Re: [Amc-list] Nick Frank or Davis - thermostats

[Frank Swygert <farna@xxxxxxx>]

Nothing wrong with running a 180 like Davis recommends, but I always run the factory 195. If the rest of the cooling system is up to snuff it won't over heat. Is it actually boiling over, or is the gauge just higher than you like it/think it should be? That could just be the break-in. It takes 2-3 thousand miles to really break-in, and it WILL run warmer than "normal" during that time. It should run just over the thermostat rating. An engine with a good cooling system and 180 t-stat shouldn't run over 200 once broke in, a 195 t-stat engine will run up around 205, but shouldn't go over 220. water boils at 240-250 degrees with a 16-17 pound pressure cap. If you haven't changed your cap in the last 3-5 years you might want to get a new one just to be safe. 

Did you change the sending unit for the temperature gauge? If not, get a GOOD replacement. I'd go to Ron Francis Wiring or one of the gauge manufacturers to get one, maybe even the local Jeep dealer. I wouldn't use a Wells or any of the generic Auto Zone parts. NAPA Balkamp parts used to be good, but I think some of them have been coming from China or Mexico lately. It's hard to get good parts for some of the simplest things now! 

On the gauge, assuming it's stock, it reads 130 on the "C", 171 at the beginning of the normal range bar, 242 at the end of the bar, and 270 on the "H". That's from the 74 TSM, but is pretty close for all AMCs. That means that right in the middle of the normal bar is about 205. A 14 pound cap (stock for most AMCs raises the boiling point to 242 degrees, so anything after the end of the bar will start the radiator boiling over. With a 16 pound cap the boiling point will be raised another 5 degrees to 247. Each pound of pressure raises the boiling point about 2.5 degrees. As long as it's not boiling over it's fine. The center of the bar is fine for a stock engine (any of them!) with a 195 t-stat, and a little over when under strain or on a very hot and humid day won't hurt. Just don't get to the end of the bar! Some modern engines use a 205 t-stat and run 210-215 normally. Not much margin for boiling over, but as long as everything in the cooling system is good it should never 
 boil over. 

--------------
Date: Wed, 19 Mar 2008 14:05:50 -0400
From: "Thomas, Jeff" <jeff.thomas@xxxxxxxx>

Guys,
Do you have a recommendation for a thermostat brand/heat range on a
newly rebuilt, mainly stock AMC 360 4BBL. I have the 6090 heads from an
73 
AMC 401 if that helps. After my break-in, my engine seems to be running
hot.

-- 
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)


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