2008 F-350 Diesel Using Coolant, But No Leaks???

[MuleDeerCrazy]

So maybe somebody else has experienced this with their diesel?  I noticed after hauling the camper and boat on a couple trips last year that my coolant reservoir was empty.  I took it into the shop and they checked it all out and "pressure tested" the coolant system (whatever that means) and found no leaks... said it was all good, topped it off and sent me on my way.

Ran it around for months just fine and after the next trip working it hard again, it was low on fluid in the reservoir.  I took it in again and again the said it all tested out fine, no problems.  However, this time they put dye in the coolant and said if it does it again we will be able to put it under a light and find the leak from the dye and be able to identify where it's leaking.  It finally goes through some more coolant and I take it back in so they can track the dye markings.  Just got it back and they said there're no leaks, since there was no dye on anything?

Maybe somebody can help me out here... if I top the reservoir off and work the truck hard and it's a half a quart low when I'm done, don't that mean it's leaking somewhere? 

The Ford dealer is adamant it's not leaking... any ideas or thoughts?

Thanks!

[Slimdog350]

If there is nothing visual on the outside my first thoughts would go to inside the engine. A bad egr cooler or a blown head gasket? If you have any access to tools you could put a pressure gauge in place of the radiator cap and run it until the engine warms up. If it build pressure quickly or until the relief on the gauge pops off you have combustion gasses getting into the cooling system. Ask the repair shop if they checked it for an internal problem. Good luck!

[whacker1]

If there is nothing visual on the outside my first thoughts would go to inside the engine. A bad egr cooler or a blown head gasket? If you have any access to tools you could put a pressure gauge in place of the radiator cap and run it until the engine warms up. If it build pressure quickly or until the relief on the gauge pops off you have combustion gasses getting into the cooling system. Ask the repair shop if they checked it for an internal problem. Good luck!

this is what is I was thinking"head gasket" slight issue that is sending the coolant out the exhaust in the way of steam

[snowpack]

could be the shaft for the water pump.  Just enough tolerance to have drops every now and then work out along the shaft.  Same shaft that runs the fan (usually).  The fan draws in the air with any rain or road moisture and directs it toward that part of the engine after pulling it through the radiator.  That water could be washing off the dye.

[6x6in6]

What Slimdog350 said.   

[Mudman]

Radiator issues common.  Remember reading about degas bottle and high boost causing an issue to, whatever that means?

[STED9r]

Pull the egr valve and look down the intake and the valve. If the intake or valve is sticky and wet, guess what..........
Egr coolers are simple fixes. Don't fall prey to the diesel rags(magazines) they're there to flush your wallet. Do not do an egr delete if you tow, its there for more than emissions.
Bullet proof coolers for later style models followed IH in early coolers and work great. Again though, don't get the wallet flushed with the remote oil cooler kit from bullet proof, it taint gonna help here. Have the dealer or someone with ability to get reading on coolant and oli temp. More than 10° differential change out oil cooler while you've got it apart.

[buglebuster]

If it was a 6.0 id say head gasket but thats not as common in the 6.4. Could be that, but probably something to do with your egr cooler. Head gasket would have shown up on the pressure test, and you would probably have white chalky substance around your degas bottle (overflow resivor)

[MuleDeerCrazy]

Ya, they said it wasn't a head gasket, so they must have ruled that out with the pressure test?

Guess I'll have to ask them about the EGR cooler... is that not something they would normally check for this?

That something a guy can swap out in the garage or is it shop work?

Thanks again for the feedback!

[jackelope]

6.4 egr coolers go bad. We've done more 6.4 egr coolers recently than 6.0's I bet.

[jackelope]

How many miles on the truck and what's your location?

[shoot-em-dead]

I'm not a mechanic so I'll just throw this out there. Isn't there coolant lines that run under the dash to the heater? Could it be leaking under there and still pass pressure tests?

[buglebuster]

You can do it yourself, but you better know more than basic mechanics lol. Will probably take a good day.

[jackelope]

There's 2 coolers, a horizontal and vertical. Depending which one, the cab might have to come off to access. Easiest way is to pull the cab and do both.

[kenzmad]

There's 2 coolers, a horizontal and vertical. Depending which one, the cab might have to come off to access. Easiest way is to pull the cab and do both.

Who the hell designes a truck where any type of fix requires the removal of the cab? This is frigging absurd