That's just what my factory V8 did shortly after changing the stat. The
first long run showed no symptoms, but on the return journey I was aware
that the needle was moving very slightly either side of the N. As I watched
it moved further up the H side each time until it started going into the
red. I knocked it out of gear, let the revs drop to idle and checked the
oil pressure and it was fine, indicating to me that the internal temperature
was OK. When I got home I let it idle for a while, the temp crept up, the
fan cut in, the temp crept down, the fan cut out, just like normal. As it
was doing this the idle oil pressure also fell slightly, again, just like
normal.
Conclusions from other people are that I got a duff stat. Doing very little
mileage at the moment so haven't swapped it again yet, local journeys have
shown no tendency to swing since that one day. The swinging is exactly like
when the car is warming up and the stat cycles a few times before settling
down to the N (except that normally it starts with big swings and then gets
smaller), which has always been much more pronounced on the V8 than the
roadster.
PaulH.
http://freespace.virgin.net/paul.hunt1/
-----Original Message-----
From: Simon Holt <simon.holt@tdsi.co.uk>
To: 'mgb-v8@autox.team.net' <mgb-v8@autox.team.net>
Date: 12 March 1999 11:06
Subject: Cooling
>I'm new to this list but I've searched the archives and can't see any
previous
>discussion.
>
>The temperature gauge on my 1973 factory BGTV8 cycles from Normal to Very
>Hot (in fact, off the end of the scale). I don't believe this represents
the true
>engine temperature because the electric fan never cuts in unless the car is
>stationary for some time. I've spoken to one other owner who has exactly
the
>same problem. Incidentally, I believe all parts in question to be perfect -
the
>engine has only 2000 miles after a professional rebuild; the rad, hoses and
>'stat are new.
>
>Is this to do with the famous air-lock problem caused by the low mounting
>position of the header tank? If so, is the temperature gauge representative
of
>water temperature throughout the engine? And if so, why doesn't the
>temperature in the inlet manifold water jacket get high enough to turn on
the
>fans? Alternatively, if the temperature gauge is NOT representative of the
>engine temperature, is it actually representative of any part of the
engine; i.e.
>is there a "hot spot" which (if I do nothing about the problem) could over
time
>become "damaged" in some way?
>
>Simon Holt
>
>
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