12.7 Detroit Coolant Leak

Liner o-ring leaking , that plug is your tell tale hole each cylinder has one

 

Yup, liner weep hole. The liner has 2 seals at the bottom, 1 sealing the oil and the other sealing the coolant. Inbetween those seals is a hole to the outside so you can tell when the seals go.

 

Depends on how much coolant you're using. If it's running good and only leaks a little when it sits, I'd let it go. The fix is not an easy or cheap one. You have to pull the liner, which can easily turn into an expensive inframe.

We had a 2001 Sterling with a 12.7 doing the same thing years ago. The truck wasn't worth doing an inframe on, so they were going to retire it and sell it off in a group sale. We put some radiator stop leak in it and it stopped leaking. It ran for 2-3 years after that with no issue until they finally did retire it due to age, but it still didn't leak and ran good.

I'm not a big fan of stop leak, but the alternative is to tear the motor down. If it doesn't work and you tear it down, it'll get flush out anyway, so it's worth a try.

 

I got c13 2004 freightliner. Do you know if I have those weep holes? Thank you

 

What cause the seals to go

 

What cause the seals to leak

 

What cause the seals to leak

 

Age mostly. Honestly every engine I've owned , once they get past 12-14 years in age there running on borrowed time.
Liner O -rings and oil coolers etc etc all start too leak..