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Posting-Version: version B 2.10.1     9/27/83; site hplabs.UUCP
Path: utzoo!watmath!clyde!floyd!harpo!seismo!hao!hplabs!piety
From: piety@hplabs.UUCP (Bob Piety)
Newsgroups: net.auto
Subject: Toyota Heater problems
Message-ID: <2175@hplabs.UUCP>
Date: Thu, 2-Feb-84 15:46:45 EST
Article-I.D.: hplabs.2175
Posted: Thu Feb  2 15:46:45 1984
Date-Received: Wed, 8-Feb-84 03:08:31 EST
Organization: Hewlett Packard Labs, Palo Alto CA
Lines: 21

Has anyone had trouble maintaining a comfortable temperature inside their
Toyotas?  I have an '83 4x4 pickup and cannot set the heater temperature
properly.  There is a large hysteresis in the control action: The
temperature gets too warm so you turn it down...it stays too warm, you turn
it down some more. Then, suddenly, its completely off and you get cold air.

Its also very dependent upon the engine RPM.

I took the heater valve apart and noted that the portion of the valve that
restricts the flow of hot water is SPRING LOADED?????  It seems as though
the hysteresis was designed in, for some obscure reason.

A friend, with the same type truck, reports the identical problem, although
Toyota claims that it is the same heater-valve design they've been using for
years, with no complaints.

Any suggestions, comments, similar experiences?

Thanks in advance.

Bob