The working temperature of your
is normally kept to an optimum level
. But there are occasions when your engine is worked
harder and reaches temperatures higher than normal. This can happen, for
example, when you are towing a trailer or another vehicle, or if your engine
has been tuned for higher performance.
As the temperature of your engine increases, the engine oil becomes thinner
and thinner. If the engine is run above normal temperature for a long time,
there is a danger that the oil may become so thin that it can no longer
lubricate the moving parts of the engine properly.
If this happens your engine can become seriously damaged to the point where
it has to be stripped and rebuilt or replaced completely.
While a water
gives a fairly accurate reading of the
engine temperature via the cooling system, it does not directly tell you much
about the temperature of the engine oil. For this you need a special oil
These gauges measure the oil temperature with a sender unit, similar to that
used for water gauges, which
directly into the
to give an
accurate reading of the temperature.
The gauges are available from accessory shops and are either mechanically or
Fitting an oil pressure gauge
The gauges are mounted either directly into the
or in a bracket
suspended under the dash.
How the sender unit is fitted into the sump pan depends on the type of gauge
you have and the model of your car. In some cases the sump pan will have to be
removed and a hole drilled and tapped with a thread to accept an adapter.
Other types use the drain plug in the sump as the fitting position for the
sender unit. Again you may need an adapter to fit the sender.
Reading an oil gauge
How you should interpret the readings on an oil temperature gauge
depends to some degree on the model of your car. But, as a rough guide for
a 2-litre engine when it has been running for some time, the following
- This is a normal oil temperature for an
engine under not too much load.
This is a normal reading if the engine is
working particularly hard, for example when towing. Above 110°C The oil
starts to thin out seriously and lose its ability to lubricate the engine
and dissipate heat from components. Check the level of the engine oil and
inspect the sump pan to make sure it is not covered with heavy deposits of
It is rare for the oil to run too cold, but
this can happen with cars fitted with an
. If the temperature
drops below 70°C suspect a faulty oil cooler
Note that all engines, whether or not they are fitted with an oil
cooler, are prone to low oil temperature in cold weather, even though the
water temperature reads normal.
Drilling a sump hole
With some kits you have to drill an extra hole in the sump casing to fit
the temperature sender unit. Check with your dealer first, or the gauge
manufacturers, to find out where such a hole can safely be drilled.
Drain the engine oil and remove the sump casing from the engine. Mark
and drill the hole in the required position.
Solder the adapter provided in the kit into position in the hole. Make
sure all metal flakes from the drilling have been removed before refitting
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There are two main types of oil seal: static and dynamic. A static oil seal fits between two non-moving parts, a dynamic oil seal between a stationary part and a moving one. Most oil seals are made of synthetic rubber.