Punto (Mk2/2b) oil warning light flashes (or on) randomly

[Stephen505]

Hi, I am quite worried with my Fiat Punto Mark 2 (1999-2000 model) with 72000miles of mileage.

I have just cashed out some 900Eur on rust and breaks and now just after I took it out from the sprayer, I have noticed that the oil warning light flashes on/off. More precisely, initially it is off, then after 2mins driving it flashes on but it goes away when pressing the accalerator and this keeps for a while (5mins or so) until then it remain on all the time until the car is power off.

So I replaced the oil (but not the oil filter as it was hard to remove with my bare hands) and the problem persisted. The fuel consumption is still normal 42-44mpg as if there is no load on the engine and there is no strange noise from the engine - it >>SEEMSS< that it works normally. One thing - when I took the acr from the sprayer (rust problem on roof) the car was reseted (clock different time, tune lost station presets, odometer 0miles) - why i never guessed?


Can a 'very dirty' oil filter cause this problem? Could it be the cap of the oil inlet (its a bit torn out)? If electronic fault would removing the battery from the car for a while help (a raw kind of reset)? What could be other problems?

 

[s and b]

i would certainly be changing the oil filter
remember if your not bothered about the mess hammer a screwdriver through it to get it going so you can swing on the screwdriver handle
report back when youve done this
dont drive the car

 

[jon1612]

i would certainly be changing the oil filter
remember if your not bothered about the mess hammer a screwdriver through it to get it going so you can swing on the screwdriver handle
report back when youve done this
dont drive the car

going back a few years this was always a sign of a faulty oil pressure switch, as s and b said change the oil and filter first then i would change the oil pressure switch if you still having a problem, they only cost a couple of quid if you still having problems after that you need to start looking at the oil pump but think those few steps will sort it

 

[atom0007]

Hi, I am quite worried with my Fiat Punto Mark 2 (1999-2000 model) with 72000miles of mileage.

I have just cashed out some 900Eur on rust and breaks

Ouch

 

[varesecrazy]

Hi,

I have just cashed out some 900Eur on rust and breaks and now just after I took it out from the sprayer, I have noticed that the oil warning light flashes on/off. More precisely, initially it is off, then after 2mins driving it flashes on but it goes away when pressing the accalerator and this keeps for a while (5mins or so) until then it remain on all the time until the car is power off.
One thing - when I took the acr from the sprayer (rust problem on roof) the car was reseted (clock different time, tune lost station presets, odometer 0miles) - why i never guessed?


Can a 'very dirty' oil filter cause this problem? Could it be the cap of the oil inlet (its a bit torn out)? If electronic fault would removing the battery from the car for a while help (a raw kind of reset)? What could be other problems?

Hi , as they said you can wreck the old filter to get it off - changing oil and Filter is always a good thing..

the sprayer will have removed the battery of the car.. that is why the clock, trip meter , etc are strange

just try and check the connection of the oil pressure switch to make sure there is not a corrosion / poor connect issue:idea:

here's it's location ; Lower Right of pic = Crank Sensor,

( next to the base of the Oil filter)

the 2 x cables / wires are for the Crank sensor ( large plug),
and Oil pressure sender = smaller plug = undo the clip , spray the connection with a WD40 type fluid, and reconnect,

I had a suspicion your oil pump could be failing...,
but if the light goes out on start-up it is working o.k.,

Charlie

 

[Stephen505]

Thanks very much guys! Unf. I have done nothing else driving another 100km with normal fuel consumption (44mpg). I have not experience any significant oil leak (some drops) and gearbox and engine noise normal. I know I might be risking but I really had no time and had some imp. errands. I will tackle the two things mentioned here - oil filter change and oil pressure switch check.

I will keep you informed. I changed the oil so it's a pity I have to change it again (better safe than sorry though).

Thank you very much!

 

[Stephen505]

Just a small update... I've now changed the oil filter and the problem is still there. A rush visit at the mechanic and he cleaned the switch (quite quickly?!). Still same problem, although - maybe a placebo effect! - the flashing is somehow less frequent.

On startup (without ignition) the oil warning is on. Just after ignition, the warning lamp is sometimes ON but often it goes off. During driving, the flashing is a bit random/erratic but often it goes away during pressing the accelerator pedal to drive/speed up and appears during free/no drive. :bang:

 

[jon1612]

Just a small update...

On startup (without ignition) the oil warning is on. Just after ignition, the warning lamp is sometimes ON but often it goes off. During driving, the flashing is a bit random/erratic but often it goes away during pressing the accelerator pedal to drive/speed up and appears during free/no drive. :bang:

Change the oil pressure switch straight away, if that dont cure the light then its low oil pressure and DONT DRIVE will need new oil pump

 

[fingers99]

:yeahthat:

And quickly! If it is low oil pressure -- rather than the switch -- you're wrecking the engine.

 

[jon1612]

:yeahthat:

And quickly! If it is low oil pressure -- rather than the switch -- you're wrecking the engine.

Yes fingers99 is right, change switch before you run it.

 

[Stephen505]

I had a suspicion your oil pump could be failing...,
but if the light goes out on start-up it is working o.k.,

Additionally, the miles per gallon is a normal 44-45mpg so I believe there is no wreckage / load on the engine, otherwise the mpg will go down.

