Technical Low engine oil pressure at low revs when hot

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Technical Low engine oil pressure at low revs when hot

Morty Mort

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Just finished a 6500 km family trip with a fully loaded Stilo and caravan. I admit the facts that the Stilo was overloaded in general before the roofbox came on and added 100 kilos more. Then a caravan of 1150 kg. Engine? 1.6. So the engine has generally been working constantly between 3000 rpm and 5500 rpm with full throttle, coping with hills and curves.

After a petrol fillup at 5000 km I got the message low engine oil pressure, stop engine, do not proceed, return to dealer. That was not an option, being in the middle of nowhere in Sweden. So I put on FiatECUScan but could not find any faults at all. The fault disappeared when revs reached 3000 rpm, and would not appear again until the revs dropped to 2000 rpm. If it dropped more, I had to get it to 3000 rpm again for the message to clear. So I took the chance and drove 500 km in the same hard spirit as the other 5000 km. :D But it was still 1000 km home, and we stopped for the night. When starting up again, the fault did not appear at all, until engine temp reached its normal position - the fault was back again, for 1000 km.

Have I worn out some parts in the engine? If so, I am not surprised - it has got serious beating. But it has been very effecient, and the gearbox and clutch is incredibly strong.

Or can some other faults trigger this kind of fault? I have done nothing with it yet. Perhaps the oil got so hot, that it got too thin? It's 0w40 in it. Oil and OEM filter was changed the day before the trip, and it has used about nothing of it. Engine goes steady at 750 rpm, but I imagine some tiny constant puffs from the exhaust.

I'll start with this, next weekend:
- Battery off and charge for a day.
- Throttle relearn.
- Throttle cleaning.
- Oil pressure switch cleaning (if I can find it).
- New oil filter.

Any other sensors?
Plugs? They have just done 20.000 km.

.MW.
 
You will find the oil pressure sensor bang on where the oil filter screws onto its housing, if it's anything similar to the 1.2.

It could be that the teeth of the oil pump have worn faster than normal due to the fact you've been doing consistantly above 3000rpm lol

You could remove the oil filler cap and rev it to see how much oil, if any, is reaching the top of the engine?
 
Mobil 1 New Life 0w-40. Is grade/wheight the same? Been using this one for 2 years.

hmmm i wouldnt have thought your oil choice would have been a problem then ... maybe if you were using 0w30 or 0w20 but 0w40 would be good... when did you last service her buddy?

(grade and weight i suppose are the same thing i usually use 'Grade' to define its API rating and 'Weight' to define the *w** rating)
 
You will find the oil pressure sensor bang on where the oil filter screws onto its housing, if it's anything similar to the 1.2.

Will have a look this weekend. Just have to drive on them ramps. If I remove the sensor, will oil pour out?

It could be that the teeth of the oil pump have worn faster than normal due to the fact you've been doing consistantly above 3000rpm lol

And this one is attached to the timing belt perhaps? Which was changed 3 months ago when the tensioner started yelling.

You could remove the oil filler cap and rev it to see how much oil, if any, is reaching the top of the engine?

How would I see if oil reach the cams if I open the filler cap and rev it? Will it splash up? If so I could get my wife to rev when I watch it.

I remember on the old Ritmo Abarth (Strada 130TC in the UK) the rocker covers were tightened with round bolts for secure finger grip, to quickly examine the cams. If i open the rocker covers (or is it just one) for inspection should I have a new gasket ready?

Morten.
 
0w40 would be good... when did you last service her buddy?

I have had the car for almost 7 years, and not had it in for service. :D Done everything myself except for cambelt/timingbelt change and exhaust repairs.

It's in great condition - but she works very hard. Gone 110.000 km but well taken care of. I generallt follow the service intervals given from Fiat (have the "checkmark" document). Had a major change of everything a year ago, being coolant, aircon, radiator, plugs, exhaust etc. Cambelt changed 3 months ago by Fiat.

Engine runs smoothly. But I will know more tonight when my wife is home. Perhaps I should have an oilcooler during caravan towing?
 
Will have a look this weekend. Just have to drive on them ramps. If I remove the sensor, will oil pour out?



And this one is attached to the timing belt perhaps? Which was changed 3 months ago when the tensioner started yelling.



How would I see if oil reach the cams if I open the filler cap and rev it? Will it splash up? If so I could get my wife to rev when I watch it.

I remember on the old Ritmo Abarth (Strada 130TC in the UK) the rocker covers were tightened with round bolts for secure finger grip, to quickly examine the cams. If i open the rocker covers (or is it just one) for inspection should I have a new gasket ready?

Morten.

I'm pretty sure oil will pour out when you remove it, it is screwed in next to the filter housing so I presume it sits somewhere inside an oilway.

Not sure how the oil pump works, I'm sure it's an impellar pump but not sure whether it's driven off the crank pulley or what...

Yeh you should be able to see the cams working, though on the 1.6 I'm sure each cam is held in seperate cam covers so I'm not sure what you'll see, take the filler cap off anyway and have a gander :D

Here's a picture of the oil filter/pump, don't know what to make of it, Richy has the 1.6 as well I think, perhaps he will shed light on it :rolleyes:

Stilo 1.6 lube.png
 
Yeh you should be able to see the cams working, though on the 1.6 I'm sure each cam is held in seperate cam covers so I'm not sure what you'll see, take the filler cap off anyway and have a gander :D

As the car is not home at the moment, I have to rely on my memory. And that tells me I will se nothing when I remove the filler cap. It's like a tube going straight down on front of the engine. The breather pipe is directly connected to it... Will let you know.

Thanks.
 
