Hi fellow RV’rs. I have a Keystone Cougar 1/2 ton series I bought new in 2018. Right before my first trip I conducted a thorough safety check which included checking the propane lines. I discovered a gas leak at the regulator coming from the pigtail line to one of the tanks. The dealer gave me a replacement and everything was fine.
Now, I am in the second week of a three week trip and traveling through Colorado. Every evening as the temperatures cooled I would notice a distinct smell of propane. I chalked it up to my neighbors propane campfire until the third night when they were not there. I began investigating and quickly discovered that the smell was coming from my propane tanks. This time it was the pigtail leading to the other tank. I could hear and smell the gas leaking. I did a soapy water check of all the connections prior to departure and have not removed the propane tank cover or moved the lines in any way since then.
I went to an RV dealer in Durango to get a replacement line and they told me the type of connection I had commonly failed. In my case, 2 for 2 = a 100% failure rate. Attached is a picture showing the type of crimped hose connection that leaks. The area where the brass connects to the silver metal part is where the gas leaks from as indicated by the blue arrow. I am just posting this so other people with similar connections can be aware. My suggestion would be to replace the lines. The line on the right tank is the one previously replaced.