Reintroducing a Thermostat

As I am not happy with how the cooling system is working (over-cooling) I am going to re-introduce a thermostat.  One option is to add a lower water rail and connect this to the bypass outlet of the thermostat housing.  Only problem with this is that the sensor for the coolant temperature is mounted in the main cooling pipe and would not read properly, especially during warm up.  I've read that the thermostat housing can be drilled and tapped so that the sensor can be mounted here, but I don't want to take a chance trying to do that with something made of plastic.

In the end I've gone for the option some other Tiger owners have adopted: a thermostat with a bypass hole for the warm-up phase.  I've used a 88oC thermostat from a Ford Focus 1.8 diesel (part # QTH316K).  Prior to fitting a 4mm hole was drilled through the outer edge.

The Tiger provided radiator fan switch was a 87oC type, so that was changed for one that operates at 92oC (Intermotor part 50200, used on Alfa 33's, Audi 80's, etc.).  I took the car out for a spirited drive yesterday afternoon.  55 miles approximately.  Once warmed up the coolant stayed very steady at 88oC.  When I stopped in traffic it rose to 92oC, at which point the fan was running.

So far I am very pleased.  I'd just like to test the car in colder and warmer conditions, with a bit of time stationary to make sure it's not going to get too hot.  I've got the temperature warning light on the Acewell digital dash set to 95oC so that should alert me if there is a problem.  There's also a coolant overheat warning displayed by the ECU warning light.  This is via the temperature sensor that is screwed into the engine block.  I don't recall at what temperature this activates.

During this whole process one thought did occur to me: if your car does not have a coolant warning light it would be easy to add one by using the second (higher) temperature setting on a dual-temperature radiator fan switch.

Updating the Dash Warning Lights

There are two warning lights wired into the Webcon loom: one for the RPM warning (shift light) and another for the ECU (warns of Throttle Position Sensor error or coolant overheat).  I'd always wanted to put these on the dash where I could see them.  Only problem is both are just plain red lights, and I didn't want to stick labels on the dash.  In the end I came up with a solution: 3mm Letraset and spray enamel.

The best method seemed to be to apply the letters to the warning light and then to add one quite thick coat of enamel.  Just enough so that it did not drip.  I tried two coats on another light and the second coat melted the first and it looked a mess.  Also I found that the Letraset had to be rubbed very well onto the light or the enamel would lift the areas of Letraset not properly in contact with the warning light surface.

Here is the end result, all four key warning lights right in my field of vision, or peripheral vision if I am looking at the road.

The dash doesn't look this scratched in real life.  Its the camera flash that seems to be very unflattering.

The alternator warning light was the original from Tiger.  I didn't have this fitted originally as I was planning to use the low voltage warning on the Acewell digital dash, but I hadn't realised that the alternator will not charge the battery unless the warning light is in the circuit.

The oil pressure light was added to replace the one on the Acewell.  I was not happy with the Acewell one as it was fairly small and partially hidden behind the indicator stalk.  I wanted this important warning light right where I could see it.  Only problem was they are only available in yellow.  Any production car has them in red, and so they should be as this is a warning as opposed to a caution.  My solution was to get a blank red warning light and add the word 'OIL' myself.

Alternator Problem Solved

I didn't have a charge indicator light for the dashboard (digital dash has a voltmeter and a low/high voltage light).  Without this in the circuit the rectifier in the alternator does not send a charge to the battery.

With the light connected the alternator worked perfectly.  It's nice when problems are fixed easily (and cheaply).

Here is another video of the car running.  Apologies for the terrible sound quality from the mobile phone.  It is much, much better in real life.