QUOTE (Bull Geek @ Nov 15 2009, 11:23 AM)
sfontain was having a similar issue IIRC
...might want to check some of his threads out. He has a 02 Vulcan as well.[/b]
Hah, I was just going to chime in on this.
We have exactly the same model year and engine, and I had the same trouble with 5W-30 synthetic (SuperTech from Wal Mart). I went to 10W-40 conventional and the light disappeared after about 20 minutes of running the engine. (Why it wasn't instant, I can only guess.)
Do check your oil level, but if it's only happening at idle then I'd say that's probably not the issue.
If it happened immediately after changing the oil, also spend the $4 and put on a new oil filter. This will take you like 3 minutes.
You can replace the pressure sending unit if you really want to blow $30 at a dealer (you can get this part for $16 on Amazon; free shipping if you spend at least $25 or have Amazon Prime). But I'm going to go out on a limb here and suggest that it's RARE for these things to go bad.
IMO, your money is better spent on an oil pressure gauge. $18 for SunPro from Advance, or $35 for Auto Meter on Amazon. I have both. The Auto Meter reads lower on the low end of the range. Either way, if your gauge shows 8 psi
at idle, that's going to be a hell of a lot worse than if it's showing 13, and you'll have a little better idea how bad your problem is. If the light is only flickering, it stands to reason with me that you have a wear or clog issue slowly developing that is only going to get worse, but how quickly it will progress is purely speculation.
Odds are, you do actually have low pressure at idle. I would switch back to 10W-40 and consider tearing apart your engine to check the oil pump and pickup screen and bearings; if you don't want to do that yourself (and it will be a pain in the ass), it might be time to consider getting rid of this car. A dealer will charge you ~$500 to change the oil pump, and $1000-$2000 to change the rod bearings. Just FYI, my opinion is 10W-40 is perfectly fine for this car despite that it's spec'ed for 5W-20, so long as you don't live in an extremely cold climate. Your fuel mileage may drop a little, though.
In case you or someone else does take apart the engine, please let me know what you discover. I'd like to know if this is more likely bearings or the oil pump/screen.