1981 Chevrolet El Camino, oil pressure problem

Question

1981 Chevrolet El Camino - 305 with around 190,000 miles.

It’s making some noises, so on the most recent oil change last week, I put in 20w-50. I usually use 10w30.

Now today, My oil light came on the dash. Gauge is reading 25-50 which is good.

Would changing the type of oil cause the light to come on you think?

Answer 1

It's possible that the oil pressure switch is bad, that's not uncommon.

Going to a higher viscosity would usually not trigger the oil pressure light. Thicker oil creates higher pressure, not lower.

To know what's going on for sure, you need to remove the oil pressure switch and put in a gauge. You can probably rent one at an AutoZone or Advanced Auto type place. That way you will have a verifiable independent reading, not from your light or your dash gauge.

Comments

Ok, Thanks. I had a feeling changing the oil wouldn't cause the light to come on. That's the only variable that changed, so thought maybe.

I'll check the pressure at the switch.

Answer 2

What kind of noises was it making? Top end or low end? If it's just the lifters rattling you'll likely be okay with heavier oil. If it's a bearing or a rod you're in for a much bigger headache very soon.

Comments

It’s the lifters for sure. It’s really not that bad, but audible.

I’ve read that there’s 2 oil pressure switches on some of these 305s. 1 for the light and 1 for the gauge. I’ve only found one- left of the distributor. Is there any other one?

Thanks!

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I can't remember if it's the 305 or 350 but one of them has an oil pressure sensor on the backside of the engine block on the driver's side. Kind of a pain to get to but if you reach across the top of the engine and feel to the driver's side on the rear of the block there may be a sensor back there.