Three-and-a-half years later, and my sending unit failed...again.
These things are pure junk. Yesterday it indicated "zero" oil pressure when restarted after mailing a package at the Post Office. No lifter clatter, no rod knock...I drove it 10 or 15 miles to get the thing home.
I went to NAPA, Advance, and O'Reillys on the way home. None of them even show a part number for the sending unit on their computer. They list the wiring connectors, and the oil pressure switch that drives the fuel pump, but not the sending unit for the gauge. It's as if whoever compiles the list of parts to display on "the computer" forgot about that application. Very strange. The guy at Advance went to the paper catalog, found Advance # S6649, but this is the big gold/copper colored one that doesn't actually fit. It's made by BWD--or at least it is packaged in a BWD box.
So I pull the connector off the top of the sending unit, and the gauge goes to the high end of the scale. Gauge works. I rip the sender off the engine, connect an OTC pressure gauge...and I have my typical 50 psi. CONFIRMED: Not an oil pressure problem at all--it's a sending unit problem.
Doing some more on-line research,
BWD S4320 seems to be the correct one. It has a silver case, and green paint around the end with the electrical connector.
http://weblink.carquest.com/acl/?mfg...rtNumber=S4320
The NAPA / Echlin crossover from that number is
OP6729. AutoZone sells it as
PS150. Autozone is by far the most expensive, at $36. The other brands are less than $21.
NAPA warranty is 3 years, 36K miles.
Advance says "Limited Lifetime warranty"
O'Reillys warranty is "Limited Lifetime"
AutoZone warranty is "Limited Lifetime"
Advance took over the local CarQuest, we'll see if they'll honor the warranty on the failed sending unit.
None of these stores locally actually stock the part, so I won't have one to verify and install for a few days.