Oil Pressure Light scare

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Apr 7, 2004
Houston, Texas
First of all just wanted to say what a great site this is
. I've been browsing in here for some time now and its become obvious that I don't know as much as I thought I did when it comes to oil's. With that out of my way here is my problem.

Yesterday while stuck in traffic I caught a blink on the dash out of the corner of my left eye. Didn't know what it was at first since it went right back out. Well I started fooling around and to my horror realized that it was my oil pressure light
. I could only get it to blink on if I turned on the A/C which of course drops the idle rpms just a hair. Even then the light would "stutter" on and off. Any increase in RPM's and it stayed off for good. Scary. I'm about 100 miles into my AutoRX rinse running Penzoil 5W-30W, car wasn't hot, ambient temp was probably around 75 degrees. Generally I run Amsoil 5W30 with an Amsoil filter, but after doing some research here it seems like that is too light and I maybe I should consider running 5W-40. The car is a '96 Impala SS W/LT1 and it has 130K on it. I bought it with about 75K on the clock and now I'm starting to wonder about the previous owners maintenance practices.
My first thought is my main bearings are worn and out of spec. Any suggestions on what oil to run? Keep in mind down here it gets hot, really hot, in the summer and idling in heavy traffic is going to be the norm. Thanks for the help!
That would be where I would start, moving up to a thicker oil. Especially where you live and summers a-coming. The RX may have cleaned out some of the nooks and crannies and the oil is starting to flow around better meaning it will take more oil pressure. You want to increase pressure, move up in viscosity. This may sound stupid, no disrespect, but have you checked your oil lately and see if perhaps your a little low? In my above reference to the RX, maybe some of passages are now cleared and thus requiring more oil. You could have a filter going out and it's starting to show signs of failure. Listen to what other have to say below......
No harm in asking! The oil level is SPOT ON and of course was the first thing I checked. The oil and filter at this point have 100 miles on them. I went with a cheap filter (NOT FRAM) since its only going to be on there for 1000 miles or so before I do another RX cycle.
Wouldn't hurt to get a real oil pressure gauge, but T it in so the light is still functional. Call the dealer and ask what pressure the light comes on at. That will give you an idea of what the pressure is at least at idle.

Where you live, I cannot think of any good reason for a 5wxx oil. You probably can run 15w40 year round down there, but could do 10w40 in the winter for easier starts. Hey, I am using 10w40 in winter here in Detroit where it actually reaches 0F at times.

I was getting 36 psi (16 at idle) with 5w30 and when I went to 10w40 it jumped up to 45 psi (22 at idle).
A couple of thoughts on this. First, although our engines are very different (mine is a 3.0 Toyota V-6), my manual actually states that a flickering O/P light is OK at idle. Personally, I'm not very confident about that, but I've never seen it happen either, so I'm not too worried about it. Toyota obviously knows they are telling customers to use thin oil (5w-30 primary, 10w-30 permitted), so I suppose they are trying to diffuse the panick attacks in advance via the manual. Have you checked your manual to see if it has a similar "disclaimer"? Perhaps the same idea applies in your much larger GM engine.

Second, I'd say go ahead and put a good filter on despite the short interval. We're only talking about roughly $10 max for a premium vs. about half that for a cheapy, and I'd think that now (with an active cleaner on board) more than ever, you'd want the very best filtration. This would be especially true if your car was previously owned by some awful sludgepacker and God only knows what's coming loose as you clean it. I recall reviewing the literature on another cleaning product a few months ago (duh, I can't recall which...) and it specifically recommended not giving in to the temptation to use an inexpensive, low-grade filter.
Edpolk, my theory on the cheap filter was if its going to get full of gunk then a more free flowing filter would be better than a more restrictive one. The idea being the more restrictive would be more prone to getting stopped up. Flawed thinking maybe but at the time it made sense.
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