Help desperately needed!
 

I have been having cooling problems with my 2007 cummins 6.7. It will evacuate my coolant from my radiator to my overflow tank when put under a load but if I drive it easy it's fine. I have done multiple head gasket tests that have all come up negative and I don't know what It is or what else to try any ideas?

have you tried your thermostat it might not be opening all the way.

Yes I tried that and the pressure still built up and evacuated coolant

Is it foaming out?

Could it be egr cooler plugging up?

what tests have you done for headgasket failure? lots of block testers will not work properly. #1 cause of that is head gasket failure. hoses will usually swell up also. gonna take alot to overcome rad cap pressure.

also very possible the egr cooler has an interal leak, and is pushing exhaust into coolant.

The truck will build up pressure and put coolant in my overflow tank and pressure will be there for about 2 days. My egr and dpf is deleted. I have tried the compression gas tester that's about it at the moment and the guy I have taken it to says it might be the turbo putting boost in there is that even possible?

this sounds just like my head gasket failure on my 08 a couple years ago.

if you take that turbo apart, all the coolant does is run through passages to cool the actuator. I have heard people say that, but i dont believe thats your issue. You have a blown head gasket. Seen it alot, typically on deleted trucks with stock headbolts and a programmer. Get a new headgasket, and studs, and make sure you have the re plumbing line that splices the coolant line from the egr cooler back into the head. if you dont have that, it can put a hot spot on the head, and pop the head gasket that way.

make sure also you deck your head. :hellox: