Date: Thu, 12 Dec 2002 14:20:44 -0500 From: "g c" <nbtrownopsamet.on.ca> Subject: Re: in-line block heater for 92 900T
*e: SaabCatalogue.com: search on Engine Block Heaters* After realising that the web site needs cookies enabled..... I finally got to see two heaters.... one that is the standard type of engine block heater, which replaces a frost plug; and another which is a lower(?) rad hose heater that would heat up the rad, but I'm not sure about how effective it would be in heating the block (wouldn't the thermostat stay closed, and block off any circulation through the block?) I agree with the concerns about uneven heating, and also have a concern about the heater coming loose/out (happened to someone in this group, and was written up recently; might be rare, but prefer not to join an exclusive group who've experienced >that< failure!!) Next thought - can a tank heater be connected so that it takes from the block low down, and returns into the block through the heater core bypass? the heater core won't get hot, but the flow through the block should be improved without the resistance of flowing through the core. (might need a check valve somewhere, or the heater system always shut off when the block heater is on) Whatcha all think? anybody got a diagram of the heater hoses? and *re: Walt Woytowich who wrote: what is described is just a plain old tank heater but installed in a manner for which it wasn't designed. The tank heater circulates coolant by convection which means the hoses must be short and vertical. The original installation method was to connect the intake of the tank to a drain plug hole in the engine block and the outlet to a "T" in one of the heater hoses. Even with such a direct routing the flow wasn't always reliable, this sometimes led to hardening of the upper hose. The efficiency of the tank heater is about half that of a block heater, this is reflected in the the wattage recommendations published by heater manufacturers. About the block heater: the cost is certainly low but what is the cost of installation? A block heater may ( will?) heat the engine unevenly,- engine temperature will vary from near boiling next to the heater to almost ambient at the extremities, according to a heater manufacturer. I found that even an engine with aluminum heads and block had a temperature difference of 26F between the left and right sides of the engine when heated by a 600 watt block heater in a -40 degree chamber. I would be most interested in learning the average temperature of a crankshaft in such a situation i.e. steel crank aluminum block. Walt*
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