Oil Pressure Low. Really low...
05-21-2009, 06:50 PM
#17
I would always go with the Mahle Oil filters directly from Porsche/online source. Oil now that is an entirely different question with no real right answer. That argument has gone on for a verrrrrryyyy long time. I personally always Mobil1 products because it is relatively cheap and typically always available. Like I said I use 15w50 purely because it is a well rounded oil for the Midwest temps, easy crank on the cold mornings and will stand the high summer heats. There may be better oils out there and I am sure that others will chime in as well.
05-21-2009, 07:08 PM
#20
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Okay. I have some VR-1 ready to go at my parts store (I'm at work and I'll pick it up tonight) and a K&N Filter there too. Because of the urgency of the weekend, I had to go with K&N as I couldn't wait for the UPS truck.
I wanted to do the swap first thing in the morning because I wanted to put some miles on the new oil before beating on the car on Sunday.
I wanted to do the swap first thing in the morning because I wanted to put some miles on the new oil before beating on the car on Sunday.
05-21-2009, 07:11 PM
#21
Cool. For one oil change the K&N should do fine. The reason you typically want to use a Porsche filter is (from what i have been told) because it provides a direct flow of oil to the motor which will allow you to start the car cold and just run with out having to wait for warm up (read in the manual). I don't know if the other filters account for this.
05-21-2009, 08:00 PM
#23
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Sweet.
I hope this brings the pressure up a tad so I can have better piece of mind during autocross weekends. I just grabbed the oil (long lunch break) and I have to run to the warehouse tomorrow for the filter. Then I'll throw the car on the rack and drain that Castrol out and drive the car tomorrow and Saturday, hopefully at least 100 miles, before the event on Sunday.
I hope this brings the pressure up a tad so I can have better piece of mind during autocross weekends. I just grabbed the oil (long lunch break) and I have to run to the warehouse tomorrow for the filter. Then I'll throw the car on the rack and drain that Castrol out and drive the car tomorrow and Saturday, hopefully at least 100 miles, before the event on Sunday.
05-21-2009, 08:46 PM
#24
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From Clark's Garage:
The 944's oil pressure should run 4-5 bar at idle when the engine is cold. It will gradually decrease to 2-3 bar at idle as the engine oil warms to normal operating temperature. Once the oil is at normal operating temperature, the oil pressure should indicate around 4 bar at 5,000 rpm. It takes the oil longer to reach its normal operating temperature than the coolant. Therefore, don't be surprised if oil pressure continues to decline after the coolant temperature has stabilized at its normal operating temperature. Occasionally, you may see your oil pressure drop to less than 2 bar. This may happen on very hot days when the car has been driven particularly hard. You should be extremely concerned if the oil pressure dropped to less than 1 bar. This is indicative of an problem with the oil pressure indication or the oiling system itself. Under these circumstances, the car should not be driven until the cause of the low oil pressure indication is determined and corrected.
05-22-2009, 01:31 AM
#25
Drifting
my car idles at 2 bar when hot and goes to like 4.1 bar when reved up past 2300 rpm or so. when cold it idles at 5 bar then gradually drops.
i always have used a 50 weight oil like 5w50 , 15w50 or 20w50.
from what I have heard from everyone you should always use a thicker oil, 5w30 is too thin for a 944. newer cars now are designed to run on thinner oil for better fuel economy / efficiency.
1 bar idle is definately too low. I don't think below 2 bar is normal, unless like stated on that clarks garage article when you've been driving for extended periods of time in really hot weather or high rpms then maybe it might drop below 2 bar but that is not good.
I'd change out your oil first and see what happens.
i always have used a 50 weight oil like 5w50 , 15w50 or 20w50.
from what I have heard from everyone you should always use a thicker oil, 5w30 is too thin for a 944. newer cars now are designed to run on thinner oil for better fuel economy / efficiency.
1 bar idle is definately too low. I don't think below 2 bar is normal, unless like stated on that clarks garage article when you've been driving for extended periods of time in really hot weather or high rpms then maybe it might drop below 2 bar but that is not good.
I'd change out your oil first and see what happens.
05-22-2009, 06:07 AM
#26
Three Wheelin'
30W oils are way too thin for these cars. 5W50 has the same cold start up viscosity as 5W30, so there's not much point in using a 30W oil in my opinion.
I used to use a 10W40, but the oil consumption was terrible - especially on the track. I switched to Mobil_1 5W50 and much reduced consumption on the track. Oil pressure at idle not usually below 2 bar. I am in Brisbane Australia and the weather here is generally pretty hot in summer. I would use Mobil 1 15W50 (original fill in Australia when the car was new), but can't get this anymore. I'm considering using semi-synth 15W50 for the next fill.
I used to use a 10W40, but the oil consumption was terrible - especially on the track. I switched to Mobil_1 5W50 and much reduced consumption on the track. Oil pressure at idle not usually below 2 bar. I am in Brisbane Australia and the weather here is generally pretty hot in summer. I would use Mobil 1 15W50 (original fill in Australia when the car was new), but can't get this anymore. I'm considering using semi-synth 15W50 for the next fill.
