We've had a bit of a heat wave up here in the Pacific NW and my truck has not reacted well.

The truck is a 84 F350 4x4 crew cab with a 460 and a C6, 4.10 gears, susp lift, running 35's. Factory exhaust manifolds, and a open element air cleaner on a Edlebrock carb. Coolant flushed and system pressure checked.

My issue: My temp gauge normally runs at about the approximate 1/4 to 1/3 area when running down the road, whether the truck is loaded or not. When stopped in traffic, it will creep up the 1/2 position, but it has never gone above the 1/2 position. However when I sit in traffic for an extended period and the temp gauge moves to the middle position, my idle drops, gets lumpy and acts like the engine wants to die. I end up driving with both feet to keep the rig from shutting off which is a PITA in certain situations. The underhood temps get HOT and I'm curious if that is the cause of my problem.

I have read in places that the 460 generates some serious heat. I've not learned a bunch about engines yet, so I'm looking for some help. Was told I may be experiencing vapor lock or something similar? Or is the engine starving for air since the open element air cleaner is sucking in very hot air (maybe some type of cold air duct would help)? Since the temp guage holds steady and doesn't seem to overheat (and my system pressure checked okay with fresh coolant, and my overflow works), I'm wondering if I need to do something to get rid of the hot air underhood? It got hot enough last weekend while sitting in traffic with the boat hooked up to the truck that the plastic ring that holds the aircleaner off the carb started to deform (melt) a little bit.

Any help appreciated.

 

You could try header wrap. I had a Toyota 4runner that it did wonders for in cooling down the under hood temp

 

Yup, 460's make some serious heat. Coolant jugs stored under the hood do some shape shifting.

Ford did a recall "way back when" that involved installing some heat reflective/insulating wraps on the fuel lines running to and from the carb (search: "Hot Fuel Option") to eliminate/reduce vapor lock. Mine are wrapped but still have had some problems. When the fuel in the lines gets hot enough it starts to go to vapor and that leads to problems delivering fuel to the carb. You might want to check that out further.

I'm sure that wrapping the headers would help. I've also been told that going to a 3" exhaust will lower temps by reducing back pressure.

I get so much heat under the truck when towing at high ambient temps that I have to run the front tank out first ... if I don't by the time I run through the rear fuel the front is so hot it will boil on the bottom of the tank and the fuel pump sucks vapor. This has happened frequently if I forget to switch back to the front when I refuel. It has taken as long as 20-30 minutes to get running again. I now make a point of switching back to the front tank when I'm refilling the front tank.

Floor temps when towing were always in excess of 100* before I installed the floor vents from a non-AC truck. The wife's side, right above the Y-pipe, has three layers of carpet samples. The floor vents dropped the temp 20+*. Insulating the floor is an upcoming project.

Below is a picture of Clyde's chrome exhaust tip. It's 4" x 18" and "heat blued" almost to the outlet. Took some serious exhaust temps to do that considering how far it is from the engine!!

 

Thanks to you both for the posts.

Couple more questions. Can I use header wrap on the factory manifolds (I don't have tube headers)?
I'll look into the hot fuel search and see what I can dig up also.

Has anyone tried louvers or scoops to extract the head from underhood?

Yesterday, with camper on truck and boat in tow, we spit coolant all over the drivers side front tire when I got home and parked all the gear. That sitting in one place w/o enough air flow through the radiator got it too hot and dumped a bunch of coolant into the overflow tank, which then overflowed itself onto my tire. Do I need a better/bigger radiator or new fan or aux elect fans?

I got lucky and hit no traffic on the way home yesterday so I didn't get stuck in stop and go traffic, but if I had, I'm 100% certain I would've had to stop and let things cool to get home based on what happened while I parked the rigs.

 

Have you checked your fan clutch? No electric fan will outperform the OE fan when it is operating properly.

