Oil pressure light... After filter change

[jrobie79]

1Car was off the road for 5 years, engine on a cart for about 8 months, 1 if those was outside with a tarp over it... pretty much fired right up, only drove it in and out of the garage for about 3months while I put it all back together. Finally drove it for the first time a few weeks ago, zero issues. I changed the oil after about 300 miles, figured any residual rust and whatnot would be in the filter. Mobile 1 15W-50, but I didn't have a new filter at the time, so I used the old one for about a week. Changed the oil filter on Sunday with a brand new MANN. Noticed the cluster oil pressure light is illuminated when I start it. It's not a constant brightness, it dims and lights back up continuously. Dims when I give it throttle, but never goes fully out. If I open the oil cap oil still splashes out, so it would appear oil is still reaching the head... First thought was faulty sensor, but I'm not really sure.

[82eye]

sounds like the pump is failing and the sensor is doing its job.

edit: you'll want to get a gauge on it to test if it is the pump or the sensor reading wrong. in practice it's almost never a sensor.
did the pump get packed with build grease or primed after the rebuild? m42 pumps are notorious for not priming.

[TobyB]

The dimming thing makes me suspect an electrical issue,
but yeah, I ALWAYS go straight to the mechanical oil pressure
gauge first, and then, once there's 50 psi, then start troubleshooting the rest of it.

t
oil pressure is life.

[jrobie79]

sounds like the pump is failing and the sensor is doing its job.

edit: you'll want to get a gauge on it to test if it is the pump or the sensor reading wrong. in practice it's almost never a sensor.
did the pump get packed with build grease or primed after the rebuild? m42 pumps are notorious for not priming.

I didn't rebuild the engine. Just the car. And I have been driving it every 4 or 5 days for the past 3 weeks, put about 600 miles on it before this happened. What's the easiest way to get a gauge on there? Just take the sensor out and use an adapter?

[82eye]

I didn't rebuild the engine. Just the car. And I have been driving it every 4 or 5 days for the past 3 weeks, put about 600 miles on it before this happened. What's the easiest way to get a gauge on there? Just take the sensor out and use an adapter?

i've never had to do one on an m42. i know it's been done here before, might have to tee in an oil dist block. would just run the gauge temporary under the hood for diagnosis.

edit: if the light can be trusted it's indicating a low pressure on start up which is really hard on the engine.

[jrobie79]

There's a threaded hole on the front of the filter housing. Gonna put a gauge in there tonight. I'll see what happens

[jrobie79]

Looks ok to me. Time to swap the sensor

[82eye]

Looks ok to me. Time to swap the sensor

best news yet.