Radford_darren_5302 Posted October 5, 2017 Report Share Posted October 5, 2017 Good Morning, Couple of months ago I purchased a 1976 mark IV Spitfire. For the first part of ownership she ran perfectly with the temperature gauge never going passed half way. Recently however and for no reason I can see the temperature gauge just keeps climbing. I have flushed the system a few times. Replaced the thermostat and sensor. Changed the water pump and had the original radiator re-cored. Nothing seems to work. Just wondering if anyone has an idea of what I should do next? many thanks Darren Link to comment Share on other sites More sharing options...
Darren Groves Posted October 5, 2017 Report Share Posted October 5, 2017 Does the fuel gauge do something similar? They are both fed by a voltage stabiliser and when this goes faulty both gauges can get the full 12v rather than the 10v they need. If you have an original bi-metal one then orientation is important and make sure the gauge it's screwed to is earthed, the modern solid state versions are much more accurate and reliable. Does the engine seem too hot? If not it could also be faulty sender unit, there's plenty of rubbish/incorrect ones out there or cable to the gauge is earthing somewhere it shouldn't be. If you are certain the engine is actually running hot, then maybe an air lock if you've flushed the system, get the nose of the car in the air and run with the rad cap off this will encourage air out. Did the thermostat have a jiggle pin, if not drill a small hole to allow air past. Could also be running too lean or timing way out.... A few bits to start, others will have more ideas I'm sure. Darren Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 5, 2017 Report Share Posted October 5, 2017 Echo that, think darren has covered the regular failures Pete Link to comment Share on other sites More sharing options...
Radford_darren_5302 Posted October 5, 2017 Author Report Share Posted October 5, 2017 Thanks guys. The fuel sensor didn't work when I purchased the car then started working and when I stated her back up yesterday After the changes I the fuel gauge wasn't working. Could I ask how best to check the voltage stabiliser? Think you could be onto something there as I'm not so sure it's over heating but not wishing to take a chance I'm turning it off once the gauge gets to 3/4. thanks again Link to comment Share on other sites More sharing options...
Darren Groves Posted October 5, 2017 Report Share Posted October 5, 2017 The old style stabiliser switches volts on and off to achieve the correct output, so if you test with a multimeter the reading tends to ping up and down, but would give you some indication. I would be inclined to fit a solid state jobbie, they give a consistent 10v, they're normally under a tenner on eBay. Keep us posted. Darren Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 5, 2017 Report Share Posted October 5, 2017 We have had guys changing engines in the past because of mis reading gauges there, s many threads on here about the simple problem The VS is located on the back of the speedo and must be earthed to the body, generally a lead under a fixing screw/nut They give a pulsed 10.5 volts to keep the gauges reading consistently with ever changing car charge voltages, So you get 10- 0-10- 0 on a multimeter Solid state are available on ebay and some suppiers , roger added a cheap one on here a few daya ago Other things are having a non stabilsed sender which will also give hot reading Sender must be a GTR108 But as fuel and temp are misbehaving thebstabiliser is the common choice as culprit Pete Link to comment Share on other sites More sharing options...
Darren Groves Posted October 5, 2017 Report Share Posted October 5, 2017 I bought this one to fit on a friends car recently : http://r.ebay.com/Izc7O7 worked just fine. Darren Link to comment Share on other sites More sharing options...
Radford_darren_5302 Posted October 5, 2017 Author Report Share Posted October 5, 2017 Excellent thanks. Not had chance to fill diagnose but have noticed turning the lights on alters the temperature read out. If I turn them on and off a couple of times I can get the needle to move nicely... thanks for your help Link to comment Share on other sites More sharing options...
Radford_darren_5302 Posted October 6, 2017 Author Report Share Posted October 6, 2017 Good evening. Okay so I have been right through the cooling system and I believe that it is working As it should. The radiator appears warm at the top and cool at the bottom. With the cap off the water seems to be flowing. The temperature gauge still reads high but the engine I believe is not over heating. I then put a volt meter across the light green wire going the temperature gauge to ground. The reading was some what spermatic going from zero to 12v but not holding a value. Electrickery is not my strong suit.. I shall replace the voltage regulator and see if this solves my issue. Could I ask maybe a stupid question. How best is it to remove the speedo? many thanks Link to comment Share on other sites More sharing options...
dougbgt6 Posted October 6, 2017 Report Share Posted October 6, 2017 Removing the speedo? Presumably you want to get at the voltage stabiliser? Undo the centre console and let it dangle. You can get your hand in around the back of the speedo, I think the nut is knurled, mine was anyway. Easy to get off and if you replace with an electronic one, no need to strap it to the speedo, it is very light and can dangle behind the dash. Link to comment Share on other sites More sharing options...
Radford_darren_5302 Posted October 7, 2017 Author Report Share Posted October 7, 2017 Thanks Doug yeah wish to replace the voltage regulator Link to comment Share on other sites More sharing options...
Gully Posted October 7, 2017 Report Share Posted October 7, 2017 Yes, when you remove the centre console you should see the existing voltage stabiliser attached to the back of the speedo. I attached the new solid state one to the nearest knurled nut speedo clamp, which also happens to hold the speedo earth wire. Gully Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 16, 2017 Report Share Posted October 16, 2017 And a small hex key to undo the heater knob retaing screws Pete Link to comment Share on other sites More sharing options...
Radford_darren_5302 Posted October 16, 2017 Author Report Share Posted October 16, 2017 thank you guys for your input. The car runs fine now with its new voltage regulator and various other components. thanks again Darren 1 1 Link to comment Share on other sites More sharing options...
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