Please Help! Oil light on a 1990 Mazda Pickup B2200 keeps coming on despite repairs

Maintenance/Repairs
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1

The oil light came on in my mazda pickup. So the mechanic put in a new oil sending unit, spark plus, wires, distributor. $250. Two days later the oil light came back on. So the mechanic put in new rod bearings, main bearings, oil pump, water pump, timing belt, valve cover basket, and oil filter (and oil, of course). $1300. Two days later, the oil light is BACK ON!! What is going on??

2

The key question that anyone will need to know is whether or not the mechanic (or anyone) has checked the actual oil pressure with an external & reliable gauge.

3

The mechanic said he was doing it before I picked it up. I’ll call and verify as soon as they open.

4

So the mechanic put in a new oil sending unit, spark plus, wires, distributor. $250.

If he changed the sending unit, that means he thought the pressure was fine but the sending unit was wrong. Did he actually verify the oil pressure before replacing the sending unit? If not, I would stop going to this mechanic. The plugs, wires and distributor might or might not have been needed, but had nothing to do with the oil pressure light.

So the mechanic put in new rod bearings, main bearings, oil pump, water pump, timing belt, valve cover basket, and oil filter (and oil, of course).

So now he thinks you have low oil pressure. Did he actually verify it? Did he replace the bearing seals when he replaced the bearings? The timing belt, water pump and valve cover gasket might or might not have been needed, but have nothing to do with low oil pressure.

I would be having second thoughts about the mechanic at this point…

5

Try cleaning the electrical connector going to the oil pressure sending unit to see if possibly it’s dirty and not getting the correct signal. Also make sure the electrical connector is fitting tight on the sending unit. The mechanic should have verified low oil pressure prior to doing an overhaul of the engine. Is the oil light flashing all the time or just at idle? If it’s just at idle maybe the idle speed is too low.

6

This may seem like a silly question, but has anyone checked the level of the oil using the dip stick?

7

The oil pressure sender is a simple on/off switch. With low pressure the switch closes & grounds the voltage from the idiot light & the light comes on…
Try removing the wire from the sender. If the light stays on look for a short to ground in the wire

8

Does the light come on only at idle?