Running hot on a vacation trip my OE radiator with ~58K miles on it was checked internally by a radiator outfit in CO, he found nothing wrong and recommended I go to a cooler thermostat ... which I did to no avail. When I returned home, totally disgusted with the whole situation, I ordered a new 4-core TransPro HeatbusteR radiator. As I was lifting the old one out it passed between myself and the utility light I'd clipped to the underside of the hood It was almost totally clogged with what appeared to be mud and bugs!!! The AC condensor was clear, but the radiator was a mess. Since the OE was a TTow pkg 3-core and I already had the 4-core I made the switch and put the OE in the back garage attic where it still resides .... seriously in need of a good cleaning.

You might want to look at that too.

Louvers would let hot air escape but the air flow would go right into your vent/AC cowl air intake and with a 460 you need all the help you can get keeping the interior cool. Before I realized that I considered it but just couldn't bring myself to do that to Clyde's hood.

The puddle verifies overheating but the OE temp gauge is infamously inaccutate. Install a good hardwired auxillary gauge to get correct readings. Question to contemplate: Exactly what is the degree difference between "R" and "M"???

You might want to do a tranny temp gauge too while you're at it. Even with the larger radiator I noticed a drop in engine temps when I added a second auxillary tranny cooler in front of the radiator mounted one. The C6 doesn't lock up and torque converter slippage builds heat too.

 

There is a reason that all the factories went to cold air packages to duct cooler outside air to the engine.

 

Bear is right, that may be another aspect of your problem. I replaced the sad little "accordian tubing" air intake with 4" aluminum tubing and opened up a ~3x10 opening in the radiator header. The intake is screened with 1/4" hardware cloth and I still get a few bugs in there but that's what the air cleaner is for and the carb gets all the ambient temp air it needs.

 

I totally agree.... cold air induct that beast. i bet it will help. Also i have a 460 and am having problems with it cranking after it gets warm. should i wrap the starter???

 

An update:
I picked up a new bumper and when I removed the old bumper, the PO had tack welded spacers on the bumper mounts to move the bumper up so it sat higher in relation to the grille. I suppose he did it for looks, but it totally blocked the two oval vents just below the main grille.
I cut off the spacers and installed the new bumper in the correct location. Made a minor difference while under way (obviously getting more air in).
I also bought a $4 clear plastic fuel filter so I could see if the heat was causing issues with the fuel supply to the carb.
Took the boat out yesterday, and once again when we returned home and spent a few minutes parking the boat, the temp gauge jumped and the truck started running rough again. Jumped out and opened the hood this time and noticed through my new clear fuel filter that the gas was bubbling like it was boiling. Wild...

Looks like my main problem is primarly due to the fuel getting too hot.

So... would you recommend wraping some kind of heat shield on the fuel supply line to mimic the "Hot Fuel Option"? And/Or should I look into ways to minimize the underhood temps by using the header wrap on the factory manifolds and perhaps some kind of louvers or hood scoops to vent out the hot air?

I will do a cold air tube and enclosed air cleaner as soon as I can find a decent air cleaner housing. I also plan on removing the grill and carefully washing out the radiator in case its full of dirt and bugs as Clydesdale suggested earlier.

Thanks again

 

Just to clarify: the "hot fuel option" is the name Ford gave the hardware necessary for and capability to recirculate fuel in a loop from the fuel pump to the splitter just before the carb and back to the fuel tank again.

Ford recognized that they had a problem with fuel in the lines overheating on these trucks and tried to solve it by increasing the flow and continously "looping" the fuel to avoid it sitting in the line and overheating ... the "hot fuel option". They later did a recall that applied some snap-on type silvery fabric heat shielding material over the underhood fuel lines.

I have roughly double the amount of this recall insulation on Clyde and have still had problems with boiling fuel. I am of the opinion that it's not so much the underhood temperatures as the under body temperatures that are really creating the bulk of the heat problems.

My auxillary fuel tank sits just inside and parallel with the left frame rail. Inside the right frame rail, and not really all that far from the fuel tank, is the VERY HOT exhaust pipe and muffler. Additionally ALL the radiator heated air, all the engine block heated air and all the exhaust manifold (times two) heated air rolls out the underside of the engine compartment and past the fuel tanks. Granted it is mixed and "diluted" by underbumper air, etc., but it would be interesting to set a remote temp probe in this area and see what kind of temps are recorded in this area between the frame rails.