05-22-2009, 07:02 AM
#27
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Porsche actually has an approved oils list for these cars, updated from time to time. Mobil 1 5w50 is on the approved (also what I use). Most of the oils on the approved list (most recent one I've seen) are 40 weight synthetics, and no 30 weight oils are on the list at all.
My car has been Mobil 1 since new, currently ~175K kms (~103K miles), it burns < 1 litre between oil changes (10K kms, or ~ 6K miles). In fact, I usually go between oil changes without even needing to top up the engine oil.
My car has been Mobil 1 since new, currently ~175K kms (~103K miles), it burns < 1 litre between oil changes (10K kms, or ~ 6K miles). In fact, I usually go between oil changes without even needing to top up the engine oil.
05-22-2009, 03:15 PM
#28
Racer
From Owners's manual:
"At 5000 rpm with engine at normal operating temperature (approx. 90deg. C or 194 deg. F), the oil pressure should be approx. 4 bar.
At idle speed, with the engine oil hot, the oil pressure can sink to 0.5 bar - this does not indicate any loss of engine performance.
However, if the oil pressure drops suddenly while you are driving, or if the warning light comes on, pull off the road and stop the engine and wait for it to cool down.
An occasional brief flickering of the oil pressure warning light at idle speed and normal operating temperature is no cause for concern if the light goes out upon acceleration."
There has been many discussions about what type and weight of oil to use. There has been significant scientific testing done that indicates that heavier is not always better.
Personally I use 5W40 Castrol syntec synthetic (very high ZDDP numbers). My oil pressure is 4-5 bar while driving and 3-3.5 at idle. It did get as low as 2 bar while idling in line after doing repeated back to back runs at an auto-x earlier this year. Stick with a Mahle or K&N filter. Can't vouch for Mobil 1 filter as I have never seen them for sale up here.
For all Porsche models year 1984 and newer no 50 weight oils are reccomended by Porsche. Porsche reccomends synthetic and most are 0W or 5W40.
Dr. Porsche knows best!
"At 5000 rpm with engine at normal operating temperature (approx. 90deg. C or 194 deg. F), the oil pressure should be approx. 4 bar.
At idle speed, with the engine oil hot, the oil pressure can sink to 0.5 bar - this does not indicate any loss of engine performance.
However, if the oil pressure drops suddenly while you are driving, or if the warning light comes on, pull off the road and stop the engine and wait for it to cool down.
An occasional brief flickering of the oil pressure warning light at idle speed and normal operating temperature is no cause for concern if the light goes out upon acceleration."
There has been many discussions about what type and weight of oil to use. There has been significant scientific testing done that indicates that heavier is not always better.
Personally I use 5W40 Castrol syntec synthetic (very high ZDDP numbers). My oil pressure is 4-5 bar while driving and 3-3.5 at idle. It did get as low as 2 bar while idling in line after doing repeated back to back runs at an auto-x earlier this year. Stick with a Mahle or K&N filter. Can't vouch for Mobil 1 filter as I have never seen them for sale up here.
For all Porsche models year 1984 and newer no 50 weight oils are reccomended by Porsche. Porsche reccomends synthetic and most are 0W or 5W40.
Dr. Porsche knows best!
05-22-2009, 05:29 PM
#30
Three Wheelin'
You're correct it is too low. In my experience the light would come on at about 1 to 1.5 bar. Like I said the Oil weight made all the difference in the world. The other thing it did was lower the opp. temp. of the car. I may be way off on this but basically the lower number on the end of the oil (30) means that as the temperature rises the oil breaks down thus having less viscosity allowing it to flow through places that it normally would not. When the car gets hotter the oil breaks down and is not cooling the motor as much so your temps rise inversely to the the Oil Pressure dropping. When I switched to 15w50 the temps went down quite a bit (still runs a little warm) and the pressure came back up.
Feel free to correct me if I'm wrong though! haha
Feel free to correct me if I'm wrong though! haha
I started a thread on this not too long ago.....oil is always a bad topic as it brings out almost religious-level zealotry in some people....but it seems to me that the consensus (and what I found based on what I had looked for) is that in a properly functioning car, you want the lightest xW number you can get away with (so that you don't wear the motor too much until the engine gets up to temperature) and the highest -x number you can get away with. "Get away with" on the lower of the 2 numbers means proper (2 bar or so) pressure at idle when fully warm (OIL fully warm - which takes a lot longer than when your tem gauge is reading normal), and not pegging out with too much pressure on the higher of the 2 numbers. Too much pressure at high RPMs = OPRV opening = no more additional flow volume. So too much pressure is a cooling and lubrication issue as much as too little pressure.
And I think most of us can agree that there is no "right" oil for every 944, or even every class of 944. It depends a lot on wear, driving habits, and environment. As someone else mentioned, do the rod bearings, and all of a sudden you've changed this equation and probably need different oil (more like what was appropriate when the car was new).
As far as filters, anything you get at a local auto parts store is probably garbage, with a garbage drianback valve that will fail before your oil change interval. K&N is snake oil. Just order the OEM Mahles and be happy. Or change your filter more often (like after 2k miles when you realize that it take 1 or 2 seconds before you have oil pressure after you care sits overnight, which is telling you your drianback valve probably has taken a dump).