oil light indicator

[akble]

swapped engines on my Q-45- old engine was bad and got used engine from another club member with 90k and supposidly good running order.It starts and runs fine however initially the oil light came on after a few seconds and would blink rapidly. Changed the oil again and it seemed to get better but still came on. Ran some engine cleaner in oil and changed along with filter again.Now engine light stayed off and so did Check Engine light. Let run at least 30 minutes and light drive around town. No problem. First trip out of town started blinking rapidly about 10 minutes into trip @ 60mph. Then changed to solid before I got back to town. When stopped it went off but would return when started. From cold it stays off.Oil pump? and other suggestions? seemed to run fine even when it was blinking fast- loose wire or short? sensor? Any ideas would be great help.Thanks!

[gs14racer]

i would think, if it goes like other nissan engines, that shortly after the oil light comes on the rods start to knock, check the sensor or the wiring imo.

[Q45tech]

Remove the oem 3 psi oil pressure switch and actual measure the oil pressure. Create a cold vs hot graph referencing coolant temp and time since start.

The oem MINIMUM is 14 psi at very HOT IDLE RPM. AC and headkights on!

650 rpm

EXACT RPM IS VERY IMPORTANT, look at what happen in drive not at the 100 HIGHER RPM IN PARK

Worst case conditions are new oil and new filter as the viscosity increases with mileage and the dirt in filter increase pressure differential drop.

Interesting to monitor PSI at highway cruise in summer to see how low it can go at 2,000 rpm [60 mph].

You can blend [same brand and type] viscosities of oil in Summer to stay above minimums say 10w40, 11w36, or 12.5w45.

[elwesso]

with all that driving on low oil pressure, id suspect it might be too late...

However, I suspect the oil pan is dented. im sure the owner set the engine on the oil pan and the pickup is right on the bottom... So even if its dented the smallest bit it will cause low oil pressure... Common to see this on swaps on Q45, Z32, and other nissans with the stamped steel pan.

[Q45tech]

My 322,000 mile engine is down to 12 psi [absolute worst case at 100F ambient] with 10w30 Mobil One so I have had to go to 5w40 to maintain oem spec in summer.

[akble]

by "too late" what am I facing? engine ruined? it still runs fine with not knocking or noticeable noise!

[akble]

spoke a little early- todya upon start up is knocking pretty good- looks like I am faced with swapping engines again, rebuilding or selling as is- black 92with only 118K and pretty nice shape- was owned by 94 year old widow- honest~

[elwesso]

you might get away with replacing the bearings if you're lucky...