cytopath

The RPM reading when it fluttered was normal for a startup (around 1K). There was no variation in RPM during or after the fluttering sound.

Searching usenet for similar stories using the words "oil light stays on seconds", I saw several references to variability in filters affecting how long it takes for the oil light to go out at startup. Specifically, it seems there's an anti-drainback valve that may not always be effective, mostly in POS filters.

I saw no reference in the manual about an anti-drainback in the oil system itself... does this exist?

Did you put in an oil pressure gauge instead of the switch? Which one? How hard is this and what does it cost? Should I consider buying a cheap testing gauge or bring it in?

Lastly, the manual calls for 36 psi minimum at idle and 85 psi minimum at 3000 rpm. From your seeing 20psi and not being concerned about it, I'm assuming these figures are for cold oil, or not very important.

xviper

Re: the flutter .................... Could this possibly be the secondary air injection pump. After a "hot" start, this may run for 1/2 a minute or so. Maybe next time, try to duplicate this noise with an assistant, but with you listening under the hood to see if you can zero in on this noise.

I have an Autometer oil pressure gauge as part of my gauge mods. I "T'd" it so I also kept the stock sensor. Here is the "How To" on installing one:
https://www.s2ki.com/forums/index.php?showt...l=gauge++sender
Unless you really need to keep track of oil pressure (like having a supercharger), such a gauge may not be of much use for you (at least in the long term). You might be better off to just get the dealer to take the appropriate measurements for you.

Yes, your quotes on the oil pressures are correct, but understand that this is taken once the engine has reached operating temps (2 fan ON cycles). This is a "standardized" test. At this time, the oil has reached a designated temp for doing this test (and is mostly likely not nearly as hot as after you've driven for some time in very hot conditions. The situation you have been talking about involves a period of time when the oil has become much hotter than this and thus, the lower "real world" readings.

cytopath

No, the flutter wasn't the air pump, which sounds like a whirring sound spooling up like a turbine. On my car this seems to turn off and on quite frequently, even after several minutes of driving, but that would be another topic.

I've since started it cold after 15 hours, and I believe I've narrowed it down to the oil system (most likely the filter) letting the oil drain back down into the sump. I'd appreciate it if you could validate my reasoning, based on these facts:

- Oil level measured after sitting 3.5 hours showed exactly FULL. On startup, oil light was on for 1-2 seconds and I heard the worrisome noise.

- Oil level measured after sitting 15 hours this morning was 1 x below FULL. On startup, oil light was on for about 0.5 seconds. No noise was heard, even though I had hood open and was listening for it.

- After this cold start, idled 30 seconds, engine shut off, and oil was 1 x above LOW mark!

- On startup 3-4 minutes later, oil light turned off instantly.

So there are 2 pivotal questions:

1. Is the stated difference between oil levels normal on a car without a "drainback" problem?

2. Is the stated difference in pressurization speed between hot and cold oil, both equally drained back, normal with a normally functioning oil pump?

xviper

1. Yes. After a cold start, idle for any such short length of time whereby the oil never actually warms up, restart, will cause a lot of oil to "hang up". Cold oil will not drain back into the pan efficiently (far from it). That's why you should never take for gospel the oil level after an oil change, start up to fill filter and immediate shutdown.

2. Yes. Cold oil will exert much more pressure throughout the system than HOT oil. This is also why, on a cold morning (cold start), I can get nearly 95 psi for several minutes while on a HOT start, oil pressure is much, much lower.

cytopath

I probably wasn't completely clear on the questions. On both of them I'm wondering whether the *amount* of difference is accounted for with everything in good condition, rather than whether there should be any difference at all.

Maybe we can compare with your car (or anyone else who is up to it): if you allow all the oil to settle (stop 3+ hours hot or overnight cold) then run the engine for 30 sec (short to avoid heat expansion of the oil), how many fewer Xes to you see if you measure the oil within a minute or two?

Remember, an X is counted where the legs cross... they intersect once at the top, once at the bottom, and 4 times in between. The difference between FULL and LOW being 1qt (~1L), it means each intersection is a little less than 200ml.

As I said, I went from one below FULL to one above LOW on a cold start, which is 3 Xes, or 600ml. This difference seems too high, considering my experience when changing oil... If one were to fill to the FULL mark with a difference of 3Xs, this means an overfill of 600ml! I think I've done this in the past and saw an overfill of about one X mark (<200ml).

Is there really 600ml of oil that fails to drop back down into the engine a minute after it's sopped versus a few hours later? If it's only 200ml as I suspect, I have 400ml extra dropping down after 1+ hours, about the contents of an oil filter...

The second question is less easily quantifiable... do you think cold oil helps fill up the filter faster, or does it just bypass the filter more easily if it's too viscous?

jguerdat

Why not just change the filter and see if there's any difference?

cytopath

I'm about to... been waiting for the car to cool down and the filter to drain itself of oil. I was also hoping to get as much info as possible from the group before doing anything rash

RACER

I doubt the filter is clogged at 3,750 miles, but it won't hurt to change it. It may be better to change it while the oil is hot, as long as you can remove the filter without burning yourself.

cytopath

Well, I've changed the filter... too soon to tell if it worked.

The bad news is there was quite a bit of oil in the filter, as it was heavy and oil was falling out as I unscrewed it, even though I raised up the right side of the car rather than the left side. Either the oil draining out of the filter wasn't the problem after all, or it just didn't happen when I needed it to (per Murphy).

Good news is that the oil light took roughly as much time to extinguish as when the problem exhibits itself. If it now had to fill up a new filter in addition to the old problem, it would have taken both times added together....

Also a good sign is that I added 600ml of oil before starting it up with the new filter, and it indicated about the equivalent of 1 X over full before starting the engine, and 2 X down from full right after shutdown. That's ~600ml down including filling up a filter.

I'll see if the problem ever shows up again... cross fingers.

cytopath

I had to take the car out about 50 min after the startup that filled the filter. Before going out, it was up one X from right after running the engine to fill up the filter, indicating 200ml of drainback. The light went out quickly. It also went out quickly after I spent ~45 min at my destination.

I'll have to see how it does during a few starts after 90-180 min of sitting after getting it hot.

Can someone verify the drainback amount should be 200ml rather than 600ml?