Does your Temp Gauge do this

[pete1]

Hi,

I am trying to solve a "overheating" problem except the car doesn't overheat.I am pretty sure it is the Gauge but what i want to know is

Does your Gauge read a different reading when the engine is not running to when it is running both with the ignition on?

Mine drops about 10 to 15 degrees when the engine is off which i think is the amount i am "overheating" by but i don't know if this is normal or not

any help will be very much appreciated

Pete

[tattoodrob]

Hello mine goes up a few degrees when lights are on to when they are off.electrical fault but not too worried,maybe yours is electrical too...havent looked when engine started/off maybe someone can look and see if this is normal,im not driving mine for a few days otherwise i would look,rob

[pete1]

Thanks i just found that mine did the same,

I am changing the complete gauge and sender for a brand new one desinged to match from GreenGauges.

I hope a will have an accurate gauge at last, well for the temperature at least, the fuel level and speedo are still just dashboard prettiness

[stringbag]

Pete, they all do that. 14V when running, 12V when not means a little drop in indicated temp when you turn off the ignition.

What temp do your fans come on/off at? This will tell you what your guage should be reading (85 -90 ish when your fans come on).
If your guage reads much more than that when your fans come on, your guage is out of callibration.
Not a problem.
You can re callibrate your guage easily with a variable resistor, and you won't have to replace anything.

If you are going to re callibrate, there is a spare temp sender on the engine, at the front in the V, just behind the dizzy cap. It looks like a copper 2-3 mm round nipple about 10mm high and is much more sensitive and accurate than the standard one (which is just behind the dizzy body - one wire on a spade connector).
Just put the variable resistor in this line and turn it until you see the correct temp.
For the easy way, just use the temp at which the otter switch turns the fans on as a guide.
If you want to get it bang on, use a laser temp guage to check it as you go.

Ask Dave Beer, master of all griff cooling things, he has a wealth of knowlege on this subject.

[pete1]

Stringbag,

Thanks for the info, but my engine is a pre-serp and they only have the one sensor (as far as i can tell) just to the left of the dizzy, I was going to re-calibrate the guage but it seems to be inconsistently inaccurate, I have checked it several times using a calibrated thermocouple attached to a Maplin multimeter and even if i calibrate it i still wouldn't trust it.

If i change the Gauge i can get a sender that plugs straight in rather than neeeding a brass adapter, which i think will improve the accuracy a bit and be neater.