I installed Jag deluxe oil coolers on the down tubes on my 04 FLHTCI last year. They worked great for oil cooling. The units were shipped with black fuel/vapor lines which I used to connect the units to the oil circuit. I noticed today that when I started the engine with high cold oil pressure, 60 psi idle, the lines were bulging out. When the oil heated up and the pressure dropped they lost the bulge. I checked the hose and Jagg supplies standard 3/8 ID SAE30R7 line. This line is only rated for 50 psi max. My bike pulls that pressure hot at 3000 rpm cruising. I believe Harley gets their cooler kits from Jagg also. Not sure but they look the same. I will be changing out my lines to SAE30R9 high pressure hose, 180 psi immediately. I think this is piss poor quality for such a simple item that is shipped with the kits. Once the engine was hot and oil thinned out, I snapped the throttle past 3000 rpm and the lines bulged out again. I’m sure they get worse under high heat conditions. I haven’t heard of anybody blowing lines but it sure doesn’t look right to me. Ya’ll running coolers may want to check your hoses.