New 996 Owner... oil pressure issue

Hello, I am the new owner of a '99 C2 Coupe. Purchased the car from California and brought it over to the east coast. It's a 2/98 build C2 with LSD. I really wanted a cable throttle car with LSD and found this one that fit the bill. I have a fair amount of seat time in various 911s and must say I am smitten with the way this 996 drives. I just clicked over 100k miles, did the whole IMS/RMS/Clutch/2nd gear detent/LSD refresh thing as preventative maintenance/while I'm in there as I am planning to daily drive this car (the IMS/RMS were in perfect shape btw). I also put in an LN engineering low temp t-stat and installed the 997 oil pressure relief valve. Here is my issue... once the car is warmed up the idle oil pressure is about 0.5 bar. When driving at 5k RPM the oil pressure is a smidge under 3 bar. The other day it was about 90F+ ambient temp and in stop n' go traffic the oil light came on. Coolant temp was at the 3/4 mark on the gauge. If I blip the throttle the light goes out and pressure comes up but not where I was told it should be. Per the owners manual it states 5k RPM warm should be 3.5 Bar. Two things I believe are an issue. Cooling (is it supposed to run at 3/4?) and Oil pressure (sub 3 bar @ 5k rpm). The passenger side radiator fan clicks on when the AC is active, the drivers does not appear to. Not sure the parameters for the engine lid fan. I've searched ad nauseum across multiple forums and can't quite find a situation similar to mine. Any suggestions on what could cause the low-ish oil pressure and the cooling issue? Thanks in advance Here's a pic of the car as everyone likes pictures...

3/4 is sort of vague. On a hotter day, getting to the right edge of the "0" in the 180 is not unusual. If your fans aren't working...then you may have a resistor issue. easy to test...google search will explain. What weight of oil are you running? Under 3 bar at 5k rpm is not horrific, but its not great either. If someone put in a thin 5w-30 like Mobil 1, that could easily be your issue. I'd also consider testing the sender.

OP - Nice car! Some questions: What weight oil? What is your static oil level with could engine on flat surface? What does the gauge say for temp, other than 3/4? Needle on the 8 or right of the zero, etc? Do you have a Durametric or other comprehensive scan tool? You can operate fans with a Durametric. Might have a resistor issue on driver side fan. That will cause water temp increase. If the a/c is on, I believe both fans should be running. There are posts from Ahsai and others on how to check the front rad fans. From the service manual for engine fan operation: "Switch-on conditions for engine compartment fan (this fan pulls air into the engine compartment) The engine compartment fan is switched on when the engine compartment temperature is > 176 degrees F or the coolant temperature is > 216 degrees F. After-running of engine compartment fan If the ignition is switched off and the engine compartment temperature is more than 140 degrees F, the DME control module remains in readiness for another 20 minutes. During this time, the engine compartment temperature is retrieved every 10 seconds. If the engine compartment temperature is > 185 degrees F , the engine compartment fan is switched on for 20 seconds. If the engine compartment temperature is still > 185 degrees F after this time, the fan remains on for a further 30 seconds."

I agree with everyone above. First, what weight and type of oil are you running? Second, the oil pressure sender is notorious for inaccurate readings. I would change out the oil/filter and oil pressure sending unit, then see what you have.

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Liquimoly 0w40 well past the "0" right at the next hash mark... see example picture. I will test the fans and check the resistors. Thank you Not my picture. Just used for reference. Thank You! 0w40 and the static oil level on flat ground is one bar above the top indicator on the gauge cluster readout. I will dig in to the HVAC OBC for the engine bay temps. I don't have a diag tool of my own but have a local indy who is very generous. Will test that Liquimoly 0w40. From what I've read if the sender is faulty it will give false readings with the car shutoff. Mine doesn't do that. Coupled with the higher running temps and the oil light which comes on in hot idle situation I would assume the sending unit is operation. But I could be wrong.

For 90+ degree days you should run Liquimoly 5W-40. I think the 0W is causing some of the issues. I run Liquimoly 5W-40 down here in Florida. I know, as the oil heats up the 40W aspects come into play, but your oil pressure is just too low. Might even try an oil change with a 15W-50 and see what happens. At your ambient temperatures, that would be okay.

