964 Oil pressure
Discussion
Hi
Wondering if anyone could advise me??
recently bought my first porsche - a 1990 C2 tip (I know, probably not much street cred on here being a tip! But couldn't afford a manual) and having some issues with the oil pressure. The pressure generally varies a lot, depending on oil temperature and rpm. It's usually at 5 when at decent rpm and goes down to (between) 3-4 when slowly pottering around the busy streets of London. I assume this is quite normal?????
However, when the oil temp is between 8-9pm and I come to a stand still (even momentarily at traffic), the oil pressure goes so low the warning light comes on. It stays on until we get off underway again and the pressure increases with rpm.
Is this normal or is there something that needs attention?
Any help greatly appreciated.
alex
Wondering if anyone could advise me??
recently bought my first porsche - a 1990 C2 tip (I know, probably not much street cred on here being a tip! But couldn't afford a manual) and having some issues with the oil pressure. The pressure generally varies a lot, depending on oil temperature and rpm. It's usually at 5 when at decent rpm and goes down to (between) 3-4 when slowly pottering around the busy streets of London. I assume this is quite normal?????
However, when the oil temp is between 8-9pm and I come to a stand still (even momentarily at traffic), the oil pressure goes so low the warning light comes on. It stays on until we get off underway again and the pressure increases with rpm.
Is this normal or is there something that needs attention?
Any help greatly appreciated.
alex
Welcome to the world of Porsche. No shame in a tiptronic at all
Oil pressure should be about 4 to 5 when on the gas and about 1 or just over at rest when the engine is warm. Not wishing to teach you to suck eggs, but I guess you know to check the oil level with a hot engine and whilst the engine is running? I mention this because low oil could be the route of your issue. Do not assume the oil fill gague is correct since I have had two play up - typically reading zero when broken.
If the oil level is ok then beyond checking the oil fill cap is on and there are no obvious loose hoses then you've reached the limit of my help I'm afraid. Best of luck.
Oil pressure should be about 4 to 5 when on the gas and about 1 or just over at rest when the engine is warm. Not wishing to teach you to suck eggs, but I guess you know to check the oil level with a hot engine and whilst the engine is running? I mention this because low oil could be the route of your issue. Do not assume the oil fill gague is correct since I have had two play up - typically reading zero when broken.
If the oil level is ok then beyond checking the oil fill cap is on and there are no obvious loose hoses then you've reached the limit of my help I'm afraid. Best of luck.
Hi Masher
Yeah the oil gauge seems to work fine. When I'm at a stand still and the oil temp is between 8-9pm, the oil gauge shoots up to the top (full). When I go up through the revs it then tends to go right down and can be all over the place depending on revs. I assume this is normal.
However, you make a good point. Perhaps the oil gauge isn't accurate and its not got enough oil in the system?
I know how to check the oil as per your advice, but find the tip stick particularly hard to read as only one side seems to be covered.
Yeah the oil gauge seems to work fine. When I'm at a stand still and the oil temp is between 8-9pm, the oil gauge shoots up to the top (full). When I go up through the revs it then tends to go right down and can be all over the place depending on revs. I assume this is normal.
However, you make a good point. Perhaps the oil gauge isn't accurate and its not got enough oil in the system?
I know how to check the oil as per your advice, but find the tip stick particularly hard to read as only one side seems to be covered.
Alexthorpe said:
Hi Masher
Yeah the oil gauge seems to work fine. When I'm at a stand still and the oil temp is between 8-9pm, the oil gauge shoots up to the top (full). When I go up through the revs it then tends to go right down and can be all over the place depending on revs. I assume this is normal.
However, you make a good point. Perhaps the oil gauge isn't accurate and its not got enough oil in the system?
I know how to check the oil as per your advice, but find the tip stick particularly hard to read as only one side seems to be covered.
Worth a check but please do not over-fill. Maybe if you can take a photo of the warning light and gauges someone on here might see the issue?Yeah the oil gauge seems to work fine. When I'm at a stand still and the oil temp is between 8-9pm, the oil gauge shoots up to the top (full). When I go up through the revs it then tends to go right down and can be all over the place depending on revs. I assume this is normal.
However, you make a good point. Perhaps the oil gauge isn't accurate and its not got enough oil in the system?
I know how to check the oil as per your advice, but find the tip stick particularly hard to read as only one side seems to be covered.
Alexthorpe said:
Hi
However, when the oil temp is between 8-9pm and I come to a stand still (even momentarily at traffic), the oil pressure goes so low the warning light comes on. It stays on until we get off underway again and the pressure increases with rpm.
Is this normal or is there something that needs attention?
Any help greatly appreciated.
alex
This should not happen if theres the correct amount of oil in the engine....... unless the engine oil is very very hot (ie hot summer day, standing traffic etc and the oil temp is heading for the red zone). . Needs checking out otherwise.. However, when the oil temp is between 8-9pm and I come to a stand still (even momentarily at traffic), the oil pressure goes so low the warning light comes on. It stays on until we get off underway again and the pressure increases with rpm.
Is this normal or is there something that needs attention?