Nevertheless, I have an appointment with mechanic to change the switch, although after cleaning it a little I think it went better and I wish to remove the switch myself and give a better cleaning to see what happens! Is it a difficult task - I have no pit

 

[varesecrazy]

it should only be case of unclipping the wire / lead /cable , then using a spanner to undo the switch..like a bolt..!!

use a RING spanner if possible,
I suspect it's Electrical cleaning ..rather than mechanical thit will give the best results,
make sure the terminals of the switch and cable are A1 on reassembly,

" brake cleaner" aerosols are good,
maybe clean the internals of the switch with it too, JUST make sure that it's all evaporated before refitting..,
Charlie

 

[s and b]

it should only be case of unclipping the wire / lead /cable , then using a spanner to undo the switch..like a bolt..!!

use a RING spanner if possible,
I suspect it's Electrical cleaning ..rather than mechanical thit will give the best results,
make sure the terminals of the switch and cable are A1 on reassembly,

" brake cleaner" aerosols are good,
maybe clean the internals of the switch with it too, JUST make sure that it's all evaporated before refitting..,
Charlie

hi varesecrazy im going to disagree with you here
these switches work on oil pressure and once they go faulty they leak all the oil out as you drive ,thing is you dont know all the oils gone till the light stays on if your lucky then its too late,they have a good quality factory electrical clip on so unless someones broken it then they never fail
to summarise -------this switch needs changing ,the cost should be €10 abouts---------
a long reach socket of about 22mm fits but you have to get it to just touch the hex bit or your ratchet wont fit on if you understand me
you dont need no pit you just need to bend your back

 

[jon1612]

Just CHANGE it, cleaning will do no good, if its blocked it will unblock it
but if its cleaned and still does it then its either faulty or oil pressure is actualy low, like i said back to basics its a pressure switch supposed to activate when pressure reaches a certain level ( by the way it goes open circuit when up to pressure and short circuit when below pressure so electrical cleaning will make no difference at all as a bad electrical connection would stop it comming on at all. once engine is running and switch up to pressure it stops current running through light
see attached picture

 

[jon1612]

Just CHANGE it, cleaning will do no good,

just a quick diagram to explain how oil pressure switch works, when working the pressure forces the pressure plate upwards and opens the contacts the problem comes when pressure plate seals leak and allow pressure past the plate equilising the pressure and so allowing the spring ( not shown ) to push the contact and pressure plate back down
in normal use as soon as the engine is running a small amount of pressure will move the contact plate, when the switch starts to go faulty it will require more pressure to move the plates hence flickering on tickover or goes out when you rev it. the top (electrical chamber is usualy sealed but can be vented so if you have oil seeping out then the seals have definatly gone, they are throw away so just replace.
hope this helps

 

[varesecrazy]

hi varesecrazy im going to disagree with you here
these switches work on oil pressure and once they go faulty they leak all the oil out as you drive ,thing is you dont know all the oils gone till the light stays on if your lucky then its too late,they have a good quality factory electrical clip on so unless someones broken it then they never fail
to summarise -------this switch needs changing ,the cost should be €10 abouts---------
a long reach socket of about 22mm fits but you have to get it to just touch the hex bit or your ratchet wont fit on if you understand me
you dont need no pit you just need to bend your back

my guess was they lived somewhere quite remote,
days from parts, and wanted to "have a go,"

strange how it goes out on cranking..which is minimal REVS, then also goes out at higher revs..,
so maybe a strained wire/ poor connection, engine rolling under accleration,etc

I fully agree all the other bits point to a failing pump/ minimal flow..

BUT this would be too much for the layman to tackle..,

checking wiring thoroughly is always a good + cheap first stage in my book,
Charlie

 

[jon1612]

strange how it goes out on cranking..which is minimal REVS, then also goes out at higher revs..,

classic faulty switch problem, pressure in switch has disapated as soon as turned over pressure causes switch to work properly but as pressure build up seeps past seals in switch
still stand by my diagnosis of faulty switch, especialy if they still driving it about would be more severe problems by now

 

[jon1612]

sorry should have pointed out in last diagram that is older type switch
the more modern compact one are slightly different in that instead of a plunger plate they have a corragated metal diaphram that flexes under the pressure from the oil and the contact plate is rivetted through the centre but works just the same the metal diaphram also acts as a spring returning back to its original formed shape when the pressure is removed.

see pics

 

[Stephen505]

Hi friends...

The picture is getting quite interesting. During the Christmas weak the mechanic was unavailable. I strongly believed that the problem is the switch so I kept driving, noe some 500miles from the warning light. During this time the consumption (mpg) remained normal, oil level constant, engine running smooth, but the frequency or period that the oil pressure warning light was on reduced gradually, and by today it flickers temporarily every now and then (almost seldom!)

I don't know what has happened (miracle!) but maybe the new oil and oil filter had cleaned some blockage in the switch. One thing which accidently might have helped was that I had low water level in the radiator for one trip and so the temperature raised to 75% in the traffic now and then (until radiator fan cooled the engine). So my hypothesis is maybe that the overheated engine made the oil hotter and further helped to remove any dirt in the switch - off course just an assumption....

I just wanted to report what's has happened in the meantime.

Hope it becomes useful.
I keep you updated if anything new happens. Message me if you require further details.

Happy New Year
:worship:

 

[Ziggy122]

Id be worried that the strainer migyt be blocked... yes the new oil may have helped clear it....

But id be getting the oil pressure tested

Irirc puntos it 4bar at 3k or 4k rpm

Ziggy