Vauxhall Corsa D: Oil Pressure Switch Replacement

Also known as "My Vauxhall Corsa D is leaking oil from top left hand side of the engine", the Vauxhall (or in some markets, Opel) Corsa D has a known issue with it's Oil Pressure Switch failing.

After some use, they eventually fail and start to leak oil inside your engine compartment - worse, some of this oil can get pushed back into the wiring, and then drawn up into the loom via capillary action - left long enough, a failure of this switch will be followed by failed lambda sensors, airflow sensors and then ultimately, the ECU.

The part is cheap and simple to replace, it really is 10 minutes work.

Make sure you give your car time to cool down first though, you're going to be working in close proximity to the manifold - when that's at temperature it'll happily sear the flesh off your hands.

For those who prefer it, there's a video version at the bottom of the page.

 

You will need

  • 24mm Ring spanner or adjustable spanner. Some may reportedly be 22mm
  • Rags/kitchen roll
  • Replacement Oil Pressure Switch

A new switch can be as little as £5. However,  I ordered a slightly more expensive (£10 at time of writing) Febi Bilstein one for a couple of reasons

  • Febi Bilstein is a brand I know, rather than one I don't - I've more trust that the switch won't fail a few weeks later
  • The Febi Bilstein switch has an absorber/damping layer as part of it's seal which should help protect from similar failures

For the sake of £5 it seemed better not to risk an unknown brand.

 

Procedure

You'll find you pressure switch on the top left of your block, most likely (as pictured) with signs of the oil leakage all around it.

Vauxhall Corsa D Failed Oil Pressure Switch

As manky as the fitting may look, the other side of the switch is wet, so you won't need too much force to get it undone - resist the temptation to put a deep socket on it, it's not worth risking ruining the threads.

The connector has a clip on it - it's not visible in the picture because it's on the underside of the switch, but it's fairly sizeable, you should easily be able to undo it by feel alone - just lift the clip away from the switch slightly and the connector will slide off.

Use your ring spanner, or adjustable spanner to turn the switch anti-clockwise (also known as left-loosey) slightly. 

Once you've got it moving, you should be able to twiddle it undone with your fingers

When it comes out, you'll probably find that it's fairly gunked, with oil in the section the connector had been inhabiting

Old Oil Pressure Switch wet-sideOld Oil Pressure Switch Oil connector receptor

The connector itself will probably also be quite well coated with oil, use some kitchen oil or rag to clean it.

Oil Pressure Switch connector needs cleaning

Resist the temptation to use anything like brake cleaner to help clean - whilst it'll lift the oil away, the residue it leaves will also attack the insulation of the wiring, weakening it over time. Short of replacing the loom, or paying Vauxhall for an expensive loom cleaning, there's very little you can do about any oil that's already made it into the wiring harness.

Remove your new switch from it's box, and carefully screw it into place - be patient and extremely careful not to cross-thread it - stripping threads will lead to needing some expensive work to get your car moving again.

Once the switch is finger-tight, use your spanner to tighten it by about another 1/2 turn - you obviously don't want it to be able to vibrate itself back out.

Reconnect the wiring connector

New Oil Pressure Switch installed

To finish up, you'll need to do some or all of the following

  • Use rags to clean up oil residue from the leak (particularly any pooled on the PS pump, as in the picture above)
  • top your oil back up to replace that which was lost, or
  • take the opportunity to do an oil and filter change

Once those tasks are done, you need to let the engine run until it warms up to normal running temperature and visually check for any signs of leaking around the switch (and of course, the filter housing if you did a full change). Then turn the engine off, let the car sit for 5 minutes and then check the oil level on the dipstick - top up as necessary,

Video

 
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