Topic

I took the MGF (2001 Mk 2) for a run last night and noticed the coolant temperature gauge not registering. Investigation showed that, when I turn on the ignition, the needle goes from zero down slightly, then doesn't move.
Checking via OBD2, the coolant was running between 88C and 90C consistently during the trip (approx 100km each way).
There has been no previous issues, and I have not had a chance to check connections around the engine.
Any suggestions before I start?

Just check coolant temperature gauge sensor on the engine elbow. Most probably needs change and that is all.
Be warned that on the elbow you have two sensors. The sensor with only one wire is the gauge sensor. The other one is engine ECU sensor.

Good advice above.
In addition, that temperature range seems low, perhaps you need to check your thermostat?

Thanks David. I wondered about that. The engine has recently been replaced, and the temperature gauge, when working, always sat just below half way - never moved. I will check the thermostat once I get this problem sorted.

As above, check the blue coolant temp sensor. A quick test is to earth the lead to the sensor, the gauge should go to the top.

88 - 90' is fine if you are cruising, stationary or slow traffic should give slightly higher temps.

Thanks everyone. I got into it today, and found the wire to the sensor was broken right where it enters the sensor. A bit of fabrication, and everything is fine again.

Good to hear.

On the subject of coolant temperatures, I monitored my readings while doing a bit of shopping, town, commuting, A roads etc.
Once fully warm, the coolant only varied between 98 and 104. So either my engine runs hot or yours runs cold.

Mine is more or less constant 98 whilst rolling, at idle of very low speeds it can get to 106 then the rad fan(s) kick in.

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David Aiketgate wrote: wrote:

......Once fully warm, the coolant only varied between 98 and 104. So either my engine runs hot or yours runs cold.

You're a tad hot David.

talkingcars wrote: wrote:

David Aiketgate wrote: wrote:

......Once fully warm, the coolant only varied between 98 and 104. So either my engine runs hot or yours runs cold.

You're a tad hot David.

Why, thank you James...

The problems with gauges are, that in order to take their readings as gospel;
Firstly, the gauges and senders need to be of high quality (not likely with any OEM equipment)
Secondly, they need to be calibrated on a regular basis.

Not that is to say that they are useless, far from it.
Where they are useful is a comparator over time, don't worry about the indicated numbers, but watch for differences in the readings over a period of time and also look for any sudden changes which may indicate potential inimate catastrophic failure.

Get to know where the needles normally sit on your individual car, and investigate any unusual readings ASAP.
Gauges give you a chance to head problems off as the pass, by demostrating unusual behaviour, whereas idiot lights may only inform you after the damage is done.
As always........trust but verify!

Good advice Cobber.

John