What do you do if you dont know your oil pressure?

[45ACP]

Quick question relating to any engine.. If you were inclined to go the "thinnest you can get it" route, but you did NOT know your car's oil pressure (no gauge,) would satisfaction that the OP idiot light isnt coming on be satisfactory enough to calm your experiments with going thinner than a 30-grade, say, to a 20-grade oil?

I presently mix 30 and 20-grade oils in my car, half and half, but i have no idea the oil pressure. Im rather curious as to how my "hydrodynamic wedge" is holding up, since i decided to be brave and go the very razor's edge thinnest i could go.


What is to be made of my lack of an oil presure for a point of reference? Thank you.

 

[Hokiefyd]

Well, they say that you want 10 pounds of pressure for every 1,000 revolutions per minute. The idiot light just illuminates if you go below the lowest trip point it has, so it really doesn't tell you much about the working oil pressure. Frankly, even many factory oil pressure gauges don't do a good job of that either. Without knowing your vehicle, miles, condition, etc, I would say that your idiot light staying out is one good thing, but it doesn't really tell you the whole story either.

 

[45ACP]

Originally Posted By: Hokiefyd
Well, they say that you want 10 pounds of pressure for every 1,000 revolutions per minute. The idiot light just illuminates if you go below the lowest trip point it has, so it really doesn't tell you much about the working oil pressure. Frankly, even many factory oil pressure gauges don't do a good job of that either. Without knowing your vehicle, miles, condition, etc, I would say that your idiot light staying out is one good thing, but it doesn't really tell you the whole story either.


Thats exactly where im at right now....................... .............and also why i mix half 5W20 with half 5W30, so i can be in the "light 30" range more like "lightest 30" and have peace of mind that way. It might be the most peace of mind i can get without stepping up oil weights, everything i read tells me that as long as my hydrodynamic wedge exists, i dont have to go any thicker, and that the hydrodynamic wedge is obtained in the weight of oil spec'd for my engine. Hence, the mix................

So the thinner stuff really "lubricates better," eh? Still trying to get my head around that one, somewhat. So far my engine likes it.. i do the worrying for it. :LOL

 

[d00df00d]

Originally Posted By: 45ACP
Quick question relating to any engine.. If you were inclined to go the "thinnest you can get it" route, but you did NOT know your car's oil pressure (no gauge,) would satisfaction that the OP idiot light isnt coming on be satisfactory enough to calm your experiments with going thinner than a 30-grade, say, to a 20-grade oil?

No. AFAIK, the idiot light is for when oil pressure gets below the safe range for idling. That threshold is WAY too low for normal driving.

 

[hattaresguy]

That's the risk you take experimenting, or you can just follow the factory specs and go on their engineering data instead of pioneering your own.

 

[hate2work]

Originally Posted By: hattaresguy
or you can just follow the factory specs and go on their engineering data instead of pioneering your own.


This is what I would recommend.

 

[45ACP]

Originally Posted By: hate2work
Originally Posted By: hattaresguy
or you can just follow the factory specs and go on their engineering data instead of pioneering your own.


This is what I would recommend.


I can respect that, but this site is ALWAYS talking about going thinner than the recommended oil weight by a vehicle manufacturer. (Please correct me if i am wrong.) Isnt that what Motor Oil 101 generally alludes?

My car runs well on the 5W20/5W30 mix i would like to have the peace of mind that my engine will be ok. All i have is the butt dyno, and thats not the same as a a gauge.

 

[someguy]

Have you looked into adding an oil pressure gauge?

 

[NateDN10]

No. The oil pressure should go off if oil pressure drops below the minimum limit. Unless you have huge problems, this would only happen at hot idle (and probably not even then).

The only thing the light is really useful for is to tell you if your sump is empty!

 

[d00df00d]

Originally Posted By: 45ACP
I can respect that, but this site is ALWAYS talking about going thinner than the recommended oil weight by a vehicle manufacturer. (Please correct me if i am wrong.) Isnt that what Motor Oil 101 generally alludes?

Never confuse the content of that article with the general trend on this website.

 

[45ACP]

Originally Posted By: someguy
Have you looked into adding an oil pressure gauge?


I have.

Ive never put my imaginings into practice by bringing my vehicle to a speed shop, however. Perhaps next year i will.

