[Spridgets] Ignorance is bliss
davriker at nwi.net
Mon Apr 13 21:16:40 MDT 2009
Think it though. It is really a "radiator bypass hose". When the
thermostat is closed, the water pump is still spinning, and still wants to
pump. Water comes out of the top of the head and usually goes to the
radiator, cools down, then is pulled by the waterpump from the lower hose
and pumped back into the engine. So until the thermostat opens, the water
pump just pulls the water down from the head, and circulates it back through
the block in a smaller circle. This allows the engine to warm up more
quickly, and more uniformly without hot spots and cold spots. Also, for
those of us who still run a heater, that bypass hose means warm water begins
flowing to the heater core almost immediately, instead of needing all the
water in the radiator to be heated first, which in a cool or cold day could
be...NEVER.... Yes, on a hot day, that is water that in theory is getting
recirculated without ever seeing the radiator, but is is a very small amount
compared to what passes through the much larger radiator hoses. So, in a
racing motor, block it off, in Death Valley, block it off, for a street
driven car in cooler weather, leave it be.
----- Original Message -----
From: "rrengineer @dslextreme.com" <rrengineer at dslextreme.com>
To: "Hal Faulkner" <frog.aye at gmail.com>
Cc: "Spridgets" <Spridgets at autox.team.net>
Sent: Monday, April 13, 2009 7:05 PM
Subject: Re: [Spridgets] Ignorance is bliss
> Vizard's book addresses the bypass hose on page 501 under "Thermostats".
> The bypass hose is actually called the "thermostat bypass hose". It
> connects the water jacket adjacent to the thermostat to the water pump.
> was fitted to A series engines up to the early 80s. Vizard calls the
> hose a nuisance and the hole in the pump and the hole in the head should
> plugged. He says then drill two 1/4 inch holes in the thermostat to
> overheating in the event the thermostat gets stuck closed.
> On Mon, Apr 13, 2009 at 6:43 PM, Hal Faulkner <frog.aye at gmail.com> wrote:
>> I believe the bypass is there in order to cause the thermostat to open a
>> little sooner than it might otherwise.
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