about the fan clutch as a possible factor. I have replaced the radaitor cap. My overdriver trans is brand new. Truck has not overheated since new radaitor cap, but if it does act up anymore I have alot more ideas. Thanks again everyone.
Mountain Pass
Joined: Jan 2002
Posts: 198
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From: Ft. Pierce Fl usa
Been through this three times now and always forget the fan clutch. No good way to test it. I have a life time warrenty on the fan clutch and each time I take it back they tell my nothing is wrong with mine. I put the new one on and it works great for a year or two, then it starts again. Next time I will remove the clutch and put the straight spacer in, at 8.5 mpg the fuel savings won't be seen, and no more mystery every other year.
MT
MT
Senior User
Joined: Jul 2003
Posts: 114
Likes: 1
From: Tyrone GA
By any chance, are you getting the fan clutches made by hayden? You get these from all the major auto parts stores. Plain and simple, they are unadultered garbage. The best fan clutches are actually the stock OEM ones from ford. They work great. This was discussed on another forum i'm part of, ProjectBronco, heres the link. http://www.broncotech.com/cgi-bin/ul...c;f=5;t=002487
Look for what Paul E has to say on the clutches. Hope this helps you.
Look for what Paul E has to say on the clutches. Hope this helps you.
Last edited by alcan60283; Jul 25, 2004 at 09:30 PM.
Freshman User
Joined: Jun 2004
Posts: 49
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From: SOUTH WEST FLORIDA
i just spent over $500 on my 86 f250 4x4 with this same problem. my problem was the gage was bad. my suggestion is to make sure it is really running hot. invest in a decent temperture gage and see if you really have a problem. i didn't and installed a new radiator, thermo, etc etc. as i understand bad gages is not unusual on these models.
amazing what a new gage will do!
amazing what a new gage will do!
Posting Legend
Joined: Sep 2001
Posts: 30,255
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When the engine runs cool at road speed and hot in traffic or stopped always suspect the fan system. Above 30-40 mph your vehicle pushes air thru the radiator. Below 30-40 mph the fan pulls air thru the radiator. If you have a stock fan, suspect a missing radiator fan shroud or the clutch. The fan is a system, the fan, clutch unit and shroud must all be working. A plugged up radiator either internally or externally will usually show at any speed.
SAWDUST, did you try a new sending unit?
SAWDUST, did you try a new sending unit?