New to me 996 C4S - First oil change and immediately low oil pressure warning?

2004 C4S here guys. Just did my first oil change with it myself. My car has the upgraded LN bearing and spin on adapter. I used 8L of Motul 8100 5w40 and a Napa 1042 spin on filter. Immediately upon startup I�m getting a red low oil pressure warning. What the heck could possibly be wrong? It�s the same oil and filter the car came with and the previous owner used for years. How the heck could I have botched this?

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what LN bearing do you have?

Pretty sure it�s just the single row IMS.

Not trying to be a Jackass, but did you put the drain plug back in? Won't be the first time someone overfilled the drain pan under his car.

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im using the wix 51042. Not sure what is the equivalent Napa number. I also fill 8.5 liters, but I doubt if half a liter will trigger the low oil level alert.

One more thing, how long did you let it run, reason for asking is if the filter was installed dry (not prefilled) may take a moment to fill and cancel the warning.

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Been there, done that. Wasn't my 996 though fortunately.

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I did it on a Cadillac I had (30 years ago) Good thing is, you only tend to do that once............

Wix 51042 is the same filter as NAPA 1042. Wix makes them for NAPA

Well. This might have been a false alarm guys. I went in for dinner, came back and and checked the oil again. It was below half so I added another half quart, retightened the filler cap, and everything is fine now. So some combination of all the above seems to have fixed it. Smh.

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Glad that ended well. I learned a lesson the other day, that you're not supposed to check your oil level when it's cold. I started my car and it was making a ticking noise, the one they say precedes or indicates bore scoring. So I shut it off and checked the oil on the dash because it was cold it took about a minute and then it showed as very low so I added a quart of the motul 8100 and figured that was it, all okay. Because when I started it after adding the litre, wallah, no ticking noise. But then I drove it and of course as the oil gets hot it expands and now when the engine is at operating temperature my dash oil gauge shows as one bar over max which is of course the only bar over max it will show, there's no second bar. I checked via dipstick and it seems quite high as well so there you go I might pump some out or I might go ahead and do an oil change. It's early but I really don't want to risk frothing up the oil with the crank if it's that over full. So anyway yeah make sure your car is at operating temperature before checking the oil. I'm such a noob...I've ordered a small electric 12v pump to pull out the excess x-cess😬. .. Last oil change was about 1k miles and 3 months ago. And at that change I included 1 300ml bottle of liquimoly MoS2. I have a 300 ml of ceratec I was saving for the next change. Maybe I'll use it sooner than I thought. And yes, I'm planning on a cylinder resleeve / new engine for my baby sometime in the near future. There's no denying that tick, but I also haven't done the scope yet, so maybe, just maybe, it's all in my head. Definitely the ticking noise was not just a one time thing. It did stop after I added that quart tho. Paranoia will destroy ya...

I have noticed on my 996 that the dipstick reads about 3/4 of the range when the engine is cold and the oil is "full", then the dipstick reads "full" when the engine is hot and the oil is "full". This is due to thermal expansion of the oil. So I never fill the oil above 3/4 of the dipstick cold. Interestingly, again on my car, the electronic dipstick reads 1 step above half when the dipstick is 3/4 cold. So I interpret that as "full". All on my level garage floor. Sort of like calibrating my car and the oil level measuring devices.

You should check the oil level in a 996 engine when it has been sitting on a level surface overnight and the engine is cold. It should be about 1/2 way between low and high marks. It takes a while fore the oil to drain back to the sump. your can do a lot more damage to the engine by overfilling it than you can by running it a little low on oil. After you start the engine the dash gauge should not read the oil level for about an hour, it has a count down timer. On a 996 Turbo engine you check the oil level with the engine warmed up and idling.

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Could the pressure sender be going? I have read its a pretty easy fix if so. When I do my oil, I get the low oil warning light for a tenth of a second as the oil moves to where it should. Long enough to give me a heart attack the first time I saw it though.

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Perhaps? But just odd to me that there was never a problem until I changed the oil.

My 02 C2 did the same thing when did the first oil change. As soon as I started the engine the oil pressure gauge read zero and the warning light came on. Oil was at the proper level. After a panicked post here most said the oil pressure switch probably went bad. Rennlist was right. Changed the oil pressure switch and problem went away (including when my gauge pegged at 5 bar all the time until completely warm). I never pay attention to the electronic oil level. That's what the dipstick is for. Dumbest thing car manufacturers do is eliminate the oil and auto tranny dipsticks. When I was 17 I once started my 77 Camaro on ramps with no oil in it to get it off the ramps to put oil in it. I shut it down immediately and made sure no one was around to see or hear it (wrong on both accounts)!

+100 This is the way all top veteran 996 owners operate. Top engine builders say the same thing. That�s not to say you have to do it this way, as the owners manual and others can successfully check oil levels while hot, but you have to know what you are doing and take into account why readings will change minute by minute. So doing it cold removes some variables, and thus, input error.

Wow an engine on level ground that has had time for all the oil to drain back to the pan only 996 experts understand this one simple trick

The thing is that the manual states to check the oil when hot, after the engine has been shut off for a few minutes. Obviously the level will depend on how long you wait to let the oil drain back into the sump. On the other hand, it gives you a way to check the oil when you're on the move and don't have time to let the engine cool down completely. Hot oil expands, but not all the oil will have drained back, so I guess the level will be more or less comparable to cold oil in the morning with everything drained? More importantly, I found that the level is extremely sensitive to the surface the car is parked on. In front of my house, the parking spots slope a little bit to the side which makes it impossible to check the level in the morning.