That water temp seems too hot to me.

I am having the exact same issue with my car. Unfortunately, you will find very little answers on the forums for this. Many people post about the problem, but a precious few (or none) ever post what was done to solve the problem. There may be other nefarious issues at play, but I was using 4w40 and I am now running 5w50 Driven and my oil pressure is back up to 1 bar at idle. However ... I did find some non magnetic flakes in my filter and oil and a little bit of brown plastic from the chain guides or tensioners. May be linked to my problem .. maybe not. I dropped the oil pan and found absolutely nothing, and no clogged uptake. Wanted to check the oil pump, as there have been some that have had the gears for the oil pump get destroyed and affected pressure, but can't get to it without dropping the engine. This is where I am now with my oil pressure

Have you cleaned out your front radiators. They might have debris in there.

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my thoughts exactly. 5w40 and 0w40 are the same on the upper end of the temp/viscosity spectrum. Not sure much benefit to be had from switching. For clarification these ambient temps are not the norm. I'm in NY That is precisely why I started the thread. I've yet to come across any uniform info as to what could be causing this problem. Forgot to mention I put an X51 pan on the car and there was no debris when I pulled the old pan. They're spotless

I made a post a few years ago about this exact issue. My issues were pretty much what you described on the idle side. As Jim stated, threads describe the problem but nobody ever finds a solution. One thing I have noticed is the car is typically a MY99. I cleaned my radiators, changed my coolant, replaced water pump, ensured the high speed fans were working, replaced the oil relief piston and spring to the 997 revision, dropped the sump, checked the swirl pots, and even checked the oil pump gears and housing. Nothing was found to be an issue and the situation is still the same. That was 3 years ago now. I run 5w50 in the summer and 0w40 in the winter. I did the High Speed Fan mod (Adding a switch to the footwell to manually turn the Radiator fans on high, I use it when its hot and I'm stuck in traffic). My oil pressure is about 0.7bar typically in the summer, I have not had the oil pressure light flash since I switched to 5w50, but it is still lower than I'd like. My pressure at higher RPM does match what the manual says, I get over 3.5bar at 5k rpm, usually about 4 bar or so. I've put at least 15,000km as my daily driver since that first summer where I noticed the issue and it has not gotten better or worse.

Sam-son, on the picture you posted, the water temp should never go below the "80c" mark and neither above the next index mark. The next index mark is tested to be around 110c. I've driven my car hard in 34c(93f) ambient heat and it tops out at 108c. Be careful with the low temp thermostat, in my car it caused moisture to build up inside the engine during the cold part of the year(temps around +5-10c) so I went back to the original. The engine also runs 10c cooler that time of year and I don't think that is especially good for wear of the internals. The last years I've tested several different oils, my pressure is too high, trying to get it down. I'm running a thick 0w30 weight oil now and it idles around 1bar when oil is at normal temp and around 0.3 when pushed hard. Don't be worried about the idle oil pressure too much, as long as the oil pressure warning light is off it's OK, the enigne doesn't need much pressure/flow just to idle. Keep the A/C on if your driving in city traffic, it kicks in the cooling fans and also raise the idle. As mentioned above, check the half-speed resistors for the fans, they fail frequently. One thing I did which really gave the pressure a boost was changing the chain tensioners. I believe when they wear they start leaking oil(=reduces pressure).

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Are all the people who've found this mythical solution off in some fantasy land enjoying their cars and too busy to let the rest of us in on the secret? The part that really concerns me is that the 5k rpm pressure isn't at the 3.5bar mark. I don't want to inflict horrible amounts of damage to my engine. Interesting... first anyone has ever mentioned this. Can anyone corroborate?? ..noted on the other items. I will just have to drive the car extra hard in colder temps. I think I can sort the temp issue as I have a sneaking suspicion my fans aren't functioning based on what you guys are telling me. Will test and report back. The oil pressure issue is preventing me from driving the car.

