Anyone know of a source for an OEM spec. thick wall t-stat bypass hose? I've tried everything produced today. I don't like any of them. They physically expand and contract with RPMs like a breathing balloon!!! I have resorted to putting an old serviceable thick wall take-off on. The wall on the old take-off is about double the thickness of whats currently available. The reproduction wire hose clamps bottom out before the new thinner hose ever gets tight. Not doing it in my engine bay.

 

What's the wall thickness on your "take off" old bypass hose?

Also - be aware that the repro double-wire bypass hose clamps are NOT the correct size...they're a step up in size (diameter) compared to the factory originals so they're going to nearly bottom out no matter which hose you use.

I measure three AC Delco formed bypass hoses (AC/D # 14206S , GM #88907203) and they appear to be just about .1875 wall thickness (3/16") and two Dayco hoses that were about 11/64" wall thickness.

Have one "unknown" that is definitely thicker than the AC/Delco and Dayco versions - it's closer to 7+/32" but the label is mostly missing (shows "C03...." on the torn away label and "3330" ink-stamped on the hose ...no names, etc). Not for sale but maybe the number will lead to something.

 

Not sure which one I put back on the car. It is in great shape. I have 3 different hoses in front of me now. 2 are new 1 is very old ~30-40+years old. The one I put back on the car is a take-off which is very similar in dimension to the old hose seen below and almost as old if I had to guess. It's a Gates but I cant read the #s. The repro hose clamps almost bottom out on the old skool thick hose currently installed...AND more importantly, the old thick hose doesn't expand/contract/swell with water pump pressure like today's cheap junk does. Hummm wonder where the cheap junks country of origin might be

Hose dims are as follows:
-New Delco pn 14206S/GM88907203, ID = ~0.185, OD = ~1.130 (local GM Delco dist).
-New GM pn 393508 ID = ~0.165 OD = ~1.060 (Fusicks).
-No numbers many-year-old hose, ID =~0.210, OD = ~1.20.

Older is better IMO. I agree with the fact that the repro hose clamps are too large. Hey everyone, send a letter to all your favorite repro houses and tell them to fire the engineer's as someone doesn't know what they are doing(overseas). And they are doing by the millions.

Guess we're stuck with a risky old or new hose unless someone has a secret source for the correct wall size hose and corresponding clamps. Ill look at the Vette stuff. They may have the correct clamps as the Vette guys are sticklers for authenticity.