240sx blown coolant bypass hose!!

[Slow540]

Hi everyone,

Got a problem. Have a stock 93 240sx. I just fixed a coolant leak (heater lines) and flushed the system. Then topped the coolant off a couple times after a few short drives once it cooled down. Drove the car for 500 miles and it ran great. I noticed the coolant bypass hose swell quite a bit, the one that goes from the exit to the inlet. Well today it blew open like a balloon. Any thoughts on what's going on. I've searched but no luck. After 500 miles I can't imagine trapped air in the heater core would build up that much preasure to blow the hose open. Wouldn't that air get circulated after the thermostat opened up.

[CSUPUEBLOTIM]

Was the hose the blew one of the new ones you replaced?

[Slow540]

No, I replaced one of the heater lines. This is the bypass hose for when the thermostat is closed the water can keep circulating through the block. It flows from the exit (top) to the entrance (bottom). I think I had air in the heater core and didn't fill the system properly. Thought it was fine because it never showed any signs of overheating. With my experience, a little air in the system would cause the temp gauge to rise a lot due to the air being hotter than the coolant.

[CSUPUEBLOTIM]

I would probably just replace it and fill the system and be sure to bleed it.

[Slow540]

Dealer wants $50 for the hose. Anyone found a better option?