I have a 1999 F550 stake bed w/ manual transmission. When towing an 8000 lb trailer up an extended grade (maybe 1/2 mile or more), the temperature climbs to the top of the range. I always get out of it before the gauge gets outside the safe range, but I'm guessing it would peg if I let it.

It also seems like it lacks power in general, and especially when towing. I would think with the low gearing (2300-2400 RPM at 60 MPH), this thing should not even know it's pulling a 4 ton trailer, but I regularly have to drop a gear on anything more than a slight grade, which means I'm under 50 MPH and the loaded semis are passing me!

There are no OBDII codes. I will take it to a stealer if I have to, but I thought I would put it out there for opinions before I sink the cash. Any ideas?

Thanks,
Rich

 

sounds like the thermostat is bad.
do you have any gauges?
sound like a boost leak making it weak.
my 550 would pull a house up a hill with no problem.

 

When it pulls the hill, does the fan kick in as the temp climbs? It should have a really noticeable sound .

 

How many miles are on your tired truck? Have you checked your Under Valve Cover Harness on each side to ensure the plug is fully inserted? The clips get weak and wiggle loose. If you are going to do this, then this modification is called the 50 cent mod on this forum. Do what these guys above have recommended for looking at the thermostat and check your fan clutch to ensure operation. The drivers side valve cover will take just less than an hour to remove to inspect the harness. The passenger side take about an hour to remove. I can post a video from youtube for the 50 cent mod if you are going to do it.
Don't take your vehicle to the stealership
This forum is really good at giving you the info. You just need to apply the info in the form of wrench in hand and eyes on truck.
Did I mention that I hate me some stealership.
Dwayne

 

Matt's got the scent I think.

By temp do you mean water temp or EGTs? If EGTs I'd first look for boost leak at the back of the turbo, the up pipes. This would explain the lack of power and high EGTs. If water I'd swap out the thermostat and see if any change. Lets assume the rad is full of coolant.

To Carltonwebbs point, the normal fan is a steady on and off, right? That's all I ever hear, but I figured it might stay on if needed.

 

Sounds like possibly a couple of different issues.

Have you checked fuel pressure?

Boost leaks like Matt suggested?

Those would be for the lack of power.

For the overheating, if we are talking coolant temps, I agree Do you hear the Fan Clutch engaging?

That roar of the clutch I don't think can be confused with much else if you've ever heard it.

The fan is always turning if that's what you are asking but it's sort of like a thermally controlled fluid coupling that increases friction at temperature to drive the fan more.

 

maybe i cant hear but i dont think i have ever heard the fan on any of our trucks, and i have towed some heavy junk? and they have never gotten hot.

 

I could hear the fan on my truck kick in rolling from stoplights when I was pulling our new fiver home a couple weeks ago during 95 degree weather. Granted, it would slowly cut back out once speed increased and more airflow pushed through the radiator. Also have heard it when stuck in traffic on interstates not pulling and temps at 100+ outside.

To the OP, pulling 8k up a slight grade with what appears to be 4.88 axles should be a piece of cake and definitely shouldn't overheat the engine. Thermostat and clogged radiator fins would be my first two places to look. General lack of power is probably unrelated to the cooling issue and could be sourced in any number of areas on an older high-mileage truck. I'll let others troubleshoot that one.

 

Thanks everyone for the suggestions. I will be using this posting as my checklist while working on the truck this week! I feel better getting into it now with this direction.

The overheating that I mentioned is coolant. I haven't noticed any fan noise. I know that diesels can overheat if they aren't running right, due to bad injectors for example. But the truck doesn't smoke and runs fine other than the subject problems. It was running even worse and smoking some until I changed the CPS several months ago.

1fixitman - I searched the 50 cent mod, but there are so many posts that I'm afraid it will take me longer to get to the instructions than to do the work! If you can post the youtube link, it would be great.

FYI, the truck has 162k on it. It came with a business that I bought, and the guys tell me it used to really run. I'll let you know what I find out.

Thanks,
Rich

 

Here is the post I usually put up for the 50 cent mod or the UVCH 50 cent mod.

You know I have to pop in here and ask if the Under Valve Cover Harness (UVCH) connector has been looked at and the 50 cent mod done? 50 cent mod video here
2001 F350 7.3L Turbo Diesel, UVCH - YouTube

How to do it written down from my post in another thread. The video above is not my video but is a great training tool.

