Questions for the PROs of trucking/mechanics.. Coolant pushing out.

As long as you don't see this when you pull the head

 

Not a gallon a day and not while the trucks running but our cascadias leak in real cold weather. Heater lines shrink a bit from the cold and force coolant out.

 

Just like Heavy said. Several different tests need to be run to figure out what is going on before you get to deep.
I recently had a customer come in that was pushing water out of his tank. I checked for pressure build up when revving up truck with a pressure tester and it did not build up. The temperature would not get above 175 because his fan is always running (another issue for another time). I figured out it was a ground problem so I installed a temporary ground and got the temp up to 210 and it did not push out. I installed a new cap and put a antifreeze jug with a bungie cord attached to his overflow tube. He came back the next day and it was full. So I ran a test with the testing fluid to see if there were any compression gases. There were none. I removed and replaced his air compressor. No more issues.
Now here is what other mechanics in the area had done to the truck before this. He had it overhauled. It pushed out water. They removed the head and installed new gasket. It pushed out water. They had the block counter-board. It pushed out water. Then another mechanic installed not one but two head gaskets. This is the tester I use. I highly recommend it. http://www.uview.com/index.cfm?dsp=productdetail&id=45700&productid=5122

 

I've used that kit. Definitely money well spent.

There are parts changers and there are mechanics. The ones that take the time to properly diagnose are worth paying the price for and the truck you described is proof of that.

 

I also tested for compression gases after installing the new compressor and found none. Installed the "test" jug and no fluid in jug after several hauls.

 

How much for the tester?

 

I googled it and it was $86.00.
Amazon

 

Just bought 1 $86. With tax at FGI.