06 LLY - Bad Head Gasket?

[joed]

While towing yesterday, I was heading downhill with the grade braking humming along (~3,800 rpm), like I've down many times before.

Then I notice a smoke screen coming from the truck, and within several seconds the 'low coolant' light appeared on the DIC. I couldn't really pull over easily, so I limped to the next exit and now I have a steady stream of coolant dripping down, basically in line with the turbo/bellhousing.

I can't find any visible ruptured hoses/line from above - the only place I can see the drip coming from is from the right rear corner of the passenger head. I can't tell if it's coming the gasket itself or above it?

Any other possible source from above? I thought when the head gaskets fail they typically pressurize the cooling system rather than create a outside leak, especially one as bad as mine is.

Hoping it's something more simple I'm overlooking, but...

Thanks.

Joe.

[DmaxMaverick]

It could be a head gasket, but that would be an extremely rare condition of failure. I'd suspect something a bit more common, such as EGR, heater hose, or turbo coolant line, especially in that area. It shouldn't be that difficult to locate the large leak.

[joed]

Well, I lucked out. The lower EGR cooler hose ruptured. Too bad a 4 inch piece of hose ruined my camping trip, but glad it's not something more serious.

Was not fun to change, though. Felt like I had to take half the top of the engine to get to it!

I've been lucky so far and haven't had to work on this Dmax much, but when I have it makes working on 6.5s seem easy...

Thanks, Joe.

[DmaxMaverick]

Thanks for the update. It's good to hear it wasn't something serious. How did the line "rupture" (pic)? How many miles on the truck?

[joed]

I forgot to get a pic. It split longitudinally, about dead center - basically at the 'bend' of the hose, not that it has much of an angle. Not sure why they even have a hose, seems like a solid tube with a bend could have worked since the tube ends practically join up. Probably to make the cooler easier to remove?

Truck has 118k on it and has been in service about 11 years (early 06 MY).

Thanks.

[DmaxMaverick]

Soft-line coupling isn't uncommon on an engine. It breaks vibrations and harmonics, where rigid lines may tend to fail or cause other issues. A drawback is flow disruption, which effects efficiency. End-to-end rigid line assemblies are usually more cost effective to manufacture, and simplifies initial assembly.