This is for a diesel engine generator that's going outside my workshop with remote start/control etc. I want to stop the engine automatically if it gets too hot or the oil pressure drops too far (a light or gauge is of little use if you're not there to watch it!).
Given that it's diesel & will run a touch cooler than most petrols I thought about using the fan switch from a petrol car to trip the fuel solenoid, if they switch at about 100degC that would'nt be far wrong I'm thinking.
Anywhere I can find out what temps they switch at? It's no good having it stop when it hits 90degC as that's within the range I'd expect to see & I'd want it a bit above the normal operating range. There are adjustable ones but they're a lot dearer than standard ones, & any I should avoid because they're known for failing? Mabye something from a Jap motor, never replaced one in them so they're likely good?!
Where would be a good place to site it? I'm thinking about turning an adaptor up to fit one in place of a core plug, then it'll read true engine temp & would still work if the coolant level dropped due to a leak.

hi
on some of the plant i work on
they put a relay in the solenoid feed
which is triggered by the oil pressure switch
the only down side is the engine wont start until you have oil pressure
the way they over-come this is by having a bypass button for starting or
another feed from the cranking position on the key switch to bypass the relay
obviously when the engine starts the key is released and the relay takes over
as for the temp cut out could you not use a kenlowe sender to operate the relay
cheers les g
ps something else you may like to think about some of our kit shuts down if it throws an alternator belt
yet again a relay tripped by the charge warning light not so essential but it all helps with unattended engines

As long as it operates before the engine boils, boiling point depends rad cap pressure but usually over 120c.

You really want a switch that goes to off at this temperature, the type of thing used to protect amplifiers --- very cheap off ebay or a couple of pounds from Maplin.

see ebay item 150409615219

I may have some in the workshop drawer but I would need to check the operating temp and if they are NC or NO type

Linky
You have to click on each one to see what temp the switch, but it's all there somewhere

Cheers fellas, that's all good stuff. Whether it's N/O or N/C is'nt a big deal, I could use a changeover relay to get what I want.

A few minutes & I've found this, 18mm thread so that's ok, temp just a bit above 100degC should be ideal!
http://partfinder.smpeurope.com/index.html?p=156&partid=50157&from=155

[Edited on 29/12/10 by hillbillyracer]

I always Like these for things like Fan Control use them in the Landy's

Super Doper Linky