I have a 94 Pontiac Grand Am with the 3.1 V6. Motor runs excellent but the oil pressure is doing weird things while I drive. It will vary from about 40 psi to 25 psi and back and forth at random. Some have suggested that the oil passages are gummed up and that the motor should be flushed, but the first 100K miles were Mobil-1 and now I am running Amsoil. Anyone familiar with this issue? Recommended flush if required?
Pontiac 3.1 Erratic Oil Pressure
- Thread starter vettenuts
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Vettenuts, your symptoms are classic for a clogged oil pump pick-up screen. You might try draining the oil and scraping the screen with a piece of bent piano wire (through the drain hole). If residue comes off, then the screen is probably clogged.
First make sure the trouble is not in the oil pressure gauge sender. Make sure the wire going to it is clean and tight. It might even be worthwhile to replace the sender; most are under $10.
First make sure the trouble is not in the oil pressure gauge sender. Make sure the wire going to it is clean and tight. It might even be worthwhile to replace the sender; most are under $10.
Before you go & drop the oil pan, check the oil pressure sending unit. I believe it is on the passenger side of the engine on the top side between the intake & heads. Any oil leaks on top of the engine from any sensors you've noticed? Even if there aren't any, it can still cause exactly what you've described.
If you have a mechanical oil gauge, remove the oil pres. sending unit & check the oil pres. by screwing the mech. gauge where the sender goes. Start the engine. If you have steady oil pressure, change the sender. Or, if you don't, just change the sender out. It doesn't cost much.
That would be the 1st thing I'd check out.
Steve
If you have a mechanical oil gauge, remove the oil pres. sending unit & check the oil pres. by screwing the mech. gauge where the sender goes. Start the engine. If you have steady oil pressure, change the sender. Or, if you don't, just change the sender out. It doesn't cost much.
That would be the 1st thing I'd check out.
Steve
Thanks, I will try the sending unit and maybe a cleaner prior to my next oil change. Always had synthetics so I was hoping something like a clogged screen would never happen. It doesn't help that half the passenger side suspension has to be removed to get the pan off
The bypass piston in the oil pump can also cause this .
Search Mellings + oil pressure fluctuation ...their website has some good oil pump tech info or did a couple years back when I was last there
Search Mellings + oil pressure fluctuation ...their website has some good oil pump tech info or did a couple years back when I was last there
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