I dont' think it ever moves..it always is a few ticks above middle...

and it stays there even when the dipstick shows my oil level is below the recommended line :(

what could be wrong? :O

Its a dummy gauge there for the looks...will only move on extremes

There is nothing wrong. It is an oil pressure guage, not an oil level guage. You could be two quarts low and still maintain good oil pressure. Just check your level every 1500-2000 miles, thats about when I need to add a quart.

You should check your oil every 500 to 600 miles.

it's only a on or off gauge.

Gee, I check my oil every Friday. :) That's somewhere around 350-400 miles usually.

if it moves then its time to worry.

^Yeah, if so pull over immediately.

^... and for the love of god, check your oil level more frequently

There is nothing wrong. It is an oil pressure guage, not an oil level guage. You could be two quarts low and still maintain good oil pressure. Just check your level every 1500-2000 miles, thats about when I need to add a quart.


I'm pretty sure you missed the point on that remark..

Oil pressure is supposed to fluctuate. Out stock gauges are COMPLETELY WORTHLESS! At idle it should be about 30-40psi lower then WOT. Buuuttt, it never moves.

Actually... look at it (VERY) closely, it does move, just that it moves just short of a tick mark from idle to redline the rest of the needle's sweep range is unused. I wonder if there is a way to alter it to show a better representation of the oil pressure...

Idiot guages are kind of stupid, but in some ways they are smarter than we are. A person will gladly watch a guage slowly creep up as long as they think they can get to their destination before they think something "bad" will happen. People can easily fool themselves into thinking they are taking an acceptable risk when it seems inconvenient to do stop and do something. But if the guage suddenly shoots up, it will get a pretty immediate reaction, as it should.

no there is no way to alter it. in order to get an oil pressure reading you need to add your own sender and guage. the dash can module gets a signal from the pcm that indicates pressure or no pressure- on or off. thats it. there is no changing that.

Question answered. Thread closed. lol JKing.

It sucks compared to the oil pressure gauge in my FD--which frequently varies depending on gear and speed etc....

on my FC it varied GREATLY from idle to medium load. Weren't all mazda oil preasure gauges supposed to be equally useless?

Makes you wonder. Why have the guage at all if it's just on/off. That should be an idiot light. They ought to give us a guage for oil level; instead of making us check it with a barely readable dip stick every time we fill the thing with fuel (per owners manual).

Makes you wonder. Why have the guage at all if it's just on/off. That should be an idiot light. They ought to give us a guage for oil level; instead of making us check it with a barely readable dip stick every time we fill the thing with fuel (per owners manual).

They want to give the illusion of full instrumentation but don't want to have to deal with low oil pressure issues from the owners.

on my FC it varied GREATLY from idle to medium load. Weren't all mazda oil preasure gauges supposed to be equally useless?


Uh, how is that useless? If your gauge DIDN'T vary greatly from idle to load, you would know something was wrong. IE: a pinhole leak, low oil, etc...care to explain how you find that useless, hmm?

The RX-8 instrument clutter (not misspelled) was designed to look cool (rather than be functional) to hit the car's target demographic.

They want to give the illusion of full instrumentation but don't want to have to deal with low oil pressure issues from the owners.The RX-8 instrument clutter (not misspelled) was designed to look cool (rather than be functional) to hit the car's target demographic.Both correct. Ah, to live in a time when MBA's—rather than engineers—call the shots. :sad:

They want to give the illusion of full instrumentation but don't want to have to deal with low oil pressure issues from the owners.

yeah that's what the little oil light is for... which usually some tard comes here after driving home with it on and ask what does this light mean.. and then mugatu comes in and rapes them with a broken broom handle named search.

Ah, to live in a time when MBA's—rather than engineers—call the shots

It is even worst. Those MBA's were in many cases engineers, turned into bean-counters. And many drive Porsches.

Jose, aka "Hey Boss, pay me an MBA" :wallbash:

unless you have the oil temperature, pressure, engine rpm, and oil viscocity logged and continually calculating an oil pressure at the standard conditions for the rpm range and also the oil pressure chart to compare your numbers with across the rpm range - your real pressure guage isn't telling you anything a dummy guage isn't (you either got oil or don't)

disagree r0tor,
for instance it wasnt until i gauged my car did i see for myself that it would not hold the manuel's identified normal pressure at 3K with the recommended 5W20 oil. Need less to say i now run a 5w/30. oil pressure gauge can also identify(we dont have one with the 8) oil pressure drops during high G moves. oil pressure gauges are useful. like everything else they have a specific purpose and thats all. for some drivers the stock one would be fine. just cant believe mazda cheaped out on gauges.
olddragger

the oil pressure is HIGHLY dependant on the oil temperature and condition of the oil. 5-10 degrees or 10% changes in oil viscocity will throw off how much oil pressure you have by a substantial amount.

edit-> add the oil filter differential pressure to the list of things you need to measure to make sense of things

edit 2-> thinking about it, the ambient air temp will effect how much the oil cools down in the oil coolers which will effect the backpressure

od they didnt cheap out, they took the path of least resitance. they had huge complaints in the past about fluctuating oil pressures (they werent the only ones) because people dont understand how to read a normal oil guage. it is easier to deal with the fewer complaints from folks abotu the on/off variety we have than to deal with the other.