Well if the driver's side fan does not turn on, then yes, that would affect cooling. The resistor for this is in the wheel well. It apparently is an easy fix. This alone should help with oil pressure with the engine running cooler. I believe you are right. They are both 40 weight when hot. I did this as well. I made a switch to turn on high or low fans along with the engine fan using the european headligh level switch: https://rennlist.com/forums/996-foru...ling-fans.html I have not heard this. I have heard that : worst case scenario, the bearings are worn causing pressure loss and that is apparently an engine rebuild. or could be the oil pump gears are worn and toast. I've seen posts on this in the 986 section or an internal seal somewhere is leaking - engine teardown or bad sender - but this would show erratic behavior, not low oil pressure ​​​​​​​This is all I have found

High water temp could be the radiators are clogged with dirt between the fins, reducing airflow.

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Welcome first and foremost. As an owner of a 4/98 with LSD and all that jazz, I had the same issue - although not as dire as you have it - creep up last year. The years before were pressure issue free. Especially concerned I was about the oil pressure drops around longer corners (uphill right-handers were the worst), a well known problem for those that race this engine, but since I'm not a racer and my cornering speed were nowhere near critical, it was concerning. I was then running 5W50 Liqui Moly - and always 0W40 Mobil1 before the issue crept up. My car ran equally hot here in Southern California, especially on those hot summer days, and especially in city traffic. I just two weeks ago had my shop install the 3rd radiator kit for extra cooling. My oil pressure went up by a good half bar to full bar under normal driving, and my idle oil pressure is maybe a quarter higher, despite the thinner oil. So, cooling certainly helped. I think my old radiators, despite me cleaning them out regularly, were just not very efficient anymore, and with the 3rd one installed, plus two new side ones, the cooling is much improved, even in stop and go traffic. My oil pressure is not yet exactly where I want it to be, but it's much closer to comfortable (aside from long corners at speed and the resulting drops, even though they're much less severe than before). I'd advise to get the cooling handled. This will improve your issues. And then maybe if necessary going for a baffle/deep sump system. I hope that helps. And yes, I've been reading the forums trying to find a solution myself (the oil pressure thread on here by the folks doing all the testing has some good info, but no solution yet). So I took the plunge and threw money at the problem, with quite a bit of improvement over the issue. I hope that helps.

Ok, let's figure out what it can be. 1. To check if your cooling system is doing it's job, go on the highway(flat terrain) and get a steady speed of around 50-60mph. Keep it like that for 20min(or until the temperature have stabilised) and then check your coolant temp via the A/C unit like this (menu 6c): Unless it's sub zero outside you should see a temperature between thermostat opening temp(83c) and around 90-91c, not much more or less. If it's more the cooling system(radiators/coolant/waterpump) needs a closer look. Don't forget to pressure check the system. 2.When the car is cold and started in the morning, turn on the A/C compressor. Get out and make sure the radiator fans are running on both side in low speed. If this is not working it is possibly the resistors or maybe the relays. 3.While doing check #1, press the clutch and idle the engine until the pressure gauge settles at a steady pressure. How much is it? If the coolant temp is ok but the pressure is still super low, we move on to the oiling system. 4. From #3 we know that the low pressure is not from hot oil but from something mechanical. I've so far not read anyone concluding low oil pressure to be from worn bearings, so let's exclude that. We are then left with bad oil pump or an internal leak. I know that the chain tensioners can leak and also the oil pump can wear out. Replace those two first, chain tensioners are easy so I would start with that. The internal seal mention in another post here I'm not sure where/what that is. It's fully possible that you have a mix of everything.

My 99 c2 runs temp all the way to the final white line, and it�s no problem! Why? Because that line on my car is stage 1 low speed fans, not even 100C, as verified by both Durametric and a cheap ODBII Bluetooth tool. Trust me, dozens of 996 owners think they have cooling issues, but low speed cooling (when the engine is producing 10HP or less) is NOT a problem if the fans are working and the cooling system is working properly. Don�t confuse the dash gauge and Audi AC hack numbers (that might show 116C) for ECU numbers. ECU is king and controls the fans and everything else. I would verify with a tool if your car is the same as mine. After 99, Porsche may have changed the programming to keep owners from freaking out. As for oil pressure, replace the bypass spring piston/assembly in both the oil pump and oil filter, and switch to 50w oil. And/or, get a different oil pressure sender. Otherwise, nothing else you can do without opening it up. Nick is right about the leaky tensioners, those might be leaking and draining off oil pressure, but at $1300 each bank (for a 99), and 7-12 hours of labor, I would make darn sure that�s it, because there are 50 other ways oil pressure can be lost on this engine due to wear. If you do go in and have the tensioners replaced, do too and bottom tensioner pads 4 total.

