Cracked Radiator Bypass Hose

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Mar 19, 2011
Comaville in the Midwest
Was working on the '94 earlier today and while changing the injectors I gave the radiator bypass hose a wiggle and it cracked! The hose, not the nipple. Then when working my way back to removing the rigid hose the nipple cracked off the top of the radiator tank. I have never seen a rubber hose turn rigid like a brittle plastic and actually crack. I have rebuilt the engine 150K miles ago and replaced all the hoses and radiator. I must have used some hose from a sketchy supplier. Has anyone ever come across this before?


May have been cheap fuel line with a similar ID instead of coolant hose. Wasn’t OEM, says made in the USA.
FUEL LINE HOSE same part number hose.
HYPALON COVER Hypalon - Wikipedia should not act the way it did. Likely not using this polymer.
Why would someone use fuel line instead of coolant hose In that application?
Is this like using a soup spoon to stir tea?

No, much worse :)

I replaced a line (s/c) that was marked fuel line and it had turned hard/rigid like plastic, just broke into pieces like brittle plastic. Replaced with coolant rated hose. Posted a thread on it a few months back.

Found it -> S/C Throttle Body Coolant Hose

I'm getting convinced that coolant does bad stuff to fuel line hose and one really should be using coolant rated hose for coolant.

It's the alcohol content of the coolant. "NOTE: Not to be used with fuel over 10% alcohol."
The HYPALON has been out of production for 10 years in the USA. Must have been old stock or overseas sourced and brought back to the USA.

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