WHY is this engine overheating?(truck, not tractor)

[workinallthetime]

call the last owner and find out if they had the intake mainfold off, if they did they might have reversed the intake manifold gaskets. the v6 block off plates on the manifold go on oposite of the the v8. i cant tell you withoout seeing the engine if they are on right. if they are on wrong this will cause the engine to overheat or run hot. there are little tabs on the gm gasket that have pointers on them, and say "this side up". this is an easy mistake and i have seen it many times, and with the t-stat out the problem goes away.
BUT you need a v8 radiator also

 

[Hooked_on_HP]

OK, now that we know it has the V6 computer we can figure the rest out. Go to tbichips.com and tell them what motor was in the truck and what is in it now. They will make you a chip so the computer will operate corectly with the V8. You may also have to change the fuel pump or regulator. They are verry helpful and can tell you just what you need to do.

 

[Jstpssng]

OK, all of the above is true. I did finally figure out that the bottom half of the radiator is plugged, which is causing my immediate problems. The other issues need to be addressed if I want to depend on it. Right now I'm making a list of everything this truck needs, for a final tally before I start spending. It's going to be more than I'd hoped, (New tranny, radiator, computer) but in the end I'll know what I've got.

I've already figured out that the rear locker isn't in my budget.

 

[bluetc30]

sounds like a blown headgasket

 

[Ford960]

It appears that some people here are not clear on the workings of a thermostat.
First off a 180 degree thermostat OPENS at 180 degrees, it has nothing to do with keeping the temperature from going over 180 degrees, it will however try to keep the engine from running cooler than that. But if the engine cooling system isn't operating correctly the thermostat WILL NOT limit the temperature, period.

Also, removing the thermostat will allow the coolant to flow through the engine fast enough that it doesn't remove the heat and the engine will overheat just the same. So removing the thermostat and running the engine is never the answer for overheating.

The easiest way to test a thermostat is to place it in a pan of water on the stove. Measure the opening temperature with a candy themometer and compare with the number stamped on the bulb. If they are close to the same put it back in the engine.

The themostat is there to maintain an even operating temperature in the engine and can fail either open or closed, we all know about the overheating that a closed one can cause but one stuck open is just as bad. I had a F-350 diesel that had an open thermostat and it took forever to warm up in the winter and for the heater to work. And that was in SC where it really wasn't cold. Also the engine rarely came off the high idle and the glow plug light came on everytime I needed to start it even though the truck was just parked.
I finally replaced the thermostat (which is a real chore on a 7.3 N/A) and what a difference. Got better fuel mileage too since it was operating at 180 degrees, the optimal temperature for a diesel engine.

 

[RobJ]

It appears that some people here are not clear on the workings of a thermostat.
First off a 180 degree thermostat OPENS at 180 degrees, it has nothing to do with keeping the temperature from going over 180 degrees,........


The themostat is there to maintain an even operating temperature in the engine and can fail either open or closed,

You sort of contridict yourself here. First it has nothing to do with going over 180, then it's there to maintain an even operating temp.

The engine, cooling system, etc are all designed to keep the engine at that temp. That's why 180 or 195, etc is the temp of the thermostat. If the thermostat is 180 and you are running temps at 200, 210, then something is not working correct.

No I don't believe all systems are designed that well (ok this is where I contridict myself... ). My son has a V-6 mustang. Only an electric fan. The thermostat is 195 if I recall. But the fan will NOT come on (with the AC off and the car is going overt 45mph) until the temp is something like 215 degrees. So the cars temp runs up and down!! Now here is the really stupid part, if he turns the AC on, the cooling fan stays on all the time keeping the engine at a normal temp. I also think the cooling system on my Kubota isn't enough, but I think after some work I have that problem working not, time will tell this summer.

As mentioned my wifes 350 Suurban never moves no matter what, same with my V10 Ford. A properly designed cooling system will maintain the engine temp at a full load all day every day. On the stationary power units I used to work on they ran 24/7, 365 and the temp never moved at full load.

Good Luck,
Rob

 

[Ford960]

Let me try this again, a thermostat is there to help the engine reach operating temps and to maintain that temp. It does not limit the maximum temperature that the engine runs at. The thermostat doesn't care if the engine reaches 300 degrees it only cares that it is fully opened at the temperature that's stamped on the bulb. At that point the coolant flow in the engine is at it's maximum, the thermostat can not and is not designed to limit the higher temperature.

As far as the electric fan, the advantages are numerous. They save fuel since the engine isn't directly driving the fan, they allow different engine mounting configurations like transverse, and they allow a more even engine temperature.
The A/C condenser is mounted in front of the radiator and the electric fan comes on when you turn on the A/C to provide increased air flow and to offset the extra heat load from the condenser to the radiator.
It's an old trick to turn on the A/C in a vehicle with an electric fan that's running hot, turning on the heater on high helps too. The fan will run anytime the A/C clutch is engaged.

And yes, in most vehicles the fan will come on when the engine temp reaches 257 degrees and that's why removing a radiator cap when the engine is overheated is about as dangerous as it gets. The sudden drop in pressure will cause the coolant to flash into super heated steam and explode out of the opening. Standing over or in the way of this steam can take the skin off bones.

 

[jfox]

Timing not ADVANCED will make them run hot.
What about backpressure in the exhaust?
How is the power level?

 

[Jstpssng]

Timing not ADVANCED will make them run hot.
What about backpressure in the exhaust?
How is the power level?

Power level is great... wish my 2005 F150 could match it off the line!

I did finally figure out that the bottom half of the radiator is plugged, causing my initial problems. (Coolant from drain petcock is cool, when engine is hot)


The other issues mentioned above will have to be addressed to get this vehicle right; but now I can run it more than a mile from home and figure out if they'll be my problems, or those of somebody more proficient at repairs. (I.E., how many other problems must I face?)

Thanks again to everyone for the help.

 

[BobRip]

220 is not too hot with a 14 lb pressure cap.

ron

I agree in general. You are only overheating if you are loosing water out a good cap. Caps are only good for one year. I have a tester and when I test one that is a year old it leaks down.

Replace the cap. If you don't loose coolant it is OK. What was the outside temperature during this test?