6.0 coolant smells horible

[84monteman]

I have a 05 6.0 that the coolant just smells horrible, makes you want to gag,

I feel like most likely cause is egr cooler starting to go.

has anyone else seen this?

or is it possible head gaskets? but I don't feel like that would be it, I feel like the egr cooler is more likely the cause,

its hard to describe but kidna like a rotten egg smell.

 

[lmorris]

My past experience with smelly coolant were mostly restricted oil coolers. Not always a bad EGR cooler. I would advise changing both anyways if it is the oil cooler. As far as head gaskets go...they usually blow out all the coolant so there's nothing to get stinky. 

[Keith Browning]

In my experience I have noticed rancid smelling coolant was contaminated with fuel or more commonly had previous repairs where the system was flushed with VC9 iron cleaner and not properly and completely flushed. I had a couple of coworkers that never took the time to fully flush cooling systems. leaving any of that cleaner behind quickly degrades the coolant and will contribute to damage that we are trying to eliminate.

[cbriggs]

2nd the plugged oil cooler. The coolant flow is reduced to the egr cooler causing the small amount of coolant that does make it through to boil in the cooler, causing the brown color and horrible smell. If left the egr cooler will soon start dumping coolant. I've seen some like this run for quite some time, others rupture the cooler long before the coolant starts to stink.