Any help greatly appreciated.
alex
I've never had the oil light come on, though I'm sure I have read in the owners manual somewhere that the oil light might well flicker if the cars ticking over and gets hot in traffic. If thats the case you should raise the spoiler.
From your replies it sounds like you have a decent oil level. The oil light coming on at idle is fairly common and there is no definitive answer for it. Even your owners manual mentions it:
"The oil pressure should be at least 3.5 bar at
an engine speed of 5,000 rpm. When the oil
is hot, the red oil pressure warning light may
light briefly at idle without endangering the
engine.
However, if the oil pressure drops suddenly
while driving or if the red warning light comes
on, the engine must be turned off immediately.
If there is enough oil in the engine oil
tank, have the malfunction corrected at the
nearest authorized Porsche dealer."
It might still be worth getting a Porsche specialist to look it over. If there's nothing obvious (low oil, a vacuum leak, faulty sender, oil being too thin, dipstick or cap not sealing) they'll probably put it down to a worn engine that could do with a rebuild).
"The oil pressure should be at least 3.5 bar at
an engine speed of 5,000 rpm. When the oil
is hot, the red oil pressure warning light may
light briefly at idle without endangering the
engine.
However, if the oil pressure drops suddenly
while driving or if the red warning light comes
on, the engine must be turned off immediately.
If there is enough oil in the engine oil
tank, have the malfunction corrected at the
nearest authorized Porsche dealer."
It might still be worth getting a Porsche specialist to look it over. If there's nothing obvious (low oil, a vacuum leak, faulty sender, oil being too thin, dipstick or cap not sealing) they'll probably put it down to a worn engine that could do with a rebuild).
Obviously double check you have the correct amount of oil in it but I don't think that this is your problem. Change the oil pressure sender unit it sounds like it could be faulty. Had this issue on my old 3.2 just after it had an engine rebuild. Scared the life out of me but it was just a faulty sender unit. Nothing wrong with a tip by the way. Great cars
graemel said:
Obviously double check you have the correct amount of oil in it but I don't think that this is your problem. Change the oil pressure sender unit it sounds like it could be faulty. Had this issue on my old 3.2 just after it had an engine rebuild. Scared the life out of me but it was just a faulty sender unit. Nothing wrong with a tip by the way. Great cars
+1 for the sender unit or the wiring for it. If you bought the car privately then take it to an indy to get it checked out. If it was from a dealer then take it back - you mentioned you bought it recently?
Whilst all the comments regarding oil level are quite relevant to the well being of the car, it has very little to do with oil pressure. Because the engine has a dry sump system the oil pressure relies ONLY on the fact that the oil pump has sufficient supply. Something around 6 litres, i.e. HALF the full amount, is sufficient for the engine to work well. The additional quantity is there to provide cooling for the engine and to fill out the very capacious oil cooler and pipework. Overfill is MUCH worse that underfill.
As Boxsey has said, the handbook says that the occasional oil light is OK on idle although, in my experience, it's a rarity for the oil temperature to get as high as 9 o'clock and it might be worth exploring why. Problems with the oil thermostat will cause an elevated oil temp quite quickly. Make sure the right front wing can be felt warm when the temp is showing that high. No flow to the cooler will result in a cold wing and suggest a faulty thermostat.
A faulty pressure sender is also worth checking. I recall Boxsey having this exact problem, along with the common oil leak around the seal.
Another issue is the viscosity of the oil. The 964 engine works best with a 10W/40 oil. Running a 5W/30 (like Mobil 1) will likely make the low pressure problem worse.
Dave
As Boxsey has said, the handbook says that the occasional oil light is OK on idle although, in my experience, it's a rarity for the oil temperature to get as high as 9 o'clock and it might be worth exploring why. Problems with the oil thermostat will cause an elevated oil temp quite quickly. Make sure the right front wing can be felt warm when the temp is showing that high. No flow to the cooler will result in a cold wing and suggest a faulty thermostat.
A faulty pressure sender is also worth checking. I recall Boxsey having this exact problem, along with the common oil leak around the seal.
Another issue is the viscosity of the oil. The 964 engine works best with a 10W/40 oil. Running a 5W/30 (like Mobil 1) will likely make the low pressure problem worse.
Dave
computamedic said:
Whilst all the comments regarding oil level are quite relevant to the well being of the car, it has very little to do with oil pressure. Because the engine has a dry sump system the oil pressure relies ONLY on the fact that the oil pump has sufficient supply. Something around 6 litres, i.e. HALF the full amount, is sufficient for the engine to work well. The additional quantity is there to provide cooling for the engine and to fill out the very capacious oil cooler and pipework. Overfill is MUCH worse that underfill.
As Boxsey has said, the handbook says that the occasional oil light is OK on idle although, in my experience, it's a rarity for the oil temperature to get as high as 9 o'clock and it might be worth exploring why. Problems with the oil thermostat will cause an elevated oil temp quite quickly. Make sure the right front wing can be felt warm when the temp is showing that high. No flow to the cooler will result in a cold wing and suggest a faulty thermostat.
A faulty pressure sender is also worth checking. I recall Boxsey having this exact problem, along with the common oil leak around the seal.