For the 50 cent mod you will need two quarters, a short 13mm socket, deep 13mm socket and a universal or wobble short extension to get the back bolt on the drivers side and a few of the bottom bolts on the passenger side, a 13mm wrench and a long(6-8 inch) extension. Various wrenches and sockets for pulling harness connector and Intercooler boot clamps.
Only takes 20-25 minutes to pull the Turbo intake hoses and Turbo pipe(metal) on the driver's side. Be careful with the boots. Just be easy with them.
Don't pay too much attention to all the oil inside of the inlet tube and metal pipe as you can clean them any time IN THE FUTURE.
Right now focus on taking the valve cover off. I take out the stock filter and all the inlet tubing going to the turbo then I gently shove a not so good towel into the stock filter box AND lay a moving blanket( very thick folded over several times) over the battery and stock filter box so I can lay on it while I take the Valve cover bolts out. Be careful of the towel in the stock box for the sensor in that box. They are fragile. I am short so please laugh and work with me at the same time.
Unbolt the 42 pin electrical connector on top of the valve cover. If you have an air compressor, now is the time to blow any debris around the valve cover down out of the way.
Take a PICTURE or take note which fasteners are bolts and which ones are studs with a nut to mount something else to. You will want to put it back exactly as it was. Get the 13mm socket and a 13mm wrench.
DO NOT TAKE THE Positive Crankcase Vent or CrankCase Vent(CCV) DOGHOUSE OFF UNLESS YOU HAVE THE FOUR ORINGS TO RESEAL IT
4 Viton O-rings to reseal the Crank Case Vent cover
OR THE ORINGS WILL SWELL UP AND BE NO GOOD AND YOU WILL LEAK OIL ALL OVER THE PLACE UNTIL YOU GET THE NEW ORINGS.
Using the 13mm wrench carefully remove the bolt just above the CCV dog house and leave the CCV in place. You will not be able to use the socket with the CCV in the way. Now you can use that 13mm socket and take all the rest of the bolts out. The hardest one is on the rear of the cover and you can not see the bolt without a mirror. Don't worry about the mirror, just loosen it and place the bolts to the side. I use a 5 gallon pail to put my fastners in. Slow down when you get the bolts loose and keep a tight grip on them unless you like fishing for metal in the pit of hell. I put a tarp under the truck for items I drop to easily find them.
When you pull the cover loose, be slow and easy so you don't put any debris in the VC area. If your harness connection is loose, very gently push the connector towards the top of the VC gasket and let the clips clip UPWARD into place. You could also unclip it and inspect for burnt connectors. Place the connector back firmly in place. Now take the quarter that you have shaved off right at the top of the hair line on the head and slide it in round side down and flat, cut side toward the TOP of the valve cover. DO NOT FORCE ANYTHING unless you have a fresh Benjamin Franklin laying around to spend on a new gasket/harness.
The clips should be clipped fully in and pushing up whilist the quarter holds the clips up. The flat spot gives the valve cover enough room to be installed and keeps the quarter from going anywhere.
If you want to you can now check the torque on the:
Lower injector hold down bolts at 120 INCH lbs.
Rocker arm bolts at 20 Foot lbs
Valve cover bolts when reinstalled will be 96 INCH lbs.
Verify all of the injector connectors are secured and clipped
Verify all of the glow plug wires are tight.
Do everything in the reverse order to put it all back together. Wipe the oil coated pipes down to remove any excess oil and start on the passenger side
Remove the intercooler pipe. You will figure out that you have to move it above the turbo to get it out. Lots of room above that turbo. I loosened my boost pressure gauge and tied it back with string or a small bungee.
Bungee cord the two heater pipes toward the passenger side fender. I put the Moving blanket on this side but did not lean on the A/C pipes. Same thing on this side except you have a bolt holding down the Engine Oil Dipstick so be careful with the dipstick. Only pull the dipstick high enough to remove it from the stud. The bolt near the AC compressor is tight but you can get to it with a few extensions and a deep socket. Same one as the oil dipstick. Note the stud positions again. Don't loose the heater hose clips because they are 28$ at the dealer. Loosen and remove the rest of the bolt/studs. Same thing as the driver's side from here.
Man, that is a lot of typing. Talking thru it is much less time consuming. LOL. Put a wrench in your hands and get to work. The sooner you get it done, the sooner you can drink that favorite cold beverage and relax that another inexpensive mod is done and you will feel better for not spending any money at the mechanic shop or Stealership It might even run much better or have gained some power back. Same torque values as mentioned above. Be careful whilist VC's are open. If it rains you need to shut the hood all the way immediately after you remove the blanket and slowly slip the VC in place. I hope this helps and is not too mundane. I prefer air tools but you need to put it back together with regular rachet/wrench and get torque values correct.
Dwayne

 

I do need to mention you need a torque wrench with a 1/4 inch drive with inch lbs and a 3/8 inch torque wrench with foot lbs.

 

Here's the 50 cent mod.
https://www.ford-trucks.com/forums/9...-cent-mod.html

Also I believe I recall reading at one time that a bad coolant reservoir cap can cause coolant to overheat because the cap isn't holding back the pressure like it should.

Something worth checking if indeed your thermostat is good and allowing coolant into the radiator.

 

X10 on the up pipes. Look for soot behind the turbo, at the connections between the pipes and the collector. If you see any black sooty stuff... they are leaking. It might be hoo of you to crawl under the truck with a flashlight and take a peek at the drivers side pipe to collector connection from underneath.

Drop your tank and get rid of that horrible mixing chamber. I.e. the hutch/harpoon mods.

The fuel rail crossover from Riffraff performance made a world of difference for my truck. It cut the cackleclatter in half.

Clean clean clean your engine bay. When your motor bleeds... you need to be able to find the wound. Meaning... hard to spot leaks on a dirty motor.

How dirty is the air filter?
These motors like to breathe... when they cant, they are slugs.

Fuel pressure gauge. That can go a long way to helping us help you.

First and foremost. DROP YOUR TANK AND REMOVE THE MIXING CHAMBER... i.e. the hutch mod.

Oh and did i mention the hutch mod?


No oil additives. Your motor doesnt like it.

Xtof


Hutch mod...

 

I have head the same thing about the caps. I guess you don't want the caps that "click" Apparently they were problems in about every Ford vehicle they were used in. They do not allow the system to pressurize which raises the boiling point of your coolant.
As to the power loss I would make sure you are building boost and that your fuel system is in good order, no clogged filters. IF you have a metal tank your intake screen could be clogged up too. (not sure what the 550's ran for tanks. I might be way off base here.)

 

Well, I know it's been a while, but here's the update...
I simply did not have time to work on it, so I took it to a highly recommended local indy. Here's what he did:
- Replaced leaking exhaust manifolds
- Repaired turbo leak
- Replaced bad #8 injector (he used a different injector than the other 7.)

The truck is running much better, but still not as well as it should. The indy said cylinder 8 is weak, probably due to the bad injector and no wash-down for so long. I think it's about the best that it's going to get. The real test will be if it doesn't overheat when the warm weather returns. If it doesn't, I'll be happy. Thanks everyone for your help.

Rich