I have had the car for almost 7 years, and not had it in for service. :D Done everything myself except for cambelt/timingbelt change and exhaust repairs.

It's in great condition - but she works very hard. Gone 110.000 km but well taken care of. I generallt follow the service intervals given from Fiat (have the "checkmark" document). Had a major change of everything a year ago, being coolant, aircon, radiator, plugs, exhaust etc. Cambelt changed 3 months ago by Fiat.

Engine runs smoothly. But I will know more tonight when my wife is home. Perhaps I should have an oilcooler during caravan towing?

if you run high mileage bud id be expecting an oil change every 6-8 months rather than 12. Also you will find that under heavy loads due to the extra work the engine is doing the oil degrades faster and thins out so if your doing many journeys working the engine hard up and down your scandinavian hills, you would have to drop oil more regularly than our dutch counterparts.

I do just shy of 15,000 miles a year and i drop my oil every 7-8 thousand miles once in Feb just before my MOT and one just at the end of Aug... my Cinq used to get dropped every 4 thousand miles so every couple of months because it was driven so hard. I've always dropped oil before the manufacturer recommended i dont know why i just do... its not a bad practise to get into but its a damn expensive one ;)
 
You are right, look at the picture I posted, the camshafts are located in seperate cam covers and it doesn't look like the oil filler goes through either of them. I wouldn't bother with it...

Is it possible for the oil pressure sensor to become dirty and give false readings? If so then perhaps the consistantly high revs/ oil pressure has cause some grime in an oil gallery to clog up the sensor?
 
if you run high mileage bud id be expecting an oil change every 6-8 months rather than 12. Also you will find that under heavy loads due to the extra work the engine is doing the oil degrades faster and thins out so if your doing many journeys working the engine hard up and down your scandinavian hills, you would have to drop oil more regularly than our dutch counterparts.

I do just shy of 15,000 miles a year and i drop my oil every 7-8 thousand miles once in Feb just before my MOT and one just at the end of Aug... my Cinq used to get dropped every 4 thousand miles so every couple of months because it was driven so hard. I've always dropped oil before the manufacturer recommended i dont know why i just do... its not a bad practise to get into but its a damn expensive one ;)

The Norwegian service interval is harder than our southern European intervals. Oil is to be changed every 6000 km (3600 miles) , and timing belt every 3rd year etc.

But I didn't know that oil degrades over time due to heavy load. That might be the issue... I'll try to put in some synthetic 5w40 (usually pretty cheap) with a new filter to test it. The Mobil 1 0w40 is rather expensive, but it completely cured the "diesel clatter" (still a 1.6 petrol) when coldstarting in -15°C.

What still is strange is that on long hard journeys the car use zero oil. Like this one at 6500 km - not a drop. After 6000 km with short journeys and city driving constantly start/stop/hot/cold, at least a litre vanish into thin air. It's always been like this.
 
The Norwegian service interval is harder than our southern European intervals. Oil is to be changed every 6000 km (3600 miles) , and timing belt every 3rd year etc.

But I didn't know that oil degrades over time due to heavy load. That might be the issue... I'll try to put in some synthetic 5w40 (usually pretty cheap) with a new filter to test it. The Mobil 1 0w40 is rather expensive, but it completely cured the "diesel clatter" (still a 1.6 petrol) when coldstarting in -15°C.

What still is strange is that on long hard journeys the car use zero oil. Like this one at 6500 km - not a drop. After 6000 km with short journeys and city driving constantly start/stop/hot/cold, at least a litre vanish into thin air. It's always been like this.

try using an oil labelled up for diesel engines... they have more 'detergents' in them and better 'Anti Sheer' properties meaning that the degredation is lessened over any given time period and load usages. basically its like stretching elastic when its new its lovely and springy so the oil particles cling together better in fresh oil... after pulling and squashing it repeatedly in the engine it looses its elasticity you end up with a thinner oil at any given temperature because the 'elastic' is worn out... strange analegy i know but its the best way i can describe it.

dont worry about using diesel engine oil in a petrol car its perfectly safe pretty much the only difference is the 'detergent' content which helps combat the build up of carbon particles inside the engine and it has beter anti sheer properties, so it keeps its elasticity for longer if you will
 
Changed oil to 5w40 and filter (OEM) for a start. It was oil everywhere around the engine and under the car all the way to the gas tank. :eek: Very nasty.

Still on ramps I started the car, and oil started dripping from what I'd think was the pressure sensor - from the electric plug to be correct. I didn't dare touch it, and will be grandma-driving for a week and ordering a new sensor.

Can I buy a sensor that can route an additional analogue signal to a cool little needle on the dash?
 
Changed oil to 5w40 and filter (OEM) for a start. It was oil everywhere around the engine and under the car all the way to the gas tank. :eek: Very nasty.

Still on ramps I started the car, and oil started dripping from what I'd think was the pressure sensor - from the electric plug to be correct. I didn't dare touch it, and will be grandma-driving for a week and ordering a new sensor.

Can I buy a sensor that can route an additional analogue signal to a cool little needle on the dash?
Was a leak causing the low oil pressure warning?
 
Was a leak causing the low oil pressure warning?

Just a follow-up as I completely forgot. Either the leak was causing the low oil pressure warning, or the sensor (mechanical) itself failed due to wear, hence producing its own warning signal.

Anyway, I changed the sensor. I had a hard time removing it as it was deep offset into the top, and in addition very long. After getting struck by both a falling big wrench and a four-battery-size MAG lite straight onto my forehead, I got the bright idea of a ignition plug remover - it fit perfectly. Took 30 seconds to remove, 2 minutes to reinsert due to late night work...
 
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