Removing the sump pan can involve removing or raising the engine. If so the repair is best left to a local main dealer. On certain cars it may also mean taking off the gearbox. If you are in any doubt, consult a dealer.
Removing, checking and refitting the pump
Put a tray or rag under the engine to collect any drips of oil, and unscrew the bolts securing the pump to the
As you withdraw the pump, mark the position of the pump
so it can be put back in exactly the same way.
The drive shaft sometimes drives the
as well (check in the service manual). On such engines, remove the
and mark the position of the rotor arm.
If the rotor arm is moved at any time — if the engine is turned, for example the
will have to be reset (See
Adjusting the static timing
On externally mounted pumps with a skew
, the gear can usually be put back in any position.
Use a rag dipped in petrol and, if necessary, a scraper tool to carefully remove dirt and any
remains from the pump mounting
Be careful not to damage the mounting faces on the pump or engine. Usually only externally mounted pumps have a gasket.
Run the engine very gently until the oil
builds up to normal, then check for oil leaks.
Checking an oil-pressure relief valve
The oil-pressure relief
is usually fitted in the oil-pump body, sometimes in the engine block.
The valve consists of a ball or plunger held by a spring. If the engine has low oil pressure (indicated by the
or oil-pressure warning light), the relief valve may not be seating properly. The cause may be a weak or broken relief spring, dirty engine oil or a worn oil pump.
Most valves can be removed, but some types cannot. Before attempting to check the valve, you may have to check its position in a service manual for the car or by asking your local dealer.
If the valve is inside the oil pump, remove the pump. Unscrew the plug that holds the relief valve in the oil-pump body or engine block, and remove the
and plunger or ball.
If the ball or plunger is stuck in the valve
, try to release it by gently prodding with a thin screwdriver. Be very careful not to scratch or damage anything particularly the valve bore. Scratches in the bore, ball or plunger will allow oil to
its way past the valve, which will lower the oil pressure.
Clean all the parts thoroughly in paraffin, white spirit or petrol, and check the valve ball or plunger for signs of a ridge caused by wear or pitting.
Check the spring to see if any of the
are cracked. To check it for weakness, compare its length with that of a new spring.
Using a lint-free rag dipped in paraffin or petrol, clean the valve bore, making sure any blockage or deposits are removed.
If any of the relief-valve parts are worn, throw them away and buy a new valve assembly.
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There are two main types of
: static and dynamic. A static oil
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.