Good input from Mike, sensors and indicators vary from car to car. $1300 per bank!? I bought all three for around €330(390 usd). Mines a 2000 but I think it's the same tensioners?. Two are very easy to replace and the third(which you do from the engine bay) needs the A/C compressor unbolted. This is easy DIY on the 3.4 (5 chain) engine, just lock the crank and get going, plenty of guides here on the forum....I did it in a short afternoon (3-4h). Just for ref, my car just passed 111k miles (182000km).

Hmm� Well there is this part: https://www.pelicanparts.com/More_In...0896&DID=12035 And there is this part: https://www.pelicanparts.com/More_In...=0896&DID=3026 So I�m confused, other than the fact that one part comes with the solenoid ($500 by itself) and the other is just the tensioner. Edit: maybe the $1300 part includes the actuator as well as the solenoid and tensioner?

Seems you guys are talking about different things. External chain tensioners (Nick_L) vs variocam solenoids/tensioners (Mike).

Good Grief!! How many tensioners does this engine have, lol.

Let's not let this thread get buried! This thread had some interesting info in it: https://rennlist.com/forums/997-foru...ressure-2.html

Some updates.... Was able to spend some time with the car this weekend. Low speed setting on the fans do not seem to kick on. Only the passenger side high speed in conjunction with AC. Ambient temps were lower at night and took the car out for a good romp. The temps stayed between the '8' and the '0' and the oil pressure was exactly as it should be. 3.5+ bar over 3500 rpm. At idle it was still .7 bar but no oil light. Pretty confident this is a cooling issue at this point and nothing related to the oiling system. Taking the car to the indy tomorrow to test with durametric. Will update with more info as I have it. The more time I spend behind the wheel of this thing the less I understand the hate.... all this because the headlights are a bit funky? Way more fun at street speeds than 997s IMO. anyone remember when 964s were the redheaded step-children because of headgaskets? Or G50 cars because of chain tensioners?

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lets hope not... Oil pressure relief valve was replaced. Long term I think I will move to a 50 weight oil. No signs of leakage. First thing I did when I received the car was get it up on a rack and look it over. Bone dry underneath.

Yea, you are right, There you go. It�s always both fans on low or both fans on high, never 1 fan by itself. And low almost always comes on before high, even if AC pressures trigger the high speed fans, because even that pressure takes a minute or two to get there. Maybe a bad resistor or bad fan or wiring somewhere. Durametric can trigger high and low fan operation, so you�ll know right away.

Just for posterity... the front cooling fans were not functioning properly. As a result, the oil temp was getting too high and the viscosity dropping causing an oil pressure drop. It's in the 90s today and about 90% humidity. Fans working properly coolant temp right about the '0' on the temp gauge and oil pressure a hair under 1bar. Seems we can put this to rest as a cooling issue not an oiling issue. Now I can go out and enjoy my car... even if I can't enjoy the weather..

Awesome!!

At what point can I pull my hair out? Drove the car for an hour or two. Temps, pressures, all spot on. Fans working perfectly. Then suddenly..... The temp gauge is misleading in this picture. It's actually closer to the midway mark of the '8' and the '0'. Fans all working as they should. Temp right where it should be. Pressure is the only issue. What isn't misleading is the oil pressure reading. And at full tilt it only reads about 2.9 bar.

What type and weight of oil are you running? Change your oil to a 5W-40 or 5W-50. Get a new oil filter canister and replace your old one. The bypass valve may be weak or stuck open.

Agreed. Change to 50 weight. It made a big difference for me.

I disagree on the oil weight change, your engine should have strong pressure with a 40 weight, look for the actual issue instead.

