excessive coolant usage

Its not normal on an engine of any age. The cooling system is a closed loop - you shouldn't be adding anything to it at all. If its getting into the engine oil, you have a major problem that needs to be taken care of at once. An engine oil analysis would tell you the story for $40 or so.

 

could be the egr cooler, oil analysis at the ta/petro is around $20

 

The very first thing you do is get the rad cap tested, and if you buy a new one get it tested. Stant is having a problem. Freightliner sells a good cap.
Places that leak small amounts, I would be looking at the sleeper and cab heater connections, and the drains for the heaters.
Look for the cheap stuff, first!

 

before i have the same problem with coolant,after changing headgasket,everythink was normal

 

I would be looking at the water pump first if it doesnt leak from the waterpump itself then its going right in the oil.

 

Me too. Do look at the cheap stuff, but do an oil sample! Is it pumping out the top thru the cap? Either the cap is junk, or you're adding ore compression to the system (compression from the cylinder is coming out throught the coolant system/new head gasket)

 

Just purchased a 2007 and was losing coolant.The seal on the top of radiator was oozing coolant.Replaced radiator with metal after market and no problem

 

Sounds like you possibly could have counterbore issues. Have seen this a lot with high mileage 60's. If all the obvious checks have been done, rad. Cap, EGR cooler, air compressor,etc... Pull the exhaust pipe off the turbo and check turbo outlet for signs of coolant, white streaks. If there is then cylinder head needs to pulled. If you find the head gasket to be leaking. 9 times out of 10 it was due to liner protrusion issues, ie..counterbores. Also there is a certain reman cast of the EGR cylinder head that is known crack.