I recently picked up an 02 WRX with 275k miles.
Once I noticed that on a cold start, the oil light was on very faintly and faded off as it got up to temp. When I asked if this was a normal thing or something bad (I don't know Subarus at all) I got "Mine did that right before it spun a bearing, you probably shouldn't rev it too much" 
It's only done this once but, feeling a little paranoid, I decided to test the oil pressure. At the oil pressure sensor under the alternator I got the following readings.
Cold start (idling):
Idling at temp:
Revving at temp (no load, boost, etc)
Curious if you guys think this seems like relatively "healthy" oil pressure. I don't know what weight oil is in it currently (forgot to pick some up to change it).
Holy crap! Not an expert, but thats a lot of pressure at both points.
Teh E36 M3 wrote:
Holy crap! Not an expert, but thats a lot of pressure at both points.
What he said. I don't know jack about Subarus but I think the older VW's had a light/buzzer for HIGH oil pressure as well as low. That pressure looks way higher than anything I've owned.
I can't believe a WRX made it to 275K miles!
I'd say the hot revving pressure is the only one that looks like it could possibly be healthy
Edit: Do you know if it has the proper viscosity oil in it? This looks like it could be an engine running too-thick oil.
Seems high.
Could be a stuck relief valve.
Wonder if the oil pump bypass is stuck closed?
Maybe a wee bit high. From Alldata:
At 800 rpm or more 98 kPa (1.0 kg/cm2, 14 psi)
At 5,000 rpm or more 294 kPa (3.0 kg/cm2, 43 psi)
These are minimums, so it may not be a mile off if its got 20W50 in it.
Worry about it when it balloons the oil filter.
I had a Mustang with the 2V 4.6L in it. Was running the Melling 4V high volume oil pump with the billet gear. I had 90psi cold idle oil pressure even with 5w30.
Called and talked to Melling about it. While they agreed it seemed a bit high, they weren't overly concerned. Again, the only real suggestion was that the pressure relief plunger could be stuck. But I wasn't willing to tear the motor down again to find out.
I say check it again after an oil change so you know what viscosity is in there. Though I don't think that's going to make a big difference.
That's what my race rotary is built to produce. Seems pretty high for a stock WRX, like somebody threw straight 50 weight in it to stop you from hearing a rod knock.
