[totally opinionated screed follows <g>]
Everyone seems to think that a 160 degree thermostat means your engine will
run at 160 degrees. Maybe, if the ambient temperature is below freezing. At
which point you would regret it because the heater wouldn't do diddly.
Seriously, the normal operating temperature of the engine (in moderate
conditions) is going to be somewhere in the range 170-200 degrees. Remember,
all the thermostat rating means is the temp at which it starts to open. Once
it is fully open, it's up to the car's cooling system to limit the
temperature. In summer driving, that's going to be around 190, or more. This
is entirely based on the heat output of the engine and the size of the
radiator (assuming everything in good condition).
I've said it before -- I see no point in using 160 degree thermostats
whatsoever. Look at it this way:
- In the winter, the engine temp stays at 160, and you don't get any heat
from the heater;
- In the summer, the temp climbs rapidly past 160, at which point the
thermostat is wide open and has no further effect -- might as well take it
out;
- Or, say you've installed an oversize radiator and quadruple fans, and the
engine actually does run at 160 -- what have you accomplished? How is that
any better for you or your engine than running at 190 with your "winter"
thermostat? Cooler (other than in the sense of "cooler than boiling") does
not mean better.
On the other hand, if you use a 190 degree thermostat year round:
- In the winter, you have a nice, toasty (well, at least noticeable) flow
of heat;
- In the summer, the thermostat actually modulates the engine temperature
and keeps it at a stable 190, which, you may note, is the straight-down
position on the dual gauge, indicating that it is the nominal (or "normal")
temperature.
In your own words, "No boiling over, water loss or other overt hot signs" --
what would make you think that it was "too hot"?
Far from being "too hot", 190 is actually a more efficient operating
temperature from a thermodynamic standpoint. And it is far from being close
to boilover -- if you have any pressure in the system at all you can get to
215-220 degrees or so. And unless you're stuck in stop-and-go traffic on a
sweltering day, you'll never even get close to that.
Sorry to run on like that. In short:
- 190 is "normal"
- chuck the160 thermostat
on 7/31/01 7:09 PM, dave houser at mgs4dave@warwick.net wrote:
> To those folks with early MGBs:
> Trying to get an idea of what other folks' cars are running at compared
> to my two b's, 64 and 67 BGT.
> I've got 160 degree thermos and find on a day like today, the temp was
> around 190 in the roadster. Thinking my GT with only 750 miles on new
> engine and running the same, as too hot. No boiling over, water loss or
> other overt hot signs.
> Guages checked out fine with external thermo tests.
> What think?
> TIA and cheers,
> Dave Houser
>
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the red one with the silver bootlid.
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