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temp problem


bengaku

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Quick question i have just got a 76 spitfire really nice condition got  a new MOT and took it out today for a wee drive got to a car park and was showing a guy the car lifted bonnet and notice water dripping from the little rubber pipe running from top of engine to radiator also saw that temperature gauge in car was at the H .now car was running ok on the drive including a short way on the motorway. So is it just a case of tightening up the clamp as it does appear to be dripping out at the point where the clamp is and will also will refill radiator with coolant .or is it maybe require further investigation. Thanks for looking regards Paul 

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Update i tightened up the clamp on the hose leading from the thermostat housing to the top of radiator. Car no longer leaking but it is still running hot after only about a ten minute drive the dash thermometer needle was right on the H .so im thinking the thermostat is faulty ? But if any one has another suggestion let me know thanks for looking 

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There is an identical looking temperature sender/sensor that is often supplied as it "fits" out cars, but reads too high. 

Does the radiator slowly get warm, and then suddenly go hot? That is what happens when a thermostat is working correctly.

And you can check the thermostat. Remove it, and put it in a pan of boiling water. It should fully open, and then as then close as the water cools. The thermometer should also have the temp it opens at stamped on it somewhere (hopefully 82 degrees, 88 is a bit high but was often fitted for winter use). You could refit the thermostat housing without thermostat and see what happens then. However the recent drop in ambient temps will make comparisons difficult!

Ideally you want to know what the actual temperature is. A while ago I bought one of these http://www.ebay.co.uk/itm/DIGITAL-DISPLAY-FRIDGE-FREEZER-PROBE-THERMOMETER-TEMPERATURE-GAUGE-METER-IPk-/232486021979?var=&hash=item36213f2b5b:m:m07HHDgA0A0jh81yhQimpeg for a similar reason. It was less that 1/2 degree out in boiling water, and I reckon the probe could be fitted into the top hose if you release the hose clamp. It may leak a little, but would be ideal for testing purposes.£2 well spent! Plus handy for checking the fridge and freezer temps to at home.

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Yeah it's £7.45 for a thermostat and new gasket and once I take off housing to check thermostat makes sense to just get a new one and if it doesn't Solve problemat least I have a new thermostat and gasket.see what happens can't work on car this weekend so will look at it on Tuesday 

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  • 2 weeks later...

Update changed over to a new thermostat and gasket but temp gauge still runs up to the H the engine is hot the radiator top sides and bottom are hot both top  and bottom hoses are hot so any ideas would be greatly appreciated thanks for looking 

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The hoses will be hot, even with the thermostat opening correctly. But really you need an actual temperature reading to see how hot.

Is water getting past the rad cap? Is the engine fitted with the fan on the water pump or does it have an electric fan (or both?)

If it really is hot (not yet established) the problem may be a blocked rad. It may flush out, or may require a recore. But you need to confirm the actual temperature, he std gauge may not be giving a true reading.

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Open the centre of the dashboard and use a voltmeter to check the supply voltage to the temperature gauge (light green wire on my GT6). It should be 10v - if you have 12v then the gauge will over-read with the correct temperature sender. The 10v is a stabilised supply via a little box on the back of the speedo. If that is correct, then try changing the sender as suggested above to ensure you do have a GTR108 fitted. I had a similar issue earlier in the summer - there is a thread on here tracking my progress to resolving it!

Gully

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It can still be the stabiliser, these gauges are a simple bi metal spring wound with aheating coil, if they used the cars variable voltage 

With will range from 11 to 14.5 volts they woul always be giving wildly differing readings throughoutba journey, the small stabilliser gives a constant pulsed 10.5 volts so the gauges keep consistent readings,  both fuel andntemp use this supply

This is why a duff unit will vive high readings for temp or fuel   regardless of the signal its being sent.

A failed temp transmitter or an incorrect one will give high reading or none at allT

Temp senders are GTR108 and stabilser for a late spit is 148876   available from most suppliers get both if you are unsure  always useful in the spares box

On ebay and some is a modern electronic stabilser unit that many use 

It must be a stabised supply not just a dropper

Pete

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Hello All 

              I just use one of these inside the old metal can(cheap as chips) and not worked hard by our gauges.

http://www.ebay.co.uk/itm/L7810-CV-Positive-Voltage-Regulator-IC-/401349119282?var=&hash=item5d72458d32:m:mpY0WRfRJcdPLwUbrDUX8bw

 

The one in Spitty must be  5 years old by now!

Roger

Ps buy 5  only 40p more and if you blow one up plenty of spares

Edited by rogerguzzi
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