Any ballpark figure and/or what all is involved to rig up a gauge, to the right of the steering column? (Sensor? Wiring? How does it get to a place where it can "know" the oil pressure, does it feed off the same sensor as the idiot light?) All these have kept me into going to a speed shop, where i can set myself up for them telling me it will cost ~$500 to put one in because i show up acting confident and with a hot car (i dont trust myself to work on my own car, previous owner hooked it up as it is i just left it like that.) Now, if it costs that much, fine, not a problem. But what all is involved? (Lady 'Stang runs well, but still. I want to know!)

(And d00df00d:

Im not sure i follow.. but that article IS this site.)

The funny thing is: It makes engines happy.. almost like they just got cosmetic surgery.

 

[someguy]

Find a good Mustang forum or general info site and they will certainly have a how to with pics on adding an oil pressure gauge. I don't know of any but here are the instructions for a Focus http://myfordfocus.com/how-to/oilgauge.htm same general concept

 

[FL_Rob]

Does he..do youhave a Mustang 45ACP ?
what engine are we talkin' about?

 

[45ACP]

Originally Posted By: FL_Rob
Does he..do youhave a Mustang 45ACP ?
what engine are we talkin' about?


Yeah man its the 5.0 'Stang that they say had a displacement of 4.949 not 5.0

I dont touch it, it runs good i just made the oil half 5W20 and half 5W30.

No gauge, AFAICT. 1989, if you must know.

EDIT: Maybe somehting like this would be alright. Looks expensive.

 

[d00df00d]

Originally Posted By: 45ACP
(And d00df00d:

Im not sure i follow.. but that article IS this site.)

Not from where I'm standing. Only a minority of people actively posting seem to agree with that article; most either disagree or don't take a position either way.

 

[river_rat]

Well, if the OP light never flickers at idle after a long, hot highway pull, that's a good sign at least.
You can also just go buy a mechanical guage and run it to where you can see it...temporary installation without drilling holes. Get an idea what you are running and then take it off. Not super hard.
It's much harder to do a neat, permanent installation while retaining the OP warning light function.
I had one tied to a windsheild wiper for a while so I could read it through the windshield because installation was a pain.

 

[Astro14]

Look, the idiot light is a "too late" warning...it only warns you if the pressure is way, way low, like 4 PSI...so it can only tell you when you're effectively at zero...if it flickers at a hot idle, then your oil is too thin.

If you can't tell your pressure, then stick with the factory recommended viscosity. An experiment in viscosity without a gauge will yield one of two results: complete success or engine damage...and you won't know which one for quite a while...

If you want to experiment, then you need to be able to measure the results. A good autometer electric gauge is about $50....and pretty easy to install (T it off the OP light sender...). Then, you can actually tell what's going on in your engine...aand you can see the results of your viscosity experiment...instead of experimenting while blindfolded...

 

[45ACP]

Originally Posted By: d00df00d
Originally Posted By: 45ACP
(And d00df00d:

Im not sure i follow.. but that article IS this site.)

Not from where I'm standing. Only a minority of people actively posting seem to agree with that article; most either disagree or don't take a position either way.


Im not necessarily disagreeing with you sir, but its one of the most vocal minorities i have ever heard. Those posters sing its praises on every thread they post on. It has got me intrigued enough to go lighter, and now im somewhere in the middle, i am honestly asking myself if i am doing my engine a long-term disservice as there could be days (or weeks) where the car is in motion on the highway (and off) for literally hours a day, long long cross-country trips are possible on my 5W20/5W30 blend. Thats the main reason i make this post.... that article really made me do some thinking, and i cant come to a solid "Yes i am 100% confortable with me going lighter on my oil" or "No i dismiss everything in that article." Its a strange uneasiness of have i given my engine an early death serntence, or have i done the best thing i could have done for my car. I cant call it.

Hence, this thread.

 

[urchin]

Actually on many cars today , probably most of them, here are TWO pressure senders, one located on or near the oil filter housing and another in the top of the head usually on the side of it.

They are actually pretty accurate and effective at keeping those that heed them from destroying an engine. When you see the light and hear a audible buzzer or chimes you need to stop NOW! If you heed the warning immediately and pull to the side of the road shutting the engine off you have saved your engine.

Slight flickers of the light means that you can continue to drive but the car needs to be looked at soon.

 

[FL_Rob]

If it were me...30wt maybe redline (ouch i know) .you got a roller cam thank, "you know who" for that ...xW30 would suffice.

The guys I knew that raced 5.0 engines('stangs) did say that they "loosen up" over a short racing time.