Engine oil pressure light stays on for a few seconds after enginestarts

Hi, I've searched around on this newsgroup about this problem and haven't seen anything like this yet:
I have a 97 SC1 and now have 108000 miles on it. I just moved back to Canada (from the U.S.) and had to take the car to Canadian Tire (~equal to pep boys in the U.S.) to replace the alternater (another story, but I'm not bitter about it). I also had them change the oil because I was there and it was due (this was a week ago). In the past I've changed the oil myself and have never had a problem.

When I was in the U.S. I had a 40-minute commute (each way) at high speeds, now I have a 20 minute commute at low speeds (in the city, lots of starting/stopping). Over this past weekend we had relatives over and whenever we drove somewhere I put the A/C on (by myself I don't normally use it), and at the end of the weekend this oil light problem started.

After I started the car (A/C on) the oil light stayed on. I wondered if it was a "glitch" and just for fun I quickly shut off the A/C. The oil light immediately when off and stayed off. The engine behaved as if nothing was wrong and I never had a problem with it the whole way home.

The next morning, before I started the car, I popped the hood and checked the oil thinking it may be low. To my surprise it was at the full mark. I closed the hood and started the engine (A/C was off). Again the oil light stayed on, but wouldn't shut off this time. I rolled down the window and listened to the engine, but it sounded normal. I put it in gear and the light went off! I drove to work watching and listening carefully but the nothing out of the ordinary happened and the light didn't come back on.

After work I started the engine, and of course the light stayed on again. I popped the hood, checked the oil, even checked for leaks under the car. There was no indication other than that light that there may be a problem. I put it in gear and slowly drove through the parking lot, and this time the light stayed on for an additional 5-10 seconds. I kept the window down and carefully drove back home, but again nothing out of the ordinary and the light never came back on.

If the wrong kind of oil was put in (say a thinner type) would this trigger the low pressure light? I just find it very coincidental these facts:
- I've had no oil problems in the past, when I took care of the oil changes
- Canadian Tire replaces the alternator and changes the oil
- One week later I have this stange problem
- My American plates are still on the car, and I never gave an indication that I'm not "just visiting" Canada.

So that last one is a hint of paranoia. Should I be paranoid? What could cause the light to behave this way?

Thanks in advance,
Tyler

 

It's possible that they used a lighter weight of oil than you were running
before (what was that?), or maybe they used a crap oil filter, perhaps with
a defective anti-drainback valve - I'm pretty sure the Canadian Tire oil
filters are made by Fram, who rather suck, IMHO. I don't think the light
should have stayed on if the oil filter were the problem though.

It's also entirely possible that the oil pressure switch is acting flaky,
it's far from unheard of..

Canada (from the U.S.) and had to take the car to Canadian Tire (~equal to
pep boys in the U.S.) to replace the alternater (another story, but I'm not
bitter about it). I also had them change the oil because I was there and it
was due (this was a week ago). In the past I've changed the oil myself and
have never had a problem.

speeds, now I have a 20 minute commute at low speeds (in the city, lots of
starting/stopping). Over this past weekend we had relatives over and
whenever we drove somewhere I put the A/C on (by myself I don't normally use
it), and at the end of the weekend this oil light problem started.

was a "glitch" and just for fun I quickly shut off the A/C. The oil light
immediately when off and stayed off. The engine behaved as if nothing was
wrong and I never had a problem with it the whole way home.

the oil thinking it may be low. To my surprise it was at the full mark. I
closed the hood and started the engine (A/C was off). Again the oil light
stayed on, but wouldn't shut off this time. I rolled down the window and
listened to the engine, but it sounded normal. I put it in gear and the
light went off! I drove to work watching and listening carefully but the
nothing out of the ordinary happened and the light didn't come back on.

I popped the hood, checked the oil, even checked for leaks under the car.
There was no indication other than that light that there may be a problem. I
put it in gear and slowly drove through the parking lot, and this time the
light stayed on for an additional 5-10 seconds. I kept the window down and
carefully drove back home, but again nothing out of the ordinary and the
light never came back on.

trigger the low pressure light? I just find it very coincidental these
facts:

that I'm not "just visiting" Canada.

cause the light to behave this way?

 

In this order I would try the following:

Check/clean the connector to the oil sender (may have been disrupted during
recent service)
Change the oil filter (strongly suggest using something other than a Fram -
I like Purolator)
Change the oil sender unit (dealer parts counter item)
Change the oil (use what you have used in the past, 10W-30 weight
appropriate for summer)

If you still have the light on, then I would get it in for service ASAP.
Based on your description of the problem and the fact that the engine is
running well, I would bet on either a bad filter or connection at the
sender.

Bob