6.7 Disappearing antifreeze
 

I have a 2015 6.7 diesel with an on going problem. Antifreeze in the secondary reservoir near the back of the motor, top right side keeps disappearing.

It has been in to Ford 5 times so far.

Ford replaced the EGR cooler the first time. Worked for 3 months then problem returned. In May of this year they thought it might be a head gasket or possible crack in a head so they went as far as to replace the entire engine block and heads.

Both repairs worked for a while but the problem keeps returning. Two weeks ago it happened again. Suddenly it was down 1/2 gallon for no apparent cause. Took it back to Ford who pressure tested it ( again ) overnight and no real problems they said. Pressure dropped from 15 psi to 8 psi on a below freezing night but they didn’t seem concerned.

Any one else have this problem on a 6.7, and if so what was the cause?

Thanks,

Jim

PS..no external leaks anywhere

I’ve been wondering myself where the coolant level is suppose to be at in that reservoir that is on the drivers side.
When the engine is running it’s in the middle of resivoir when it’s shut off you cannot see it in the resivoir.
Where should the level be when shut off cold?
2017/6.7

I’m pretty sure the fluid level should always be visible at some measure otherwise it would be impossible to tell what is really in the tank. I think as long as it’s at similar point when cold, and likewise when hot, is the only way to predict a constant. Hot levels are usually higher than cold.

When the levels start varying from their known constant is when consumption is occurring some where. In my case it has to be being consumed as there is no evidence of leaks. The question is where is it going? As yet Ford has no clue.

The turbo cooling line is a prime culprit when it's hard to find. Just about need a snake camera, borescope, to see it.

So here are mine, cold pick is at 40 degrees this morning, dark/hot, just shut off, eot 208


https://cimg9.ibsrv.net/gimg/www.for...be4e2962f.jpeg

https://cimg0.ibsrv.net/gimg/www.for...6805f38d1.jpeg

Hot, 208 EOT, this is the normal level for me
https://cimg2.ibsrv.net/gimg/www.for...fcdbfab6e.jpeg

That’s what mine also looks like on a normal cycle.

My problem is every now and then the fluid disappears entirely. It required over 1/2 gallon to bring up to Max line last week. For some unknown reason the system suddenly starts consuming fluid, then will work just fine for a few months....rinse and repeat.

I’ve not added any in the year I have owned this one. FWIW, my rzrs do the same thing, winter or cold startups, you cannot see the fluid in expansion tanks, once warm, they are back at normal level. If I add more on the rzr it just pukes it out while driving once it warms up.