Interested to get peoples experience here.
Head been off - new gasket / bolts and modular WP fitted.
Rad is a recore - 2015.
Rad has 2 push fans 6" and 10" both respond to fan stat soldered to edge of rad (on and off).
Fitted a new temp gauge as was concerned about 120+ 140 deg readings. Gauge is also voltage regulated.
It’s a worrying sight to see the gauge indication so high and recently added the supplemental fan to further assist cooling.
Checked the coolant which was a bit low so added more and ran with cap off for a significant period and the water at the filling point is only tepid.
Using a laser temp measuring device the fans cut in at 86 and off at 80 deg approx with static testing. For 30 mins and does not boil or overheat as the measurement prove also and fans run and then switch off proving the temp does drop to allow fans to stop on thermostat switch.
Was thinking about tackling the radiator - but based on tests there is no need to - so leaving that alone.
Car has 88 deg stat in housing.
Have others had similar / same experience with high temp measurement at gauge - also replaced the sender unit for a like unit.
Just don’t want to be driving looking at a gauge reading of 120-140 nrly FSD of gauge when I know static running is between 80- and 86 Deg!!
Can anyone feedback with their experiences and running temps at gauge
TIA
Certainly sounds as if the gauge is incorrect. Remove the bulb end of the gauge
from the head, get a pot of boiling water and dip the bulb in. Should read 100 C.
Since you mention the gauge is voltage regulated, have you double checked with a multimeter?
The gauge should only be receiving 10 volts.
If it’s getting 12, then it will be over reading
it’s a smiths electronic resistance type with sender just below thermostat housing.
I did contact smiths as the car was like this when I got it (over temp on gauge) but no signs of overheating on car.
I did fit V/Reg to gauge (based on advice from smiths) and it still over read - Far as I know the B terminal is battery +
I terminal is instrument + feed & the VR needs a ground as does the gauge.
Im confident based on static measurements the rad is fine and the temp switch for the fans works as do the fans.
So it’s the VR or gauge wiring…
Now ordered another sender and VR in case and have a new spare gauge.
More testing which is awkward due to lack of space behind dash - which I’m sure is a story we al know to well.
Thanks for the comments and advice.
I even replaced the gauge and sender with a new Smiths Heritage set.
Finally I ended up ‘tuning’ the Heritage gauge with a resistor in series with the sender. I settled on 20 ohms to get the gauge midrange at cruising. The Heritage Gauge has a 90 degree mid-point. I used the same technique with the stock gauge and sender as well; from memory it was about 10 or 12 ohms to get a reasonable gauge reading.
The gauge now matches reasonably to heat gun readings and an icing thermometer placed directly in the coolant next to the sender (I have a cap style thermostat housing).
Way less anxiety, and the gauge now tracks very well with the electric fan coming on and off at idle.
The resistors look like this and are readily available on eBay in various values. Some come with wires that just need crimped-on spade connectors. These ones need wire soldered on.
Your car and it is easy to get confused with what the actual temperature is rather than various measurements, but I think your fan cutout range sounds low. Ignore my concern if the temperature gradually rises at idle, the fans come on, which kicks it back to ‘normal’ in about three to five minutes.
new VR and I even have a spare smiths gauge which sounds the same as yours.
Thanks for the detail - I’ll do some tests on the output of the sender resistance output & temp and also check the Ohms across the gauge as well as the VR output.
So a little work to do for now.
I’ll look at the suggestion to get things more in line if I can’t resolve with the aforementioned.
Thanks for taking the time to prove the detail - very helpful thank you
To check the gauge is correct for your car, look under the wordTEMP and you should find a code. The following site used to have the codes on there under Lotus
I’ve jerry rigged a unit with a digital VR <5 quid - therefore cheaper than the VR units sold for gauges- it’s also adjustable output as well.
So done testing today and now have a good correlation from the laser measurement and gauge reading. with a gauge feed of 10V
So will wire that into the temperature circuit tmrw and test - but I now know I won’t see the gauge at 130deg with the engine at 95deg ish - as it’s intuitive to worry when your looking at it whilst driving and those niggles don’t help when seeing the needle indicating 120+
