Hello everybody, I have a 7.3 1992 F-250 4X4, I changed the water pump a few months ago after realizing it was leaking and after that everything was OK, lately the truck has been "loosing" water on the radiator, about a gallon and a half every 3,500 miles and no water leaking that I can see, I have checked the oil to make sure there is no water on it and there is none, I have read about cavitation problem in this kind of engines, how does that problem presents itself? Do any of you think that (Cavitation) may be the reason the truck is loosing water on the radiator or it may be something else, another kind of problem or is it normal?
Thanks in advance.

 

Check inside your cab on the passenger side floorboard. If the carpet/insulation is wet then your heater core's toast.

 

Thanks for the answer, I have already checked that and it is dry, any other possibility?

 

There is some evaporation of water thru the cap on the overflow tank; although a gallon and a half between oil changes is too much.

Note, make sure you don't overfill the overflow tank as it may overflow when you drive; Follow the cold and hot level markings on the side of the tank.

I did have a problem once after I changed my rad hoses. The new hose had a puncture which would only spray antifreeze when the pressure in the cooling system was high. When I would open the hood you could not see anything. One day I was just twisting the new hoses the right way with the truck still hot and found the leak. Very frustrating as the new hose you would think be the last place to look and the leak often does not show up when you do a cooling system pressure test.

Another time I had a hoseclamp that did not properly tighten and would again only spray when the truck was under load.

Look for white powder dots on the inside of your hood, on your engine or air cleaner (dryed up antifreeze). Leaks you can't see when the hood is open are some of the most frustrating there are. Keep twisting hoses and tightening clamps while the cooling system is hot and under pressure.

Sebastian.

 

I plan on doing an antifreeze change. How do you do it and where do you fill it up? There is no cap on my rad., the cap is on the revervoir on the driver side.

Also, which type of antifreeze should we buy to prevent caviation.

Thanks

 

No cap?

I am now running Fleetguard pre charged antifreeze.
It is purple.

Caterpillar uses red pre charged extended life.

There are others that are precharged.

Or you could just use DCA 4 and your choice of low silicate antifreeze.
Stuff like regular Zerex is loaded with silicates to protect all the aluminum in modern auto cooling systems.

 

Check the overflow tank for a hairline crack in the bottom. Mine was leaking there and had to replace. Very hard to see under there but it was there. And you should have a radiator cap on the left side of the radiator on the top. this is where the overflow hose goes from the tank to the radiator.

 

I will check again, but there is no cap on the top of the rad. I always check the reservoir for antifreeze. Interesting isn't it?

 

Travertine,
Check the overflow tube carefully for a leak between the radiator and the overflow.
Also remove the overflow tank and look for a crack on the bottom.

When cavitiation is the problem the water winds up in the oil.
Check the smell of the exhaust, if the coolant is entering the combustion chamber the exhaust will have a sweet smell to it, although your leak is so small it might not be noticable.

Also inspect the bell housing sides, any leak that goes into the valley drains out he back of the valley unless the truck is parked nose down on a steep hill.

 

I went to my local IH dealer, and asked about cavitaion.. I have a 6.9 and he mentioned I didn't have to worry that much. He said the 7.3's do because of the thinner cylinder walls (bored out 6.9).. Is this not much of an issue with the 6.9?

 

Correct, the 7.3 is a bored out 6.9, therefore the 6.9 has thick cylinder walls and cavitation isn't a concern.

 

I would not say it is not a concern, but I would say it is less of a concern.
The difference is a 7.3 is a 6.9 bored 110 thousandths.

The length of time and the number of miles you will get out of either engine will come into play eventually.
Why take a chance on cavitation if you don't have to. Diesel engines are expensive to replace or repair.

 

So Dave, What shopuld I be running in my 1984 6.9 for coolant? Do I need special coolant, or an additive or what? I am confused. Right now all I have is some regular antifreeze and mostly water. BTW I live in FL. (hot weather)

 

I would go with antifreeze from IH with the DCA premix.

 

I am using Fleetcharge from NAPA now.
Pre charged with DCA 4 and pre diluted to 50/50 mix.
What could be easier.
That way I also know I can get compatable test strips when I need them.