Heater hose help

[Wrangled13]

So I blew the heater hose (pump to core) last night, got some cut to fit, which is what every parts store says it is, and it goes like this- pump outlet- 3/4" to core 5/8 ", from what I have been told. I cannot get the core side to clamp down enough to not leak or blow off and drain coolant. What have you guys found that works on this? Its a '79 CJ5 by the way.

Thanks in advance

 

[PaRenegade]

I'm assuming you bought the 3/4" instead of the 5/8" hose. If it was the other way you could warm up the 5/8" end, lube the inside with some water pump sealant or I've even used grease, and force it over the pump 3/4" outlet and clamp. After a few heat / cool cycles it will be form fitting.
But since you've got the opposite issue, find a 3/4"x5/8" barbed reducer fitting for hot water and 2 clamps (at Lowe's or similar store) and then get a short 6" piece of 5/8" and splice your hose prior to the core outlet.

 

[Posi]

I'm running a 360 and my remaned water pump has the 7/8” outlet feeding to a 5/8” inlet to correct this I simply bought 3' of 7/8” hose and cut a small piece of 5/8” hose to install over the heatercore inlet then slid the 7/8” hose over it. I never had an issue doing it this way and find it easiest.