Oil pressure light flickering on

[sweetp01569]

I just changed my oil and used 10W-40 Castrol oil (not synthetic). I also replaced the copper crush ring on the low oil pressure sensor for the dash light. Now the light flickers on when I seem to rev the engine as I shift into gears, unless the wire connector happens to be intermittently shorting and causing the light to go on. The pressure gauge on the dash reads just under 80 psi.

I am also not sure of the weight of the oil that I just changed out, as it was done in a shop a couple years back. It may have been synthetic, as I have used the Mobile 1 synthetic before that. The oil level is correct on the stick and there are no visible leaks. Could the 10W-40 be too low a weight and cause the light to come on and off, or do you suspect a short? I have also seen on this forum where 20W-50 is used and has corrected the pressure light problem. The manual does say that 10W-40 is acceptable. I live in MA, so the temperatures varies. Today it is about 80 deg F.

Any thoughts would be appreciated. I think I'll check the wire tomorrow. I have replaced a piece of it in the past so it's not crispy.

Thanks,


Paul

[Bitsyncmaster]

Most of those low pressure switches need a good contact to the engine block. If the sensor has one wire it needs that block contact. Just give it some more twist to make more contact.

[sweetp01569]

Thanks, Dave,

I'll give that a try tomorrow and let you know if that takes care of it. So in your opinion my oil weight of 10W-40 should be ok?

Paul


Most of those low pressure switches need a good contact to the engine block. If the sensor has one wire it needs that block contact. Just give it some more twist to make more contact.

[DMCMW Dave]

Most likely the wire to the sender is shorting against the block somewhere. The light should be on solid with key on/engine off, and should be off with the engine running. If there is a bad contact it won't light up Key On/Engine Off

OR - you really have bad oil pressure and a gauge/sender that is wrong. Doubtful.

[sweetp01569]

I hope it's just an electrical contact issue, since I took that out to replace the copper washer. At least my leak there is fixed! Nice and dry around the sensor, where before it would keep weeping oil and dripping occasionally.

Thanks again!


Most likely the wire to the sender is shorting against the block somewhere. The light should be on solid with key on/engine off, and should be off with the engine running. If there is a bad contact it won't light up Key On/Engine Off

OR - you really have bad oil pressure and a gauge/sender that is wrong. Doubtful.

[Bitsyncmaster]

Most likely the wire to the sender is shorting against the block somewhere. The light should be on solid with key on/engine off, and should be off with the engine running. If there is a bad contact it won't light up Key On/Engine Off

OR - you really have bad oil pressure and a gauge/sender that is wrong. Doubtful.

+1
I should have looked at the schematic. The switch will ground to turn on the light so you're correct, it must be the wire shorting.

Oil weight should not affect that switch. Think most turn on under 5 PSI.

[DMCMW Dave]

+1
I should have looked at the schematic. The switch will ground to turn on the light so you're correct, it must be the wire shorting.

Oil weight should not affect that switch. Think most turn on under 5 PSI.

Agreed - If the light turns on due to low pressure, your engine is in deep weeds. . . . .

[sweetp01569]

Although I did change the wire a while back, I didn't use one with thermally rated insulation. It was crispy with copper exposed and thus shorting against the engine.

I replaced it with a similar thermally unrated wire, but had some heat shrink tubing to sleeve over it. I'm not sure if the heat shrik tubing is rated for high temps or not, but worst case, if it burns through again, I'll replace it with proper wire.

The light does not illuminate now, so problem fixed. Thanks again!

Paul



Agreed - If the light turns on due to low pressure, your engine is in deep weeds. . . . .

[David T]

Go to an auto store or performance shop and get some fire sleeve materiel to slip over the wire. It does get really hot in there and ordinary insulation cannot handle it.
David Teitelbaum

[kings1527]

Of course, I've now developed a slight oil leak at the sensor. It looks like it's tough quarters to get in there with a wrench or socket without taking the exhaust bracket off or the exhaust off completely.

Any easy way to do this? Crow's foot, maybe?

Thanks!

[DMC Fanatic]

I just replaced mine a few weeks ago. I didn't have to remove anything and just used a 3/8 socket wrench with a swivel. Make sure you soak it with PB blaster first.

[kings1527]

I just replaced mine a few weeks ago. I didn't have to remove anything and just used a 3/8 socket wrench with a swivel. Make sure you soak it with PB blaster first.

Perfect. That's just what I was looking for. Thanks!