OEM Decades old clamps deform somehow, OEMs had Fillister Head Slotted Screws. The repros available over the past 30-30 years with the round head slotted screws are not perfect. I have a been lucky to have rounded up a quantity of 40's 1-1/2" Double Wire Hose Clamps that I save for my Jeeps, Dodge and CCKW. They do not allow leaks.
The worm type clamps are also excellent. The Worm type clamps were developed for aviation in WWII. The P-51's in ETO had a similar Glycol dripping problem and found that they had to use two clamps on each end.
Something else to consider, this seems to be more of an issue with the vehicles that have straight sections of fabric reinforced straight hose such as used on many Jeeps and not the molded curved hose. If your straight hose is old enough (maybe swollen some) it may be deteriorated enough on the inside to be affected by "wicking" which will seep thru the ends.
The straight hoses (Gates Green Stripe) on my MB, CCKW are all approaching 15-20 years old and will be replaced with new sections and all will have the vintage double wire clamps to prevent seepage. They may not be exactly "factory, but do look vintage enough to fit the bill.
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