Water Temp Warning Light Sender?

Chris Duncan

Supporter
I have a water temp warning (overheat) light on the dash but can't find a proper sender.

The intake manifold has a 3/8" pipe thread and can be adapted to 1/4" or 1/8" pipe. It has about 1-1/4" clearance above.

Don't know what temp a warning light like this should come on but the one supplied by the local auto parts store comes on about 100deg which is way off. Must be some kind of EFI sensor. Thinking about 215deg F.

Any recommendations? Year make model engine? Part no.?
 

Dimi Terleckyj

Lifetime Supporter
Hi Kalun

Usually the temp warning light is used to warn of the temp getting much higher than normal or when the system is close to boiling.

This temp will be decided by a number of factors;

How your cooling system is set up.
The normal temp your system runs at.
The temp or point that you would like to be warned at.

EG;

If your system boils at 225 but normally runs at 180 to no higher than 210 then set your warning at 215 or whatever temp you want it to come on at before it reaches boiling.

Usually a temp that you will have enough time to shut the engine down without sustaining any damage.

The easiest way to do this is with a thermal switch such as an adjustable electric fan switch used with electric cooling radiator fans.

These switches are available at all parts stores as a spare part and as they are adjustable you can just dial in the switch temp as you want.

I use one of these switches to control my electric fans on my radiator in my 40.

As well as switching a warning light it is advisable to have it switch a small warning buzzer as you may not notice the light on bright sunny days or when you are pre occupied with some thing else.

Dimi
 
Kalun

You are using an EFI system from memory.
Program it to turn on the light at a set threshold.

A good system will be able to do this and shut the eng down if that is required.

Jim
 
Kalun, is that 100 celcius perhaps? 100 celcius is around 230F I think, and, right at the boiling point for water in an unpressurized system. If you're running a 11psi cap then you'll still have some room to spare.

I have a water temp light that come on at 80 celcius (about 190F) - the light is a helpful reminder that the system is getting warm and it's time to turn on the fans manually (if the automatic switch isn't working). It seems to be a helpful/useful set up like this.
 

Chris Duncan

Supporter
The Gen7 ECU has one water temp controlled output that turns the rad cooling fan on and off.

It has another AUX output that can be switched between a shift light and a 2nd temp controlled output. I have it set to a shift light, so would have to disable that to run it as a water temp warning light. May temporarily do that for now.

so still need a water temp sensor for a overheat warning light.

so still looking for recommendations for a sender with 1/8", 1/4", or 3/8" pipe with 1-1/4" clearance above (from manifold surface), and about a 215-F setting.

I'll be looking at the settable sender that Dimi mentions also.
 
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