Yesterday I was in a long line for about 30 minutes, engine idling, intermittently creeping forward. Temp gauge edged up slowly until it was well out of the "normal" range, maybe a needle-width away from "H." The ambient temperature was around 78-80 F. The temp gauge needle never settled at a point, and it may well have kept climbing if the line were longer.
I don't know if this is an overheating "problem," but I'd like comment on it.

The engine has 70,000 miles and a new water pump & a new 3-row Modine radiator with new 13-lb. cap. Radiator hoses are new. The radiator seller gave me a new thermostat, which I believe is a 180. The engine has Pertronix ignition, with Autolite 45 plugs gapped at .044. The timing is set at 6^ BTDC, Total Advance 43^BTDC @ 3300 rpm.

The belts are correctly tensioned. The original 4-blade fan has been replaced with a Ford 5-blade fan from a big old station wagon. I have not yet checked the coolant-water ratio. The oil is fresh 10w-30.

Running on the highway at 60 mph, the temp gauge runs a little above the mid-point of the "normal" range. The gauge is original in its Custom Cab dash.

Thanks for any comment.

 

Lil bro, Our ol trucks are bad for that. Ford stuck a big ol radiator in there and as long as you are moving, no problems. Our trucks were not designed to be in traffic.

Some fellers like the electric fans, others fan shrouds and newer flex fans. You cannot see the radiator on my Taurus but it will idle in 98º heat for hours and the temp gauge not move.

You need to inprove air flow at low movement speeds like you refer to. You can always rev the engine and that seems to help. Look at a newer truck for ideas on how to direct the air flow.

hope this helps a little

John

 

This part matches my experience, when it is working correctly.
I'd agree that the higher temp you experienced is not good. I had a bad thermostat that caused me no end of headache until I figured it out, and that is the only time I saw the needle go as high as you described. My setup is nearly exactly like yours, so I can't offer any other suggestion other than you have a flow problem (water or air) at a near idle. Seems like you're doing everything right.

 

Wow, this is news to me! My '65 352 is all original and has NEVER had any overheating whatsoever. I've towed some serious loads in the 100+ Texas heat and the gage barely moves from the 180 mark(or an approximation thereof). I'm running a 180 deg t/s, 50/50 mix, original fan and radiator. I always thought that with as much coolant as this things holds it could never overheat!

 

Paul, I don't disagree with anything that you posted. I think if you will have it up to operating temp. and pull into a parking lot and let it idle for a few min. you will see the gauge start moving up.

It is air flow or the lack of that causes this. The newer vehicles do a much better job of directing air through the radiator.

Two things I can not do with my truck, let it idle in the heat for a period of time, and park it drivers side down with a full tank of gas.

John

 

Find a fan shroud for your truck if you sit in trafic alot. Shrouds will increase the eficanciy of the fan.

44

 

I guess what I am saying is that I agree the temp will increase slightly at idle after it is warmed-up (heatsoaked). But will will not "overheat". I regularly tow a 6500 lb. 5th wheel camper. After and hour or so of 65-70 MPH interstate driving I'll pull off....to re-fuel! (4bbl, 4:56 gears) If it were to "overheat" it would be then. My needle normally points to just under the "N" in "Normal", and has never gone past the "O". I do have a shroud but have never installed it. I'm building a 390 for it and plan on using the shroud and a fan w/ clutch as it will then also be running A/C. Hopefully that wont be an issue.
I don't know how many of you are actually running the original radiator, but I am. Do you 'spose that makes any differance? It is a 3 row'er and the radiator shop said they don't build them as heavy as that anymore. Don't know if that is better or worse.

 

Did you have a cooling issue before installing the Pentronix ign. Have stock cooling sys. and remains constant at 180 in all type driving conditions. Installed Duraspark ign. in 65 with 390 and found needed to advance few degrees. The 390 is bored .060 over so may explain. Believe dwell decreased 4 to 5 degrees with the upgrade. Not that knowledgeable about the subject just found engine ran better with the change in setting.

 

I do have a fan shroud on my 65 352, but the fan is the 4 blade orginal with no clutch. My gauge runs just into the normal range even with the air on in 110 degree heat here in Az. The previous owner did replace the rad about 10 years ago, but it's not over-sized or anything. No problems on this one.

Must be the shroud doing it's job.

Keith

 

Paul, I'm gonna have to keep my eye on you boy, your engine may not have overheated yet, but you aint going far into that or so hour before needing a fuel stop with that gear ratio setup.

Do you race your truck?

John

 

Last June, Austin to TMS for the truck race(NASCAR), 204 miles one way, towing the camper, and stopped once for gas. On the way home it was at least a billion degrees (No A/C remember, YET), no problems.
4:56 gears are really not as bad as most think, yes it runs 3500 RPM on the highway for hours at a time, and most feel that is way too high, but it really doesn't effect MPG like most believe, especially when you're towing, as mine does most the time. With that big camper I get 6.5 - 7MPG. Now the flip side is that I get 6.5 - 7 MPH with out the camper!
No, I don't race it, I would be smoked, you cannot get a pickup with one very hard "E" rated tire to hookup with the 4:56! Would probably run a 17 sec. 1/4 mile(and use 2 gals).

 

Paul, Why are flogging that ol horse so bad? When I had the 2.75 rear in my truck I could use all of the numbers on the speedo at 3800 rpms. I have a 352 with roughly 21,000 miles on it and recently changed to a 3.00 rear ratio and got better pulling. The last trip that I made was to Charleston SC pulling my 18ft car hauler I got 13.9 (best tank) while maintaining 70 mph on the flat land. When I loaded the 92 F150 supercab on and headed back I still was in the 10.5 range, still maintaining 70 mph.

When you are turning an engine that hard you are wearing it out earlier, and buying a lot more gas.

What engine are you running anyways a 240?

John

 

Hey John, it's built "Ford Tough"! It's a 352 with 113,000 miles and bone stock except for Duraspark and a Holley 4bbl. I am in the middle of a 390 build and would love to go to a more reasonable rear gear, like a 3:73? However, finding a Dana 60 with the 3:73 is a little difficult, there's ton's of 4:10's out there.

 

Thanks to all who suggested air flow solutions. Standing over the engine compartment contemplating whether a fan shroud was needed, it occurred to me....

Of course!! The replacement 5-blade fan from the salvage yard came off a north-facing hulk. Since my carport faces south, I must've absent-mindedly forgot to turn my truck around before installing the fan.

Shows what can happen when a person ignores Feng Shui in the garage.

Expect no follow-up temperature reports.

 

Lil bro, I was purchasing rear axle seals and putting them in the wrong side of the truck, glad to hear that ya got it turned around.

Paul I know they are tuff, but you have your engine turning too high for it's power band. You can find gears a lot lower for the 60 than you are using. A 3.50 gear range will still make your trunk pull good and use a lot less gas. Your truck ought to pull a train with the present gearing.

John