Coolant leak but can't find where is from?

I also heard from other driver, he told me to check the sleeper heater control valve first. Long story short $35 control valve and problem solved, the valve is electric over air and when it goes bad you put 100+ psi to the coolant and it blows it out the exhaust, freightliner only problem though? is that true?

 

Another comment from other post but he has shown white smoke when he idle. My truck doesnt show white smoke at all.


Glad they found the problem.

Just for the record, the Shaker I drive has the Detroit 60 Series, and, at about 400,000 the EGR cooler cracked and coolant began going away, but, not in the manner you might suspect. The leak allowed pressure from the EGR to enter the cooling system, and one by one, every section of the cooling system developed leaks. Hoses, radiator, bunk heater core, to name a few, all began leaking. But, not at once. We would repair a leak, then the next weakest segment would blow. It took two weeks, and, a cooling system pressure check to finally figure it out.

 

I found the leak here. Is that cause coolant to leak like 1/4 after 500 miles?

 

######. It drops that low after I had it right below Max. And only happen drive 324miles and had to drive some hills on Blacks mountain NC I40. I didn't see any other leak when I got to Knoxville TN. Spoke to several driver they said it is def. Egr cooler that burns the coolants while I'm driving.
Any other input? I don't see sign of white smoke or anything so.

 

Yes I did oil sample before I bought the truck and it came out good. I found out my head was replaced new as well.