By Pass Hose part #????

[tdw6974]

I give up!! :shrug:Need to order the Bypass hose that runs from back of Thermostat/water pump housing to the rear Housing on our 1986 13b I can't seem to find in my parts book. Need pictures:D Thnaks Tom W

[C. Ludwig]

That's because no such thing exists. What does work is a 3rd gen rear iron to throttle body hose. N3A1-13-681A

[cherbi7]

Do you need the Bypass hose can you just block them off?

[C. Ludwig]

Do you need the Bypass hose can you just block them off?


You can block them off. Do not use a simple rubber cap by itself though. They will dry rot and eventually fail.

[tdw6974]

Do you need the Bypass hose can you just block them off?
Not sure. We do not run themostat and the housing is plugged. 2 times I wish we did not have to, but ir seems to move coolant.

[C. Ludwig]

You don't need the flow. The stock setup doesn't flow much at all through that line. The line runs from the rear iron to the throttle body thermowax cam and from there to the water pump. The thermowax has a pin hole size bypass which, I would guess, is only there to allow any air bubbles to escape.

On engines where we don't use the thermowax, I typically cut the hose barbs off and drill and tap the water pump and iron for a 1/4 NPT plug.