temp alarm

[Simon Jones]

It's possible that the undoing / tightening of the screw on the temp gauge has snapped the wire on the back as the brass post rotated. Did that to mine once although in that case it read H as soon as the ignition was switched on.

[dreamwarrioruk]

the mason alarms been on for last 5 years working no problem, it reads temperature correct up to around 71 degrees and then if i speed up or as the engine warms up more the needle rises but doesnt drop back down until i turn off ignition. when i turn off it goes to about 11 oclock. turning engine back on goes to 12pm for a while then goes back up to around 1am. I cant work out if its physical or electrical. Just doing my head in for the last few weeks trying to suss it out. Think next step will be to remove mason and ground out the sensor wire to see if the gauge is getting a feed

[g8dhe]

You seem to be getting a range of symptoms, rather than just a slow creep upwards!
I think I would try to replace the sensor with a variable resistor whilst testing so you can vary the resistance whilst staying still in the drive!
Then you could ascertain what is going on by varying the resistance -temperature, not sure what the exact sensor values are but I think they have been mentioned previously - I would replace the sensor with a 1K Ohm variable and then see if the needle moves smoothly and if its stable over time. If it jerks about then that might indicate a problem with the gauge itself, but a slow creep would indicate electronics drifting.

[dreamwarrioruk]

Hi Geoff,
Thanks for that. It is baffling me, it behaves normal till I floor it then raises up in temp on the gauge but is reluctant to drop down, if I spin the needle manually to cold it lays to rest at 12pm, spin it to H and it rests back at 1-2pm. Could be actually behaving correct and we have an overheat but a thermal camera and the digital gauge dont give different readings, and all appears normal. Ive just ordered a tm1 kit so will put that in the mix. If all behaves then ill forget the temp gauge and rely on two digital gauges but im off to maplins in a minute anyway.

[g8dhe]

Just a thought, when you mention flooring it, I wonder if the regulation on your alternator is OK?
High rev's could be causing the alternator and hence the battery voltage to rise more than normal, it will then take a little while for the battery voltage to return to normal as well once the rev's have dropped, the higher voltage could then well be causing the anomalous readings.
Try measuring the battery voltage at rest, before starting the engine 12.6 volts would be normal, then when the engine is idling around 13.0-13.6 volts, and finally with the rev's much higher and heavy charging the voltage shouldn't exceed 14.4 volts.

[dreamwarrioruk]

hi geoff,
thats what i was thinking, just been out for a run, at rest bongo is 12.48v, idle is 13.82v and running at around 2000 rpm was giving out 14.38v. When cold the alternator doesn't sound healthy though.
Its not very straightforward for diagnosing it. Also as I returned the mason set at 4.5 bleeped with the gauge around 1 oclock something it hasnt done for a good 8 month. Getting annoyed.


Updateish.

Just been out to it semi warm, removed lead to new temp sender, gauge shot up to H with mason chirping away. Engine had cooled down, lower hose on rad soft and cold, saw and felt temp rise on radiator to the bottom then stat opened up and lower hose hot and rigid, metal pipe at bottom of thermostat housing now too hot to touch.
The whole thing is just like the needle on the temperature gauge had just jumped to the right a little bit as all else appears normal. confused.com

[dreamwarrioruk]

disconnected mason alarm for now and temperature while damped is working. engine temp monitor ordered so will move onto using that.

[dreamwarrioruk]

gonna put it down to the mason alarm being faulty. Got TM1 fitted today and Ive got 2 digital ones and thermal camera all reading same temps. At least tested the lca out as well when I sprung a leak on a coolant pipe. Ordered half a new set. I suppose its telling me its time for tlc.