I have the same problem, but on 997. I verified with a mechanical gauge and it confirmed the oil pressures. Maybe the dashboard shows a .1 lower. This is at 110 degrees Celsius OIL TEMP (not water), first I revved it at 3000 rpm, then higher up to 6000. Didn't reach 4, idle is 10 psi. Below is the video. Oil is Mobil 1 0w40, car is an 07 997 with 106.000 km. When I start it, pressure is 5.5 and as soon as it starts warming, even before the oil needle shows anything above 60 degrees, pressure starts to drop bit by bit. I changed the oil filter housing, oil pressure relief spring and piston, different oils (yesterday I changed to Motul XCess 5w40 because forum people said they got half bar plus with it - for me it didn't change anything) I dropped the sump, everything was clean, no debris at all. The suction pipe was clean, but I didn't think to check if it was cracked. Could be temperature related, but I see the same temperatures at others and pressure is 1.5 bar. I would accept even 1 For reference, I measured my 05 325i which now has 200.000+ km. At hot idle it shows 1.5 bar and at 2000 rpm it shows 4.5 bar. THIS is what the 911 should display too. It really bothers and prevents me from enjoying the car. You Tube

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The bold text: NO, the 911 engine is not designed as other cars. It's a high revving NA sports car engine, they are built to run extended time above 3k rpm. The oil pressure sender sits on top of the engine(at the end of the oil gallery) which means that the reading might not be comparable to the BMW also.

So far as the weight of the oil versus the temperature, say for instance using the Motul 5W/40. At engine first start the engine is cold and the oil acts like a 5W oil and you have 5.5 pressure. Then as the oil heats up, it should act like a 40W oil, but your pressure falls to 1.5. I really suggest you move to a 5W-50 oil. The new "classic porsche engine oil" for our cars is 5W-50.

If you want to understand the causes read all of the later reports from me on the other oil pressure problem posts and if you want a solution contact me. Baz

You can also read Zbombs "Oil Pressure Stability" thread. Within this thread, Baz continues to supply tremendous insight on the problem as well as his solutions, including his contact info. In addition, other engine builders and race shops supply their thoughts and solutions. This thread is technically heavy, but one of the best on RL.

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Good to see you've dropped the pan to verify something simple like excess sealant wasn't blocking the oil pickup. Did you have an overheating issue before putting in the low temperature thermostat? Did you do a water pump at the same time? Also, has the oil pressure issue been present since you took ownership? Not knowing how the cooling system was drained or filled at time of installation of the thermostat. I've seen many cases where there is an air pocket in the system and you'll have random increases in coolant temperature as a result. I've also seen this with engines where the water pump is failing (impeller slipping on the shaft just to give an example). As far as oil pressure is concerned, going to a 5w50 (or even a 15w50 in the 5-chain engines where the engine won't see sub-freezing starts) will help with oil pressure significantly. When the engine is cold and car has been sitting a few days is there chain noise/rattle at startup? Do you know if any other work has been done to the car such as the cam covers having been resealed or scavenge pumps recently removed? I've seen shops having installed the scavenge pump backwards on the heads cause low oil pressure issues. That's something easy enough to check. You might also consider doing a used oil analysis test to make sure you don't have some other hidden issue such as work main and/or rod bearings as well. These are relatively easy and inexpensive first steps to take beyond the basics of making sure the fans are working properly, etc., before considering any further more invasive steps.

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The temp was suspiciously high so I put in the LN low temp t-stat as a preventative measure only to find the fans weren't working. Got the fans working and the temp was a steady 190ish (inbetween the '1' and '8' on the temp gauge). No odd noises or rattles. I'm not sure the scavenge pumps have ever been removed. When I had the IMS/RMS done the cam plugs and tensioner gaskets were done at the same time. The work was performed by an extremely reputable Porsche specialist and was given a clean bill of health. If something was out of place they would've noted it. The water pump appears to have been replaced just before my ownership. My fans seem to have packed up again causing this new temp spike and oil pressure drop. Ordered a new fan and resistor, hopefully that will solve that issue. My next move is changing to a 50 weight oil. I appreciate all the insight on this road to 996 enjoyment.