coolant loss out of overflow hose!

I had the same problem on a 3406E. 7# cap also.....changed to a 10#.....end of problem

 

are you sure it doesnt smell like diesel?

 

i had same problem end up being a cracked liner. or it could be a compresser isolate the water supply to compresser but run water through it with a gardenhose and see if that stops the bubbles. if not find out if they checked liner protrution when they had the head off. cat has very low specs for this i learned the hardway.

 

No diesel in coolant.....cap solved problem for me.....been ok for over a year now

 

had same problem with my 3406e it had air in the cooling system. theres a petcock valve on the upper rad hose. run motor cold not hot and bleed off air.sounds crazy but it worked.o i forgot to tell you open heater valves or youll keep getting air. Walt

 

it was worth a try.have you done a leak down test yet?

 

Try the cap replacement first off. It is the cheapest and most likely. Of course another possibility is that the cooling system is overfilled, so it boils out when it gets warmed up....

 

Try a new cap first. I had the same problem on a 3406e. Cracked liner was the culprit.