willys_wonka
Member
Hi all, I'm in the process of possibly purchasing a 1980 F-40 Trojan, and had a good look at the 6-71 engines today. They have both had a great deal of recent work prior to selling, including rebuilding both heat exchangers and replacing all cooling hoses. They light up fast although it's quite cold right now and run well. What has me concerned are small bubbles coming past the (new) cooling system caps and into the coolant overflow reservoirs. I expect coolant to expand past the caps but my prior experience with diesels is that any gasses in the cooling system points to head gasket leakage. I really don't expect this to be the case here as the mechanics recently overhauled the cooling system and pressure tested it to the tune of very big bucks, and both engines are bubbling at exactly the same rate. My question is it normal for this to occur?