Mondeo Mk3 oil pressure sensor replace

Disclaimer: I am a complete amateur at this stuff. Please do your own research and use your own common sense. I'm not responsible for any damage you do to yourself or to your car. I'm just sharing my own experiences here for the hell of it :)

My Mondeo Mk3 is such a well behaved, polite old girl… she always waits until I have finished up on a contract before telling me there is something wrong. Last year the ignition coil pack died just two days after contract end, and this year the same immaculate timing but with an apparent oil pressure issue; the low pressure light suddenly came on while driving along and despite having plenty of oil in the engine.

A quick search for possible causes included:

1.  Of course… low oil. Nope! I also visually checked the top of the engine through the filler cap and everything was well coated in oil. Engine sounded fine too.
2.  Faulty oil pump. Likely need to remove engine to fix.  Please God no…
3.  Faulty pressure relief valve. I’d have to take the inlet manifold off all over again. Please God no…
4.  Faulty pressure sensor. Easy and cheap to fix. Please let it be this!

The inimitable and over-caffeinated (?) American, Scotty Kilmer, has a rocking video on pressure switch replacement on a Honda. So consider this a quiet Englishman’s equivalent for a Mondeo Mk3 and go pour yourself a nice cup of tea and put a little Mozart on… okay?

The pressure switch is easily accessible and is situated just to the right of, and above, the oil filter. Here it is shown with the connector already removed...

You will need a deep 21mm socket to remove this... I was lucky enough to already have a 21mm spark plug socket that fitted very well. I changed my oil and filter at the same time but you could change just the switch if you wanted to… you will lose a little oil in the process of course.

The replacement sensor/switch I bought was made by “ERA” and is part number 330029. This one has some solid red sealant on the threads, but if you get one that doesn’t have this I am told that you should put some high temperature silicone sealant on the threads before fitting it.

I also cut a millimetre or two of the green plastic off of mine so that the socket fitted onto it better...

Clumsily, I managed to round off the sump plug even more than it already was when I was taking that off…

So I put a new one of those on too. That was part number 333590091, made by “Guide Pro”, and it has a M14 x 1.5 thread with a 13mm nut. Use a ½ inch socket on it though for a tighter grip but, yes, it’s easy to round it off if you’re not careful!

I treated myself to a low range torque wrench (5 to 25 Nm) for this job as I do have a tendency to want to overtighten things. This piece of kit covered both the pressure switch (15Nm) and the sump plug (28Nm) nicely…

Here’s the new pressure sensor/switch and oil filter fitted…

And the good news is that the oil warning light is now staying off. Yay!