Re: [DML] Cooling system

[srubano@xxxx]

Another test you could do along with testing the otterstat is to 
unplug the wires from it and place a jumper wire between them. This 
should keep the fans running continuously (with the ignition key in 
the run position). If you notice that it's still "chattering" then I 
would look else where in the circuit, start from the beginning. You 
may have a break in a wire or a loose connection.

Steve

--- In dmcnews@xxxx, "Walter" <Whalt@xxxx> wrote:
> David,
> 
> You say that your fan fail light flickers and the fan relay clicks
> frantically sometimes when the fans come on. It shouldn't do 
this. I am
> suspicious that you have a bad otterstat. This gadget is a switch 
that is
> activated by a bi-metal strip. Two different metal alloys are 
layered
> together. One alloy is more temperature sensitive that the other, 
so when
> the temperature changes, it tends curl or warp. This triggers the 
switch.
> It sounds like your problem may be that something inside this 
switch is
> loose. When working properly, it is supposed to switch off when at 
several
> degrees cooler than when it switched on. This is supposed to 
reduce the
> chance of rapid cycling. In your case, it sounds like this 
mechanism has
> gone to the other extreme where the coolant has to be luke warm 
before the
> otterstat will switch off. When the switch comes on, it may be 
holding the
> contacts closed with only mediocre force which would explain your 
flickering
> light and chattering relay.
> 
> I have done this test before: take the otterstat out and put it in 
a
> shallow pan of water with a thermometer. Heat it on a stove with a
> continuity meter allegator clipped to the otterstat. You will be 
able to
> see at what temperature it switches on and off. While you are at 
it, check
> your original otterstat the same way and compare. Since you seem 
to be
> having such bad luck with otterstats, I suggest checking any new 
ones the
> same way before you put them on the car.
> 
> Let us know what you find.
> 
> Walt Tampa, FL