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More info, please Posted by Ari [Email] (#2847) [Profile/Gallery] (more from Ari) on Tue, 20 Jan 2009 18:29:05 In Reply to: no oil pressure, Leanne Cota, Mon, 19 Jan 2009 20:42:51 Members do not see ads below this line. - Help Keep This Site Online - Signup |
First, how do you know you don't have oil pressure? How and where did it happen? What did you do when you found out?
I assume the oil light came on. Have you actually measured the oil pressure? Did you drive it any after the light came on? If the engine was at idle or running with the light on, how did it sound?
The oil light on doesn't necessarily mean no oil pressure - it can be a bad sensor, or just a shorted wire. If you measure no or low oil pressure, that's a different story. If the engine sounded very 'clattery' - then I'd believe low oil pressure. But if the engine was normally quiet, I'd suspect a sensor problem.
Yes, the oil pump is on the crank, hidden behind the main pulley. I also don't suspect the oil pump. They can lose efficiency over time, but they don't just stop working. The pump is two, big, beefy gears. Yes, it can wear and the pressure drop slowly. But suddenly not work, no. There is a pressure regulating valve - if that breaks, you can lose oil pressure. I'd believe a broken valve spring before I'd believe a pump suddenly stop working.
Possible issues - bad oil pressure sensor, bad wire to sensor, bad oil presuure regulating valve, clogged oil screen, and yes, worn oil pump. Yes, you've changed the oil regularly, done everything right. Engines can still sludge. It's not a guarantee, but a possibility.
Step 1 - determine if you really have no oil pressure. Visually check the wire from the sensor - if it's grounding out to chassis, fix it. Stick a known good oil pressure gauge on the engine, and actually measure the oil pressure. You can let the engine start and idle for a few seconds - it won't do any more damage. If you're already done this, my apologies for being too simplistic. I've had five low oil pressure indications in my life, four of which were bad sensors. One was low oil pressure - something about a bolt driven through the oil pan, and no oil.
No oil pressure and low oil pressure are different things. An oil pressure switch comes on typically around 7-8 psi. That's not very high, but hot oil on a hot day at idle, oil pressure can be that low. It can be 40 psi cold.
Step 2 - if you really don't have oil pressure, check the oil pressure regulating valve. That's a lot easier to access than dropping the pan.
Step 3 - if the oil pressure valve seems OK, snake a wire down the dipstick and poke around in the oil pan. If the wire comes back gunked up, drop the pan and see if the oil pickup is clogged.
Step 4 - if the oil pan is unsludged (unlikely), pull the oil pump and check the wear. Leave the oil pan off, because if you really have low oil pressure, you're going to want to check the bottom bearings.
But come back with some more information - what happened,leading up to and afterwards? How do you know there is no oil pressure?
Don't assume the worst. Today is a good day.
posted by 192.249.4...
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