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Are you starting the engine and shutting it down 3 times before letting it run?

The problem is probably at the oil filter. Either there�s an issue with the check valve installed incorrectly, or the filter is installed incorrectly, something like that.

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I haven't read the owners manual since 2014 but I think it also says: "change the oil every 15,000 miles."...That is why I never refer to the owners manual. Worthless as it was mostly written by lawyers and marketing types. IMHO.

Fill the oil filter up with oil before installing it.

Just to touch on a few points mentioned, I did not cycle ignition three times. Wasn�t aware I needed to. As another person stated, I did fill the filter with oil before installing, and lastly, I don�t believe there is a check valve on my car as it has the spin on LN adapter.

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He's talking about the oil filter itself.

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You shouldn�t pre-fill the filter with oil. It actually is more difficult for fresh oil to reach critical areas than if it was empty.

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The fact that one thing is incorrect doesn't mean that everything in the manual is nonsense. Yes, probably the marketing people wanted a (too) long oil change interval, but I don't believe they had anything to do with the way you check the oil. Porsche probably had a reason for that and I think it is because a way to check the oil hot allows you to check it during a track day or long road trip, as opposed to only in the morning.

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I�m not saying you�re wrong, as I too have heard this many time. I just don�t understand why? Oil from the sump pickup must fill the filter before oil can be pushed to other parts of the engine. Aside from the scavenge pumps at the heads, pushing oil back to the sump, how does the time delay of filling the filter from the pump help to oil remainder of the engine? What am I missing?

The other thing to be aware of with the LN Spin on filter adaptor, and it’s not your issue this time, but I have seen it, is to always make sure the filter o-ring seal comes off with the old filter...two seals = major leakage. Just a PSA.

@JTT Here�s the reason, as I understand it: If you pre-fill oil in the oil filter, there's a lot of air trapped between the pump and the filter. Since oil is heavier than air, think of it as a weight that is supported by a column air. As the oil pump starts pumping, the trapped air will need to be compressed first before the oil in the filter will get pushed up to the main bearings. That takes time. Kinda like getting air trapped in your brake system. If not pre-filled, the oil simply gets pumped solidly from the pump to the filter with no resistance as the air is purged through the filter and the rest of the oil passages. Oil will get to the parts faster.

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Sorry I guess I am the type of person that if you(the owners manual) tell me an untruth I am skeptical of everything else you say.

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Porsche has a different reason for checking the oil than I do. Porsche wants to make sure you have enough oil in the pan to operate the engine safely. Checking that it has enough oil in the pan when it's hot serves this purpose. If there's enough oil in the pan when most of the oil is in the engine, then you're good to go. I check my oil in the morning when its cold because that is the highest level the the oil is going to get. I am monitoring for signs that I am burning oil, which is impossible to do when the oil is hot because you don't know how much oil is in the engine. If I get a different result this morning than yesterday morning, I know the oil is going somewhere, and I might have an issue burning oil (or I need to take longer trips).

Wouldn�t there be a lot less air trapped between the pump and the filter if one were to pre-fill the filter and canister? I agree that the trapped air would need to be compressed before being displaced, but if we pre-fill, wouldn�t compression take a lot less time (less air) and result in faster oil delivery to the engine? The only 3 reasons I�ve ever heard about why not to prefil are: 1.) The filter is not vertical, and therefore, way too messy. 2.) Putting oil into the filter on the inside is technically unfiltered oil, so any debris could get to the engine (unlikely, as we are putting in clean oil). 3.) It doesn�t matter much in the long run (sure, oil pressure can take an extra couple of seconds to be delivered to the engine, but how would anyone ever know what the true impact of this is? In any event, to the OP: the most obvious reason why you don�t have oil pressure surely must have something to do with the oil filter. What else was physically removed and put back on the oil system? Unless your sender failed, but man, that�s tricky. Unless you know for sure the sender failed, we have to trust the gauges unless we know for sure the gauge is wrong.

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All I know is my engine guy who knows a crap ton more about these engines than I do says: do not fill the new oil filter with oil before installing. That's good enough for me.

Here are a couple of posts by a well-known expert on the subject. He was discussing newly built engines, but I don�t know why it would be significantly different.

Yeah, that makes sense, as the pump isn�t primed, and so trying to prime a pump, you want as little as possible back pressure as possible, as fast as possible. On a new engine� So maybe an oil change is similar in that the pump, being raised above the oil level in the engine, and also that the oil has been potentially drained from the pickup, now might have air on the intake side of the pump. So the engine starts, the pump starts sucking air and now has to push air through. Pushing air through to other air should be a lot easier, and it won�t take long for the pump to prime and fill up the oil filter. Whereas having oil in the filter/canister is going to be a lot harder to move. Especially that the oil is thick at relatively low temperature.

Thanks Coopduc, that does make some sense.

Learn something new every day 😁

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Good point, if you want to precisely monitor your oil consumption than checking it in the morning is the way to go.