Oil/Coolant lamp comes on and off - Gauges show normal pressure

[Petesexpy]

So I was dropping my son off at his friend's house when oil/coolant warning light blinked. Then, on my way home, the light came on momentarily after hard breaking for a traffic light, and then went off. The gauges show everything is normal. I checked oil and coolant levels and they were normal. Is that an oil pressure switch? are there two of them (switch for light and sending unit for the gauge)?
It is 2000 expy with 4.6 L engine.

 

[1955moose]

Could be, or maybe a warning you've got coolant mixing in with oil. Pop off radiator bottle cap, run it up to temp, see if your bubbling or smelling any exaust smell. It could just be a weak oil pump starting to clog on screen due to debris from timing chain tensioners. You may want to pull your oil pressure switch and screw in a known good automotive testing gauge, to see pressure. Better to know now if their is any issues.

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[Petesexpy]

Could be, or maybe a warning you've got coolant mixing in with oil. Pop off radiator bottle cap, run it up to temp, see if your bubbling or smelling any exaust smell. It could just be a weak oil pump starting to clog on screen due to debris from timing chain tensioners. You may want to pull your oil pressure switch and screw in a known good automotive testing gauge, to see pressure. Better to know now if their is any issues.

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Well, if it was weak oil pump, I would see low oil pressure on the gauge. As I said, Gauges are normal, both for oil pressure and coolant temperature.

 

[1955moose]

Not always. Sometimes a stock gauge will read fine, but in reality the pressures not there. That's why I suggested using a separate gauge. You may be right, it could be just a failing sending unit, probably is, but I'm overly cautious on things like oil pressure. I hope your issue is easy. Let us know.

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[Trainmaster]

The oil gauge is fake news. It has two positions: Normal pressure and No pressure. It's a glorified idiot light that doesn't show how low or high the pressure really is.

The light comes on when the oil pressure is low or when the car is overheating. You sure it's not running hot?

 

[Petesexpy]

The oil gauge is fake news. It has two positions: Normal pressure and No pressure. It's a glorified idiot light that doesn't show how low or high the pressure really is.

The light comes on when the oil pressure is low or when the car is overheating. You sure it's not running hot?

No, no overheating. Now both the gauge and light come on when stopped in gear. They go off when idling in Park or Neutral. I found same symptoms on line with pressure switch. I found out my switch is also leaking oil indicative it's the switch that's the problem. I replaced it, so we shall see. I'll update tomorrow.

 

[1955moose]

Don't you love it when a plan comes together!

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[Petesexpy]

Yup, it was the switch . No more light. And I learned that the gauge does not show the pressure (it's just an on/off thing which makes sense, since it's just an oil pressure switch rather than a sender).

 

[1955moose]

Good deal. Can't tell you how many people think just because the oil pressure looks normal, they don't need to check level. Had a friend years back that owned a Peterbuilt with a Cummins diesel motor. He had a driver that would do runs here in California. When my friend confronted his driver why the rig was down 3 quarts of oil, his comments were the gauge was fine, I didn't think I needed to check it!

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[Petesexpy]

Good deal. Can't tell you how many people think just because the oil pressure looks normal, they don't need to check level. Had a friend years back that owned a Peterbuilt with a Cummins diesel motor. He had a driver that would do runs here in California. When my friend confronted his driver why the rig was down 3 quarts of oil, his comments were the gauge was fine, I didn't think I needed to check it!

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Yup. And I learned (or my Dad did) that if your oil light goes off (or on) due to low oil level, it's too late. In fact, in the older cars, the oil light would come on just to warn you that you needed a new engine...