I have a 79 F250 that overheats when I am at idle or in slow traffic. All the belts are tight, I have a 195 deg. thermostat installed properly, 50/50 coolant/water mixture, and fan shroud in place. I also have a manual temp gage. When I am going down the freeway, it reads somewhere between 210-230. Which is fine. When I am at idle, or slow traffic, it gets 230 -250+. I just replaced the Ported Vacuum Switch, and it doesn`t seem to help that much. The manual says that the hose from the EGR is supposed to be routed to the PVS, then to an EGR port on the carb. I only have 2 ports on this carb. A timed and non-timed one. Is there any where else that this vaccuum line can go and still work?

 

Living in Nevada, it wouldn't be a problem putting in a 180* thermostat.


[font color=red]Dennis
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How's the fuel/air ratio?

 

I would go with the 180 thermostat. If that doesn't work, you might check into some of the better water pumps available. Also, maybe a better fan.

 

Have you tried getting the radiator boiled out?? Maybe upgrade to a good 3 or 4 core radiatorr?? There are several products taht claim to lower the temp of the coolant, one I believe is called "Water Wetter". I have been told that high flow water pumps are not worth the hassle, and do not leave the coolant in the radiator long enough to exchange heat. I would avoid using one. (if ford thought they were so great they would have adapted to them) This is what I have heard though, so....

As far as the EGR and PVS' are concerned it should be hooked up as such. The ported vacuum gets teed off and goes to the Blue colored PVS(125* I think) and then to the EGR. The other end goes to the PVS that has manifold (full vacuum) on the top, to the dizzy in the middle, and ported on the bottom. The concept behind this is to kick up the RPM when the truck gets to a certaim temperature by providing full manifold vacuum advancing timing, and kicking up the revs to run the fan faster.

Tony

'77 F250, 4X4 460 transplantee, "Flamer"
'74 F250. 460, "beater" now "1 dead ford"
'73 F250, "midnight auto" now a trailer for the flamer

 

My 460 is overheating as well. I just flushed the rad out, and I am running a 160 degree thermostat. I mixed coolant to the max (70/30) for 136 degree boilover protection. Nothing is helping. Looks like a new rad? Idling is bad for it... Driving at 70 mph is about the only speed that keeps the temp from going over the range.
Does anyone know what is should cost to recore a 460 rad with 3 cores?
Mark

https://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=5362&.jpg
Ford started it; Ford will finish it!

 

Oh, and I have on it a 16 pound rad cap (Motorcraft)
Mark


https://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=5362&.jpg
Ford started it; Ford will finish it!

 

I have a 1979,f250,460v8,ac and it heats up to the mark on gauge just before the "hot" zone on the gauge. When I slow down from 60mph to about 40 mph it drops back to the center of the gauge. I was pulling a 24' 5th wheel,not sure on weight,and outside temp about 90*. Have extra trans. cooler along with the one going in to radiator.Is the trans [c6] heating up the engine? Trans. seems to work alright.Or is my fan clutch getting bad? Also trans. is about 1 qt. overfull. Will that make it run warmer? Thanks in advance jerry p

 

I should also add- 103,000miles and pretty much stock. What do you set timing on these? Seems like I read where it should be advance a little if all stock. jerry p

 

All,
An overheat at an idle indicates a different type of cooling problem.
1. The radiator could be weak but if that was the case you should see it at speed also. A missing fan shroud could contribute but, I've never seen a fan shroud make that much difference.
2. What creates more heat at an idle than at speed? The auto tranny. It slips while at a stop. This creates heat. Try putting your truck in neutral and see if the temp drops. Consider it.
3. Air/Fuel mixture is too lean. Try rejetting.
KingFisher

 

>All,
>An overheat at an idle indicates a different type of cooling
>problem.
>1. The radiator could be weak but if that was the case you
>should see it at speed also. A missing fan shroud could
>contribute but, I've never seen a fan shroud make that much
>difference.
>2. What creates more heat at an idle than at speed? The auto
>tranny. It slips while at a stop. This creates heat. Try
>putting your truck in neutral and see if the temp drops.
>Consider it.
>3. Air/Fuel mixture is too lean. Try rejetting.
>KingFisher
Why would engine cool down when dropping speed from 60mph to 40 mph or less than 40? Is there any good way to check fan clutch? You would think more speed would get more air thru the radiator.I tried shuting off ac,didn,t seem to make much difference.Maybe a bad thermostat? I need help!! Thanks Jerry P.

 

Jerry,
Your vehicle could be running lean. Try pumping the pedal as you drive. I know this is weird and its actually difficult to do without shifting gears. If you could add fuel to the sytem through the accelorator pump, you may see the temp drop. I bet this will work, if so, you'll need to do one of two things:
1. Rebuild carb and get it cleared out.
2. Rejet carb and enrichen fuel mixture.
My Way is the Highway,
KingFisher

 

i live in phoenix, it was 110* today, i`m with ya on the heat. here`s the setup i`m running on my 410 FE.
4 core with a shroud. flex fan, set just slightly into the shroud.this makes a huge difference. if you run a shroud and have the fan up against the radiator, you have a big piece of decorative plastic in the engine bay.185* thermostat, and an electric fan set to kick on at 185*. i can run all day at 185* until i hit traffic, but it never goes over 195 * which is not bad when your driving on the sun.
i lived in washington state for years and never had an issue with this until i got down here, but the fact is FE and 385 series motors that have been warmed over put out a huge amount of heat.
i dont know about the 385`s but FE`s are cold blooded, and run nice around 180-190, everything before or after that is choppy.(just my experience)
hope this helps.

 

I had a 410 FE in my last 74 F100, and it ran cool as a cucumber in 90 degree weather. But, the rad was in great shape compared to my obviously-plugged rad in my 460 right now. The 410 was an awesome motor, and had more bark off the line than my 460. (both stock, but 410 with low miles/rebuilt) The 410 only had a 2V carb, and the 460 a 4V
Mark


https://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=5362&.jpg
Ford started it; Ford will finish it!

 

[updated:LAST EDITED ON 15-Jul-02 AT 10:35 AM (EST)]I have a overheating problem also. It has been continous over the past 3 years. Like someone above stated, it will go back down to normal if I slow down to about 40 mph.

I have a E350 351 W and the temp gauge is fine in traffic, around town or crusing down the highway at 55 mph most of the time. When it's hot out though and I'm crusing 65 mph, after a while, it tends to get just past the very top mark (normal) on the gauge. If I slow down to 40 or 50 mph it'll go back down a little. Sometimes the needle on the gauge slams way over and I almost have to stop to get it to come back down. Usually I just slow down to 20 mph and it'll finally drop (and quickly)in a minute or so. Which made me think the thermostat was getting stuck and it probably is.

I've replaced the thermostat (160 degree), flushed the radiator numerous times, used a cleaner on it (which did help), have made sure I had a 50/50 mixture of coolerant, and added a coolerant reservoir (overflow tank) to it. The shop has checked the timing twice and has had it in a few times looking for the problem. I just recently took the thermostat out and have run it without one just to see if the coolerant was circulating good through the radiator. In the driveway with the radiator cap off, the engine running and the heater on I can see the coolerant circulating. (That's great because I thought it was the water pump.) I decided to leave the thermostat out and drive it some. After a while of driving it goes just past the halfway mark on the temp gauge, slightly lower on the gauge than with the thermostat in. But, I'll bet if I drive 65 mph in the heat it'll get right back to near the top of the gauge.

So, what do you think? New pump, radiator, any suggestions?