Monitoring engine performance while traveling far from home is a good idea. Twice I learnt the hard way. the first occasion was when my oil pump failed in central Botswana on the return leg after two weeks in the bush; and the second was a blocked air filter when a gauge monitoring the exhaust gas temperatures would have prevented a damaged turbo.
Exhaust Gas Thermometer (EGT)
Monitoring the temperature of the exhaust gases (EGT) is highly recommended for all turbo-diesel vehicles, especially pre 2005 models. When the exhaust gas temperature exceeds 700°C turbo damage results within a short time. causes of high EGT are: high fuel-air mixture, blocked air filter and pushing the turbo-diesel too hard. In this way the gauge indicates that damage is being done to the engine. It also indicates if the engine is being driven too hard, for example towing up a long hill on a hot day. without such a gauge the driver towing up a long hill on a hot day. Without such a gauge the driver would press on regardless, with the gauge warning, a lighter right foot could prevent engine damage. I highly recommend this gauge, especially if you use your turbo-diesel to low. I bet, in five out of ten cases, an EGT gauge will prevent a huge repair bill.
Oil pressure gauge
The signal is transmitted to the gauge via either an electrical sender unit or thin copper tubing that carries the oil to the gauge. in general, the latter type is more accurate and reacts faster to pressure changes. The electrical gauge is more common in newer vehicles.
Oil temperature Gauge
The signal is transmitted to the gauge via an electrical sender unit. This gauge is an essential item when traversing heavy sand or towing, Know the safe maximum oil temperature for your vehicle and never exceed it. 120°C is the maximum for most vehicles.
This gauge monitors the condition of the battery. Voltage measurements must be taken with the engine turned off and some electrical equipment switches on e.g. park lights. Only when the battery is working can voltmeter indicate how much more work the battery is capable of doing. This is because it is the voltage drop that determines the condition of a battery. For example, a battery with nothing switches on may indicate 13 volts. If, when lights are turned on, the voltage drops to 10 volts, this indicates a battery in a poor state or one that is old or damaged. If the voltage stays above 12-volts, this can be regarded as normal and the battery in good condition. The higher the load on the battery, the higher the voltage drop will be.
The ammeter measures the flow of current in and out of the battery. Vehicle ammeters have a central indicator that swings to either negative or positive. It is wired to enable a vehicle operator to determine if the load on the battery by electrical equipment is higher or lower than the amount of current the alternator in returning to the battery. For example: If the lights are turned on with no engine running, the indicator will swing to the left or negative. When the engine is started and the alternator engages, the indicator will swing to the right, or positive. If you find that you ammeter tends to run towards the negative when running electrical equipment, then you need a heavy-duty alternator.