Oil Pressure switch

[SteinOnkel]

Hey guys,

just wondering what the pressure is below which the oil light comes on with a 1978. It only has the dummy light.

Thanks
Steiny

[18Fiatsandcounting]

Steiny, this is just a guess, but I'm thinking 5 to 7 psi? On my cars that have had a pressure gauge and a low pressure light, the light only comes on when the gauge is flickering right above the zero mark on the gauge.

I'm also thinking that this switch is not a precision device, so the "actuation pressure" could vary with age, quality, manufacturer, oil viscosity, etc. Certainly less than 10 or 15 psi, and more than zero (one would hope).

-Bryan

[SteinOnkel]

Ah, okay, that kind of confirms my suspicion.

Yesterday I was on a slight incline and the light flickered at idle. Leave it to me to drive a 42 year old vehicle and not check the oil level

Luckily it was only for a few seconds, as there was a gas station right there. I'll be measuring oil pressure later today, but the engine seems happy.

Cheers
Steiny

P.S: On my VW, the light come on below 1.1 bar. Which is a bit pessimistic. It'll come on if you lug the hot engine just a liiiiitle bit.

[18Fiatsandcounting]

Yesterday I was on a slight incline and the light flickered at idle. Leave it to me to drive a 42 year old vehicle and not check the oil level

On many of my Fiats, the oil light has flickered at idle, especially when the engine is really warm. I can't say that this is normal, but I also don't think it's a serious cause for concern. Flickering when hot at low idle = OK. Steady light with a normal idle = not OK.

Turn up your idle to 1500 and that will solve the problem!

-Bryan

[SteinOnkel]

Yesterday I was on a slight incline and the light flickered at idle. Leave it to me to drive a 42 year old vehicle and not check the oil level

On many of my Fiats, the oil light has flickered at idle, especially when the engine is really warm. I can't say that this is normal, but I also don't think it's a serious cause for concern. Flickering when hot at low idle = OK. Steady light with a normal idle = not OK.

Turn up your idle to 1500 and that will solve the problem!

-Bryan

This message supported by the Department of DPOs

[18Fiatsandcounting]

This message supported by the Department of DPOs

Awww, Steiny, I'm just messin' with you, man! At least I didn't advise you to go buy some SAE threaded bolts and force them into metric threads with an air impact wrench.... Now THAT would definitely move me into DPO space.

-Bryan

[SteinOnkel]

This message supported by the Department of DPOs

Awww, Steiny, I'm just messin' with you, man! At least I didn't advise you to go buy some SAE threaded bolts and force them into metric threads with an air impact wrench.... Now THAT would definitely move me into DPO space.

-Bryan

What monster would do such a thing!?!?

[SteinOnkel]

Following up on this. Light flickers all the damn time now, so decided to measure what's going on.

Cold Idle (1100 rpm): 3.9 bar
Cold High Idle (3000 rpm): 6.0 bar

Hot Idle (850rpm): 1.7bar
Hot High Idle (3000rpm): 4.2bar

So that's phenomenal for a 42 year old machine

Going to replace the switch, but how much do you want to bet that it's due to some wonky wiring courtesy of the dpo?

Cheers
Steiny

P.S: Switch I pulled out is 0.2-0.4 bar.

[18Fiatsandcounting]

Following up on this. Light flickers all the damn time now, so decided to measure what's going on.

Cold Idle (1100 rpm): 3.9 bar
Cold High Idle (3000 rpm): 6.0 bar

Hot Idle (850rpm): 1.7bar
Hot High Idle (3000rpm): 4.2bar

So that's phenomenal for a 42 year old machine

Going to replace the switch, but how much do you want to bet that it's due to some wonky wiring courtesy of the dpo?

Cheers
Steiny

P.S: Switch I pulled out is 0.2-0.4 bar.

Your numbers look good to me Steiny, and yes, when in doubt, always blame the DPO!

But seriously, I no longer believe the "low oil pressure indicator light" after 50 years. Low oil pressure means your bearing clearances are opening up and getting more oil flow (thus reducing the pressure), and that's a good thing, right?

But, I totally get it that zero oil pressure is not a good thing.... Except when the engine isn't running, of course.

-Bryan