Another issue is the viscosity of the oil. The 964 engine works best with a 10W/40 oil. Running a 5W/30 (like Mobil 1) will likely make the low pressure problem worse.
Dave
Thanks for all your feedback. Very helpful, especially knowing how the pressure is affected.As Boxsey has said, the handbook says that the occasional oil light is OK on idle although, in my experience, it's a rarity for the oil temperature to get as high as 9 o'clock and it might be worth exploring why. Problems with the oil thermostat will cause an elevated oil temp quite quickly. Make sure the right front wing can be felt warm when the temp is showing that high. No flow to the cooler will result in a cold wing and suggest a faulty thermostat.
A faulty pressure sender is also worth checking. I recall Boxsey having this exact problem, along with the common oil leak around the seal.
Another issue is the viscosity of the oil. The 964 engine works best with a 10W/40 oil. Running a 5W/30 (like Mobil 1) will likely make the low pressure problem worse.
Dave
Both the pressure sender, thermostat and (very recently) pipes connecting it to the oil cooler are new. When the thermostat was replaced Jaz also checked the cooler unit was working well, which it was.
I took it out last night and it was all very odd. The temp was running higher than normal between 8.30-9pm, the oil gauage was as high as it could be and the pressure below 1 at standstill, with the red light coming on at evey stop.
I will double check the front wing is warm when up to temperature to make sure there's no a problem with the oil cooling. It does sound as though I need to work out why the oil temp is higher than it should be.
It does sound like your temp gets unusually high. In 10 years of ownership, I could probably count on the fingers of one hand how often my oil temp reached 9 o'clock - even if I was missing a couple of fingers. It would mean getting stuck in traffic for some time on a hot mid summers day.
My oil light used to flicker on occasionally if the car got hot. If the temp was at 9pm, it probably would have come on most times.
It sounds a bit odd that all that pressure / temp related stuff has been replaced recently. It makes it sound like they've tried to solve the problem, but failed.
My oil light used to flicker on occasionally if the car got hot. If the temp was at 9pm, it probably would have come on most times.
It sounds a bit odd that all that pressure / temp related stuff has been replaced recently. It makes it sound like they've tried to solve the problem, but failed.
Alexthorpe said:
Thanks for all your feedback. Very helpful, especially knowing how the pressure is affected.
Both the pressure sender, thermostat and (very recently) pipes connecting it to the oil cooler are new. When the thermostat was replaced Jaz also checked the cooler unit was working well, which it was.
I took it out last night and it was all very odd. The temp was running higher than normal between 8.30-9pm, the oil gauage was as high as it could be and the pressure below 1 at standstill, with the red light coming on at evey stop.
I will double check the front wing is warm when up to temperature to make sure there's no a problem with the oil cooling. It does sound as though I need to work out why the oil temp is higher than it should be.
I'm not sure if Jaz changed the oil pressure sender for you or if it was done before you got the car. If the latter, it might be worth checking if an after market one was fitted. I tried two after market ones and they were useless. One had the pressure pegged to the top all the time while the other flicked between 0 and 2 on idle and the occasional red light. The problems with pressure monitoring were resolved by fitting a Porsche original sender.Both the pressure sender, thermostat and (very recently) pipes connecting it to the oil cooler are new. When the thermostat was replaced Jaz also checked the cooler unit was working well, which it was.
I took it out last night and it was all very odd. The temp was running higher than normal between 8.30-9pm, the oil gauage was as high as it could be and the pressure below 1 at standstill, with the red light coming on at evey stop.
I will double check the front wing is warm when up to temperature to make sure there's no a problem with the oil cooling. It does sound as though I need to work out why the oil temp is higher than it should be.
davek_964 said:
It does sound like your temp gets unusually high. In 10 years of ownership, I could probably count on the fingers of one hand how often my oil temp reached 9 o'clock - even if I was missing a couple of fingers. It would mean getting stuck in traffic for some time on a hot mid summers day.
My oil light used to flicker on occasionally if the car got hot. If the temp was at 9pm, it probably would have come on most times.
It sounds a bit odd that all that pressure / temp related stuff has been replaced recently. It makes it sound like they've tried to solve the problem, but failed.
So the first week of ownership the pressure dropped from 5 to 1 whilst on the motorway travelling at 85mph. Scared me to death! Luckily it was only the pressure sender that had gone. So I replaced it.My oil light used to flicker on occasionally if the car got hot. If the temp was at 9pm, it probably would have come on most times.
It sounds a bit odd that all that pressure / temp related stuff has been replaced recently. It makes it sound like they've tried to solve the problem, but failed.
Then I had Jaz look at the oil cooler and thermostat as it was getting too hot especially in traffic. Everything seemed to be working as it should but they replaced the thermostat anyway. It's not made any difference.
Then I had a major leak from the oil pipes. So they were replaced a few weeks ago. I've only given the car a couple of good runs since and all was normal, apart from last night where it was all different.
It should only ever read 9 when in standing traffic for some time. On the move normal temp is just below the 8 mark. The difference in pressure between those two temp points is considerable even at tickover, 0.5 Bar or a little more. If you are seeing 9 while moving then the thermostat is not working correctly.
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