oil pressure light pulsating on and off

[trac209]

Most times it's worn bearings that will cause oil pressure loss before the oil pump will wear to that point. Then Engine can and will still run as normal until the clearance becomes to much to keep the crank happy.

[1972BlueC20]

Ok i'll get a gauge tomorrow and report back my findings.


Thanks!

[1972BlueC20]

UPDATE!

Ok guys, I hooked up a dash mount style oil pressure gauge today that I got from the parts store. It wasn't expensive but it's not meant to be permanent just to give me an idea of my actual pressure. They didn't sell any kind of pressure tester tool so I went with that.

I got it all hooked up and the pressure went straight to 30-32 psi cold. It stayed there within 2 psi even after it was completely hot. When I got my wife to go through the gears it barely dropped to like 29 or 28 pounds. I turned the truck off several times and it would immediately drop to 0, then upon restart it would go right back to around 30 PSI.

Is this a normal oil pressure? It would also shoot up to about 40-45 ish when I would rev it hard.

When I unplugged the plug on my oil sending unit, I found that the inside of the plug was covered in fresh oil (I just changed my oil). After I pulled the sending unit out, it was also covered in fresh oil. Maybe it cracked or was defective?? Could this cause the oil light to flicker and pulsate?? It wasn't leaking bad enough to cause an oil leak that made it to the ground anywhere, but it was definitely covered in oil.

My next step is to clean all the oil from the inside of the sending unit plug, and then reinstall a brand new sending unit that I just bought and make sure it's nice and snug. Hopefully this oil pressure gauge was accurate or atleast in the ballpark....if so I think im good to go.....maybe the oil inside the plug was causing the signal to short out or something causing the idiot light to flicker...


what do you guys think???


I'm working on the truck now, so any responses tonight will be greatly appreciated!!

[88Ironduke]

Oil in the connector/plug is bad in any oil sensor and it must be replaced. I wouldn't have thought it possible (had to see it to believe it) but oil can actually short out the plug and start popping fuses. Never thought of oil as a conductor. Your oil pressure sounds normal, I would be happy with those numbers any day of the week. Good job troubleshooting and not trouble guessing.

88Ironduke

[trac209]

Your oil pressure is fine I'd say sending unit is a dud and either get another or use a gauge.

[JJLT1]

x2 the oil pressure is good..
I would just keep the gauge..

[1972BlueC20]

Thanks guys for all your help!

Love this site!


So after getting everything back together last night, and installing the new oil sending unit and cleaning all the oil from the inside of the sending unit plug my idiot light has stayed off now for about 2 hours of driving time from last night and this morning on the way to work. Normally the idiot light was coming on every time I drove it, so this is very promising!

I will eventually install gauges or convert to a factory gauge cluster later when I eventually hop up the engine and redo my engine compartment.

[truckdude239]

chevy normal min is 20 psi at idle but evey i run my old 327 at 10 psi for years

[davepl]

Yeah, I've had engines live for decades at 12psi. I'd prefer more, but as long as the bearings are floating, it's sort of a binary thing - turn a bearing or not.

[geezer#99]

Originally Posted by davepl

Yeah, I've had engines live for decades at 12psi. I'd prefer more, but as long as the bearings are floating,

Bearings don't float!!
Journals do!!

[davepl]

Originally Posted by geezer#99

Bearings don't float!!
Journals do!!

They do when you spin 'em, at least for a microsecond or two. But yes, you're absolutely right, I wrote that one backwards.