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Can old or thin oil cause low engine oil pressure?
1997 BMW 540i /4.4L/6speed.
The warning light ONLY comes on at idle and only after the car warms up. I check the oil level before and after I drive and it doesn't seem to change. The dipstick reads right at the MAX fill line. I have seen this question all over the internet, but it appears the issue remains unresolved. The engine runs silent, no ticking. Any ideas?
3 Answers
- paul hLv 76 years ago
Old or thinner grade oil can cause weak oil pressure at idle/warm engine...if the oil is too thin, it can slip past the rotors in the oil pump which reduces pressure at low rpm's. Try changing oil with proper grade...or slightly thicker grade oil for a high mileage engine... and see if it improves idle oil pressure. If not, it could be other issues...worn pump, weak pressure spring in pump bypass port, bad oil pressure sensor or dash gauge etc..A shop can hook up a mechanical gauge to the oil pressure sensor port and see if pressure is indeed low or not...most engines run around 15-20 psi oil pressure at idle and raises 10 psi for every 1000 rpm's to a high limit of around 60-80 psi..
- Anonymous6 years ago
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