I have considered, not necessarily in any order of priority:
Wrap/insulate the front fuel tank,
wrap the headers,
wrap the header pipes,
wrap the Y-pipe,
wrap the muffler,
shield the fuel tank,
install a 3" exhaust system to reduce backpressure and reduce temps in the entire exhaust system,
install a "fuel cooler" in the circuit,
route cooler air to the fuel tank area,
throw my hands up ... maybe like the Ford engineers seemed to have done .... and live with it.

What I have done is insulate the fuel line under the hood to the "splitter" and run the front tank, the most vulnerable of the two, empty first to keep that fuel cooler and finish off with the rear tank. I've only had the rear tank hot once that I'm aware of. I carry an underbody spare tire and that may change the airflow enough to make a difference there plus the increased distance and proximity to the exhaust gives it a better chance to stay cool.

These are my thoughts and I've been working this truck with RV's, and having hot fuel problems, since 1996. Funny thing ... we never had problems with our identically equipped heavy towing trucks back when these trucks were current models. I think it's today's fuels that are causing the problems that were marginal then to be worse now.

The way I look at this is loving these old trucks we're all in this together and anything I can do to help I will. At this distance info is the best I can do. I'm open to new ideas myself.

 

Thans again for your response. Looks like you've been at this for quite a while!

Here is some more info about my truck that may help us both figure out a solution.

-Has a brand new 3" single exit exhaust from the "Y" pipe back. The "Y" pipe was new also, but he couldn't fab a 3" replacement so its 2 1/2". No cat. Huge muffler to keep the noise levels down, but its a straight through 3" to keep good flow. Its not mandrel bent so it has a couple crimps in the corners which necks it down to 2 1/2" or so. It had a rusted out 3" on it when I purchased it so I haven't noticed a change regarding heat or power output.

-My truck's front fuel tank pump died on the PO and he never fixed it. Its on my "to do" list, but for now I only use the back tank. No spare tire to shield my rear tank from heat. Just the big factory skid plate.

-My truck sits up. Its a four wheel drive and the PO had a 4 to 6" lift on it when I bought it. I did a SAS up front (because the TTB was shot) for a Dana 60 which lifted the front an additional 2" or so. So I should have lots of airflow underneath.

I really think my truck is too hot under the hood. When I went to open the hood, the hood release button you push down on was too hot to touch for more than a second. That's hot! I just don't know how to help it really. The air cleaner idea, louvers, etc would all work under speed with airflow to circulate from the outside. But my problem really stems from sitting in a stop and go traffic condition with no real help from the outside. The engine just broils itself.

I think based on our discussion I'm going to try the header wrap first and perhaps the fuel line wrap. And then go from there...

Thanks again for the help!

 

Agreed, I think your trouble is under the hood and likely not under the truck like mine may be. Low air flow seems to be where you have the problems. Increase air flow, decrease heat sources and insulate; fan clutch, radiator air flow, insulate the fuel lines and try wrappin' those underhood exhaust components.

Too bad good magic wands are so hard to find ......

 

What I did to increase air flow was to get rid of the clutch fan, as it never turns as fast as the engine (discounting any reduction in the pulleys). I tossed my clutch fan in the corner and install a fix 7 blade fan. It probably hurts fuel economy a little but for the increased air flow AKA cooling, it is worth it. Oh, how is your fan shroud? If the fan and shroud are not correctly aligned it will also hurt air flow.

Oh and not one of those stupid "flex" fans either. A real solid stamped steel, large big bladed fan. I found one on a older F-250 from the late 60s.

 

The header insultaion wrap will work on the fuel line as well. You can also add additional ducting (fairly inexpensively) with inlets located either at/below the front bumper, wheel wells, etc. to help move the air, lowering underhood temps. Louvers is a nice idea too, but can be costly.

 

Ducting cool air around the radiator will result in and degraded cooling system resulting in a hotter running engine, which will be as bad or worse. Air into the engine compartment must go thru the radiator or the radiator doesn't cool as well as it is suppose to.