2006 Mk2 1.6 Petrol LX Oil light on when at idle

[cdavies2411]

Hi Everyone,

I have a 2006 Mk2 Petrol (LX) Focus with 102,000 miles on the clock. After a motorway run the other day, I slowed to idle at traffic lights and my oil light came on. We checked the oil and it was very low. (It had recently ran very low in what felt like a short space of time, so initially we suspected leak etc.) After a small top up, the light seemed to pass and when checking it at our final stop, the oil was now above the max line...

Since then, the oil light has begun to come on again, but only at idle (750rpm-1000rpm, tending toward the 750). As soon as I accelerate, the oil light turns off - only to come back on again when the engine idles. No sign whatsoever of the oil level falling.

I'm reading lots of scare stories about bearings and crankshafts, so I was wondering if anyone's had a similar experience, knows of a range of potential issues that it may be or even has an idea of a UK cost of a repair (lots of Americans shouting $2.5k)?

For a bit of context, it's always had a rattle at the top end but no mechanic we've talked to has been concerned by that; I had an MOT a day before the problem started (no service, filled it with new oil after it ran very low), we did contemplate another change and an oil filter change - but I'm thinking hold off until a garage has had a look?

Any thoughts at all would be greatly appreciated!

Thanks in advance for your help!

Chris

[dezwez]

you may have a faulty pressure switch not much to replace 😊

[isetta]

of course faulty switch would be best outcome but I would not get too hopeful about that, but it might be that

I had a Triumph TR7 where the oil pressure light came on at low revs and that was because the end of the spring in the pressure relief valve had broken off leaving the pressure relief valve open slightly. Luckily a relatively easy job on a TR7 as the oil pump with the valve within it is bolted onto the outside of engine block, which is a strange arrangement.

My brother's Audi TT had oil pressure light coming on and that was fixed by replacing the oil filter. He had the car from new and the oil had not been changed for at least 10 years. It was all clogged up with like granular black  carbon stuff.

No idea where pressure relief valve might be on your engine - but it might not be that either.

[cdavies2411]

Hello All,

Here with an update! I did an engine flush using Wynne's Engine Flush, then an oil change, added some Wynne's supercharge oil treatment and replaced the oil filter and it seems to have fixed the problem - no more oil light on when idling and if I don't come back with a further update, assume that's the end of it haha!

Going to change it every 6 months now that we've hit 100,000 miles and hope it holds on!

Thanks for your help!

Chris

[dezwez]

14 minutes ago, cdavies2411 said:

Hello All,

Here with an update! I did an engine flush using Wynne's Engine Flush, then an oil change, added some Wynne's supercharge oil treatment and replaced the oil filter and it seems to have fixed the problem - no more oil light on when idling and if I don't come back with a further update, assume that's the end of it haha!

Going to change it every 6 months now that we've hit 100,000 miles and hope it holds on!

Thanks for your help!

Chris

good luck 🙂

[Botus]

my one did this all of a sudden after changing oil and filter....   and at the time I thought something odd happened / broke when the oil filter came off, as all of a sudden a second stream of oil far larger than I'd ever seen before or since burst out from the filter housing - and this was exceptionally hot (double what I'd expect … and used to be a tech, so done it a few times)....    then when I restarted the oil light didn't go out... I thought no worries wait a bit, quite normal (even though I always top up the filter with clean oil before fitting) after 30 seconds I bottled it and turned off to double check (even though I knew I'd done everything right) of course nothing was amiss, so turned the thing on again, waited more than a minute and could hear the top end getting louder, still had the light on !!!

third time thought well if its had it, its had it, little to lose hold the revs up to 1600 and see what happens.... after 20 seconds the light was out and the top end went quiet.  Scratched head and went to read the internet...   LOTS of focus owners complaining and yet not one sensible reply I could find.  But a general theme.... it seems far more common on the ST models and a few say its the pressure relief valve sticking.

Tried a different filter the next day, seemed to help but was a short lived day dream.... Bought pressure switch made no difference, changed the oil and filter again made no difference.... took to a garage they shook their head and did nothing.

Reading the internet on 1.6 vvti  couldn't find anyone sensible saying if the pressure relive valve was accessible or serviceable.... went to ford dealer and asked questions.... looked at the part drawing.... got no sense from anyone...  So I told the main driver whenever you start as soon as it fires hold the revs up and wait till the light goes out.  Once out you could drop to idle and the light stayed out, and we used the car like this for 8 months !!!  Sometimes I cringed at how long it took to go out....

When the next major bit of work needed doing I thought I'll get them to take the sump off maybe the strainer is blocked coz my stupid sister used to run crap oil and drive to Scotland with nothing in it all too often.  But after 40k of me using proper oil it was clean as a whistle...   With the other work and the sump off, the garage said why don't we try a pump we're almost there. 

So genuine pump fitted (which is now modified and so needs different length bolts - which don't come with the pump - and weren't in stock !!! ),  With the new pump it was an instant cure... and the car's done 20k since, light goes off instantly.....    I got all the bits back coz I was interested in seeing what was wrong and so too was the garage who had already pulled it all to bits... What is clear as day, is the pressure relive valve is external and nothing whatsoever to do with the sump and (although a year on I've not bothered to play...) I guess is serviceable to some extent.  Was / is this stuck ? it behaved like it could be, I guess I'll never know.... (either way Ford only supply a pump, not spares - well that's what the parts guys deciphered from their systems and the drawing appeared to support them).  On the actual pump the gear and lobes all look to be almost brand new with little sign or wear for 120k miles.... but the faceplate has some fairly significant scoring on it... right where the oil could take a short cut back through the relief channel.  But I find it hard to believe its enough to cause no pressure at idle… unless the design is so bad they almost produce none at low revs from new (then its entirely possible and maybe why ST owners with brand new cars have the light on at tickover) !!!.