318 Glow plug problem?

For quite some time I've had the glow plug light stay on after the engine has started.
Last major service in Hallam, noted the problem, but no explanation.

During that service, there was a transmission vibration. They suspected the convertor.
During the service they found a cracked transmission mount which was replaced, however, they still wanted to check the convertor. The vibration disappeared without checking the convertor, so I'm now reluctant to use the same authorised repairer without diagnosing the cause of the problem myself.

I now have a very annoying beeping sound when I start moving the van on an incline and turning corners, while still cold. Once warmed up, and for the rest of the day, no more beeping.

I want to use the "machine that goes bing" before I take the 318 to a mechanic and/or stealership to have the airbag replaced.

I have read the glow plug module could be the problem, along with one or two glow plugs being the problem, along with problems of removing them.

At the moment, the 318 has no problems in starting.

So I'm after suggestions and ideas of what and how to check, and also where I can buy the right "machine that goes bing".

I found the ding, ding noise was related to the coolant header tank. Topping up the coolant removed the constant ding ding sound.
On the 24/4/19 while driving down a heavily corrugated road to a chook farm the ding ding noise started again permanently, and the low coolant light came on.
Topping up the coolant level made no difference. So I was sure the low coolant sensor was buggered.
Last Thursday with the help of Eric and Owner, Owner successfully connected up Erics computer.
We found 3 glow plugs are open circuit, which I can live with, however, there was no fault showing low coolant.
I grabbed the header tank off my old 315 and drove home with the stereo up loud to help keep my sanity.
Yesterday I filled up the 315 header tank with water and plugged it into the wiring loom and "Bingo", no more ding ding.
I found the electric sensor is easily removed by a quarter turn with no loss of coolant.
So I swapped the sensor over, only to still get the ding ding. I then fiited the 318 sensor into the loose 315 filled header tank and ding ding gone.
The cause of the problem was the float in the header tank. I then swapped over the header tanks and now have no ding ding.

Just looked up my parts manual. What I called the header tank is called the Coolant Recovery Bottle

Now that my sanity is no longer under threat, I thought it would best share the cause of this problem with all NCV3 owners.

Sockeye,

Another reason for false alarms on the low coolant level sensor is a low concentration of anti-freeze.

The float on the sensor is made from expanded or aerated plastic which has a density very similar to tap water. Anti-freeze is heavier that water hence with a 50:50 concentration the float floats! If your anti-freeze concentration falls then the float may not float!

Check the concentration of your anti-freeze mixture with a hydrometer and correct if necessary.

Keith.

To test the electric sensors, I used tap water, which floated the float in the 315 bottle.

After removing and emptying the 318 bottle, I found the float freely rattling around the bottle.