there is a nylon washer on some fittings, and a rubber O-ring on others. depends on your pressure and return lines. all lines will still rotate even when the fitting is tight, so dont confuse that with a loose line. they are engineered that way to compensate for body flex and vibration. your best bet is to remove the intercooler tube, put a drain pan down, and take both fittings out. you can get the nylon fittings or O-rings at any parts store very cheap. if the fittings themselves (not sealing washers) seem worn out, just replace the whole line. i paid $35 for a pressure line. also gives a good reason to flush the system since you have it apart. also very easy. just have to jack it up and cut the wheels left to right similar to bleeding brakes. if you have questions, i'll give more details.
