Does not happen with me.

In summer temps a light (10w30) oil will have lower pressure than a heavy (20w50) oil, which could trigger the light. Since you are running the heavy oil, I would guess your pressure sensor is fatigued...just a guess.
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67 Caribe 1600
76 Ceylon 2002

Be sure your grounds are clean. Run a temporary ground with alligator clips from the general area to the engine block to see if there is any difference. Less than $5.00 to make one from auto store parts. Comes in handy for other things later, other electrical testing, punk rock jewelry, emergency zipper repair and barbequeing of crayfish.
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Ahlem
'76 2002
'90 M3
'90 535i 5 speed
1989 325is

Be sure your grounds are clean. Run a temporary ground with alligator clips from the general area to the engine block to see if there is any difference. Less than $5.00 to make one from auto store parts. Comes in handy for other things later, other electrical testing, punk rock jewelry, emergency zipper repair and barbequeing of crayfish.

I would think a bad ground would keep the light on at all times or make it a more sporadic problem. This seems to happen every time I start the car from a cold start. I was thinking of going with a lighter grade oil such as 10W40 for the warmer months but I've always heard it's good to run the 20W50 in hot climates for better protection. That darn light makes me nervous I may have a problem and I can't help but fear I may be damaging my bearings and other internals, although it's only a few seconds on initial startup.
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74 Tii
01 S2000
06 Tacoma
"Why Johnny Ringo, looks like somebody just walked ova your grave" -Tombstone-Val Kilmer

1. The pressure switch is at the far end of the oil distribution system, way up in the cylinder head, so is the last place pressurized oil reaches when you start your engine.

2. A worn engine (bearings, valve train) will bleed off pressure on its way to the pressure switch at startup and allow increased drainback when you turn the engine off.

3. The heavier the oil, the faster you get pressure.

4. If you have a VDO gauge with dual terminals that allow gauge and light, that switch is set to illuminate at 15 psi, while the factory switch illuminates at 7.5 psi.

5. If you want real peace of mind, temporarily connect a mechanical gauge to the system and check your oil pressure.

cheers
mike
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'69 Nevada sunroof--"Wolfgang"--bought new
'73 Sahara sunroof-- "Ludwig"--mine since '78
'87 eta E30 coupe--"Johannes"
+ Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette)...
and Kermit, the Bugeye Sprite

mike wrote:

1. The pressure switch is at the far end of the oil distribution system, way up in the cylinder head, so is the last place pressurized oil reaches when you start your engine. 2. A worn engine (bearings, valve train) will bleed off pressure on its way to the pressure switch at startup and allow increased drainback when you turn the engine off. 3. The heavier the oil, the faster you get pressure. 4. If you have a VDO gauge with dual terminals that allow gauge and light, that switch is set to illuminate at 15 psi, while the factory switch illuminates at 7.5 psi. 5. If you want real peace of mind, temporarily connect a mechanical gauge to the system and check your oil pressure. cheers mike

Thanks for the thoughts Mike. Why I was thinking of a lighter grade oil I don't know. My 74 is only equipped with the "idiot" or warning light and no gauge. Your final suggestion is probably what I need to do to put any fears to rest but I don't have a mechanical gauge. Probably wouldn't be a bad investment.
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74 Tii
01 S2000
06 Tacoma
"Why Johnny Ringo, looks like somebody just walked ova your grave" -Tombstone-Val Kilmer

"Your final suggestion is probably what I need to do to put any fears to rest but I don't have a mechanical gauge. Probably wouldn't be a bad investment."

Most repair shops have a "universal" mechanical gauge that can be hooked up temporarily to check oil pressure...cheap peace of mind insurance...

mike
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'69 Nevada sunroof--"Wolfgang"--bought new
'73 Sahara sunroof-- "Ludwig"--mine since '78
'87 eta E30 coupe--"Johannes"
+ Fiat Topolini (Benito & Luigi), Renault 4CVs (Anatole, Lucky Pierre, Brigette)...
and Kermit, the Bugeye Sprite

I'd like to piggy-back on this thread with a question about the warning light. Mine doesn't come on when I turn on the ignition. I've got a brand new engine and the shop that installed it checked that the pressure guage and the actual pressure were OK, and, I pulled out the instrument cluster and switched the bulb w/ the alternator light and the bulb is fine. Is a possible source of the problem a break in the printed circuit board on the back of the instument cluster. I appear to be getting power from the new pressure guage as far as the big plug @ the cluster. Tips, as usual, appreciated.

Bob Napier

Sarki wrote:

I've noticed that when I start my car, especially after it sits for a few hours, the oil light on the dash stays on for about 3-5 seconds. Wondering if that's "normal/common" or if I need to look into this further. If it's not normal, what would my next step be. Oi level is good, 20W50 Castrol with Mahle filter.

i think its normal. my e21 does the same.
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69 02 sahara - project
76 02
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