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Re: How hot is too hot?

To: Bob Howard <mgbob@juno.com>
Subject: Re: How hot is too hot?
From: Tab Julius <tab@penworks.com>
Date: Mon, 06 Sep 1999 21:18:33
Although I don't disagree with the blockage diagnosis, my question relates
to thermostats themselves.  I know that from other cars that I've owned
that we've occasionally installed a "summer thermostat" and a "winter
thermostat".  Since I live in New England where it can get to -30 (that's
30 below 0) degrees in the winter, or over 100 in the summer - there's a
temperature range for you! - it's desirable to vary the thermostat by the
season.  Does such a thing exist for MGs (probably) and do people switch
out (perhaps not so probable)?

- Tab


At 08:33 PM 9/6/99 EDT, Bob Howard wrote:
>Bob,
>  That the temp gets above the thermostat setting is not unusual, but for
>the temp to reach 100C often is not right.
>  The purpose of the stat is to establish the minimum operating temp of
>the engine. It does that by circulating engine water that is over the
>stat's rating out to the radiator for cooling. The stat can cycle open
>and closed in its efforts to maintain the operating temp. The actual
>operating temp is established when the heat into the water (waste heat
>from the engine) is in equilibrium with the head transferred to the air,
>and that is usually much hotter than stat rating.
>  Assuming that the gauge is telling the correct temp,  80C is about
>right for the engine. 90 is OK, but I wouldn't want to be above that very
>often.   If you're running hot, first thing to do is to check the timing.
>Set it to 0 (the book setting) or 4 BTDC (my preferred setting) but do
>this the static timing method.  If you don't know what I mean, ask and
>I'll describe.
>  I read that it is possible to install the fan blades so that they push
>air forward. Check that they are on properly.
>  Is there water moving visibly in the radiator tank when the engine is
>hot? You should see some swirling that indicates the pump is pumping.
>  But, I'm sorry to say, the problem is very likely to be a clogged
>radiator or clogged block.  The front right corner of the block, behind
>that little drain tap, will fill up with an incredible amount of sediment
>and block the proper flow of cooling water.  The square casting on the
>side of the block, half-hidden under the carbs and exhaust manifold, has
>one, two or three holes in it that go to the water passages inside the
>block.  If plugged, the engine runs hot. Solution to that is easy-pull
>out the "freeze" plugs, ream the holes, install new plugs. Reinstall
>carbs and exhaust pipes. 
>  What I would recommend is to check the timing and the fan blades, then
>run a radiator cleaner in the system and flush it well.  Won't hurt and
>may help.
>Bob
>TD MkII
>
>On Mon, 6 Sep 1999 15:30:49 EDT BobMGT@aol.com writes:
>>On a hot day my TD's temperature gauge gets up to 212. All I know is 
>>that 
>>this is above the thermostat rating of 190. Is something wrong if the 
>>temperature gets above the thermostat rating? What temperature should 
>>be 
>>considered too hot? I found nothing in the workshop or owners manuals 
>>regarding temperature, maybe because the early models had no gauge.
>>
>>BTW, I tried some Redline Water Wetter and it made absolutely no 
>>difference.
>>
>>Bob Donahue (Still stuck in the '50s)
>>EMAIL - BOBMGT@AOL.COM
>>52 MGTD - under DIY restoration NEMGTR #11470
>>71 MGB   - AMGBA #96-12029, NAMGBR #7-3336
>
>
>

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