I HAVE A 2007 6.0 WITH 197000 MILES. I have noticed that after about 1000 miles my truck loses 1/8 to 1/4 inch in the coolant resivor tank. I have checked and had head gaskets checked to make sure i didnt blow a gasket that not the problem, i have checked and have had all of the hoses checked for holes or lose connections. Once again not the problem. I replaced the coolant over flow tank to make sure that wasnt the problem and its not. so im lost. If any one has any ideas i would greatly appreciate it.

 

Are you only filling it to the MIN line ? it should have a little sticker on the degas bottle because they found that the MAX line was too high for the expansion. does it go empty o does it just go down to a certain point and stop "leaking"? each truck settles out to a sightly different level. You can check the little hose on the EGR cooler to the oil cooler, it is a common leak point.
6.0 egr cooler - Bing Images
see that little blue hose, that is the one, the original might be orange.

 

ok i konw its coming some where from around the tank, because i wash the motor and then checked to see where i had coolant it is from around the tank. yes once it hits a certain level it stops. but it very low in the tank where it stops and once it gets there i usually dont give it any time to get any lower because i dont want to risk any thing.

 

My truck settles in just about 1/2" below the min line and will stay that way for years, just monitor it and see if it doesn't stop loosing coolant.

 

ok, thanks i appreciate the help. il post again if if doesnt stop and continues to lose coolant

 

Possible you have a small crack in your bottle. I had one and it would loose a few drops every time I started it.

 

i just replaced the bottle. is there any way that icould be the cap i have on it isnt allowing pressure out when it should ?