Hi all, Happy New year,
Hey just noticed my coolant with about 30k on it turned a dark chocolate color in the last 2k miles. Anybody else noticed this? Going to the dealer on Thur for oil change etc. Going to have it flushed and changed.

 

doesn't sound good. should never turn that color. there may be more going on.

 

Agree. Something is not right. Have it checked ASAP and let us now what they find.

 

I also agree with the others. I have 36K miles on mine and it still looks the same as it did when it was new.

 

My only guess is oil cooler failure. Something has to be contaminating the coolant. Definitely sounds like a trip to the dealer.

 

Matt that was my guess too, but I hope it is a one way trip for the oil. If coolant goes into the oil, it's new engine time. Been there, done that with a 6.4. I think I would call them and ask them to come tow the truck to the dealer.

 

I would take that to the dealer on a flat bed.

 

Agreed! I'm not familiar with the what or how of oil cooler failures on a 6.7, but it isn't worth risking. If you are covered under warranty, they will tow the truck on their dime. You would hope that the oil runs at a much higher pressure than the coolant and you shouldn't get coolant contamination in the oil, but once you shut the engine off, the coolant system is still pressurized and can force coolant into the oil since the oil system is no longer pressurized.

 

Take the coolant cap off or at least loosen enough not to build press.

 

If it is the oil cooler then good news it sits on the oil pan, outside the motor. So it won't be such the pita to fix.