Bypass hose

Tony Radford · #1 (**permalink**) 01-11-2009, 07:01 AM

Is it bad to plug the bypass from the water pump to thermostat housing? I'm installing an expansion tank and I don't see any way to connect the two with the spacer installed.

Tony Radford · #2 (**permalink**) 01-11-2009, 07:10 AM

Never mind. I did a search. I'll figure out a way.

marcalan · #3 (**permalink**) 01-11-2009, 07:13 AM

my expansion tank is connected via a T in the heater hose line coming from the water pump.

wtm442 · #4 (**permalink**) 01-11-2009, 07:17 AM

Yes, you want and need the bypass.

Its easy to install the short rubber hose. First, lube up the inside of the hose with a little grease (white lube, etc). Now bend the hose in half so the open ends are almost touching each other. Position hose so that both open ends are touching the metal ends on the intake manifold and water pump.

Now let go. The hose will spead out and automatically suck itself into the installed position. WOW. Did you forget to put the clamps on the hoses? Sometimes its easier to leave them off and then loosen the hose clamps, spread them open and put them on last.

RedBarchetta · #5 (**permalink**) 01-11-2009, 08:38 AM

FYI. I used Goodyear hose #60687 to make the correct bypass section. It has the right natural bend ("S" curve) and you just have to make the cuts in the right place on either end to fit. Works like a charm with no kinks. I just went to my local "hard core" auto parts counter and they let me walk into the back room and size various hoses they had hanging up. Don't try this at Autozone or Pep Boys.

-Dean

PANAVIA · #6 (**permalink**) 01-11-2009, 02:16 PM

Tony -- i am sending you a PDF.

Tony Radford · #7 (**permalink**) 01-12-2009, 10:08 AM

Thanks guys. Dean, does your bypass hose have a kink in it? I assume it needs to be as non-restrictive as possible. I have no idea as to the amount of pressure that hose sees during operation.

vanoochka · #8 (**permalink**) 01-12-2009, 11:12 AM

I don't know my hose number, but I bought it at Kragen auto parts and it looks like an elongated "S". I gave it a slight twist and made it into a loop and it fits perfectly with no kinks.

marcalan · #9 (**permalink**) 01-12-2009, 11:38 AM

There should be no kink in the hose.

RedBarchetta · #10 (**permalink**) 01-12-2009, 12:19 PM

Quote:

Originally Posted by Tony Radford

Thanks guys. Dean, does your bypass hose have a kink in it?

None. Nada. Zip.

PANAVIA · #11 (**permalink**) 01-13-2009, 01:23 AM

coolant pressure in the system is less than 15 PSI.

Tip: take a piece of coat hanger wire , cut and bend to the shape of hose desired, copy down the sizes of the hose ends and go to the store with this and match things up.

ou812545 · #12 (**permalink**) 02-21-2009, 04:01 PM

My SPF with a 418W has the bypass blocked off (no bypass hose) and I have not had any cooling or leaking issues.
Why is it so important to have the bypass hose installed?

Thanks,
Dan

vector1 · #13 (**permalink**) 02-21-2009, 04:18 PM

Quote:

Originally Posted by ou812545

My SPF with a 418W has the bypass blocked off (no bypass hose) and I have not had any cooling or leaking issues.
Why is it so important to have the bypass hose installed?

Thanks,
Dan

keeps coolant flowing when thermostat is closed, or you can drill holes in the thermostat and leave the hose off. i think.

Barnsnake · #14 (**permalink**) 02-21-2009, 07:56 PM

If the water cannot circulate within the engine when the thermostat is closed it will heat up unevenly. It is likely the water in the heads will be boiling before the water contacting the thermostat is anywhere near the temperature required for it to open.

Removing or drilling large holes in the thermostat will resolve the uneven heating issue, but it will cripple the thermostats ability to accurately control the engine temperature. The engine will be slow to warm up or may never reach proper operating temperature. If all you do is race on hot afternoons, that's fine, but every other engine should have a functional thermostat and a circulation bypass.