90 Corolla Oil Pressure Switch

We've had the oil light come on, while driving, and stay on, untill the revs go over 3000RPM. To try and fix this problem, dad has changed the oil pump, and still the same problem. So now he's changing the Pressure switch, and comes to find out that the one off of his 90 Corolla wagon, same engine family, same year same everything, except his was made in June and it is an Automatic. The one that has the problem was made during July, and is a standard. is different. They both fit, and the one that we know works, turns the light off, but the one that we think is broken, turns it on. They're different in size, and the diameter of the hole. one is a pin sized one, and the other is about 2 times bigger!! Will they both work?? Please let me know!!

CRC

Reply to
72Capri
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Your dad should borrow or rent an oil pressure gauge, hook it up to the port for the oil sender, and measure oil pressure at idle and at higher RPM. If the oil pressure is within specifications, then you know you have a problem with the sender, warning light, or wiring in-between.

If oil pressure is too low and you know that the replacement oil pump is good because you used a feeler gauge to measure crescent-to-body clearances, then there is an internal problem in the engine like blockage somewhere, clogged oil pickup, or excessive clearance in the crankshaft bearings.

Unplug the wire connector from the oil sender and with an ohm meter or continuity tester, check for continuity between the terminal on top of the sender and the sender body. With the engine stopped, there should be continuity and with the engine running, the circuit should be open (no continuity). If this is not the case, the sender is bad. Rather than using a 17 year old replacement part, my recommendation is to use a new oil pressure sender after checking.

Reply to
Ray O

So the pump has been changed, and there was no difference,(now before people get worried that we're going to ruin the engine, there was no change in engine sound, temperature, fuel consumption, everything was the same. So the switch had to of been faulty) but my parents took the car on a 4 hour hockey trip with my brother, and it did the trick!! The light is out, and hasn't been on since. Thanks for looking. :D

CRC

Reply to
72Capri

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