od they didnt cheap out, they took the path of least resitance. they had huge complaints in the past about fluctuating oil pressures (they werent the only ones) because people dont understand how to read a normal oil guage. it is easier to deal with the fewer complaints from folks abotu the on/off variety we have than to deal with the other.Yes, especially since many people were not even thinking oil pressure when they looked at the gauge - they thought their oil level is fluctuating. :dunce:

This is kind of a cop-out, Mazda advertises this car as a sports car. We all know it is a fine sports car and a sports car should have complete instrumentation. Oil pressure knowledge is something a sports car driver needs to know. I understand Joe Average may not know how to properly use a Oil Pressure gauge but that dose not mean you should delete it. Do you think Porsche use a idiot gauge?

correct me if im wrong but when your oil is running low youll get the oil light on the dash its red and annoying as hell

correct me if im wrong but when your oil is running low youll get the oil light on the dash its red and annoying as hell


When that happens.... its already pretty low. I think that light comes on after you're down about a quart of oil (completely pulled that out of my ass). However even when I'm topped off I swear i see that light out of the corner of my eye and when I look down... its not on! I hate that damn light.

thanks a lot guys :)

This is kind of a cop-out, Mazda advertises this car as a sports car. We all know it is a fine sports car and a sports car should have complete instrumentation. Oil pressure knowledge is something a sports car driver needs to know. I understand Joe Average may not know how to properly use a Oil Pressure gauge but that dose not mean you should delete it. Do you think Porsche use a idiot gauge?

Please tell me your knowledge of how to properly use an oil pressure guage...


Oil pressure guages are measuring back pressure and not flow. You can have high pressure and no oil flow (think blockage, cold oil, sludged oil), high pressure and too much flow (more pressure = more resistance), low pressure and no flow (break in the line somewhere), and low pressure and or low no flow (pump is broken or oil too thin from heat or fuel dilution). A real pressure guage will fail you in 1 out of the 3 cases just cases above that will hurt you just like the dummy guage will. Then for the back pressure to mean absolutely anything, you have to correct the oil temp, viscocity, ect to a standard condition and plot it as a function of rpm - which nobody is doing with a real pressure guage. Ironically, most real aftermarket guages have a dummy light just like our own dummy light and nobody pays attention to the damn guage until the light goes off.

A useful guage would be an oil flowmeter since thats what we are actually worried about. That would be a differential pressure guage across an orifice that you would then compare on a graph against the system backpressure and the oil pumps pump curve. It too would have to be corrected though to standard conditions to make sense out of it - but it would actually tell you if you had flow.

Mazda advertises this car as a sports car. We all know it is a fine sports car and a sports car should have complete instrumentation.

I disagree with your assumption. Mazda advertises this car to a certain demographic who, unfortunately, wants a cool looking dash rather than a functional one.

My pleasure, the gauge is an excellent indicator of possible problems with in your engine. It can give you advance warning of a problem before it strands you. The gauge can tell you if maybe you should use a heaver oil. It will tell you if your oil starving the engine in a turn. It can indicate a flow problem to be looked into. It can allow you set a bench mark that can be monitored over the life of the engine. It is not perfect but far better then an idiot light/gauge.

Please tell me your knowledge of how to properly use an oil pressure guage...


Oil pressure guages are measuring back pressure and not flow. You can have high pressure and no oil flow (think blockage, cold oil, sludged oil), high pressure and too much flow (more pressure = more resistance), low pressure and no flow (break in the line somewhere), and low pressure and or low no flow (pump is broken or oil too thin from heat or fuel dilution). A real pressure guage will fail you in 1 out of the 3 cases just cases above that will hurt you just like the dummy guage will. Then for the back pressure to mean absolutely anything, you have to correct the oil temp, viscocity, ect to a standard condition and plot it as a function of rpm - which nobody is doing with a real pressure guage. Ironically, most real aftermarket guages have a dummy light just like our own dummy light and nobody pays attention to the damn guage until the light goes off.

A useful guage would be an oil flowmeter since thats what we are actually worried about. That would be a differential pressure guage across an orifice that you would then compare on a graph against the system backpressure and the oil pumps pump curve. It too would have to be corrected though to standard conditions to make sense out of it - but it would actually tell you if you had flow.

I disagree with your assumption. Mazda advertises this car to a certain demographic who, unfortunately, wants a cool looking dash rather than a functional one.

Is this a different demographic then the previous RX cars? I would say no, the 4 seats may sway that argument a bit but it seems most of us compared this car to 350Z, S2000, M3, STI, EOV ect...... a group of car that uses real instrumentation.

My pleasure, the gauge is an excellent indicator of possible problems with in your engine. It can give you advance warning of a problem before it strands you. The gauge can tell you if maybe you should use a heaver oil. It will tell you if your oil starving the engine in a turn. It can indicate a flow problem to be looked into. It can allow you set a bench mark that can be monitored over the life of the engine. It is not perfect but far better then an idiot light/gauge.

how can you you make any of those assumptions when a 10 degree difference in oil temperature can effect pressure by up to 10 psi?

I didn't mean that the gauge on my FC was useless. I just stated that I had no idea that the one that we have now is so much different from the one I had then. (I didn't know the FC, FD had real oil presure gauges) as opposed to the 8.

and yes I wish the 8 had my old presure gauge. It was verry reasurring to see that the oil presure fluctuated depending on engine load.

Is this a different demographic then the previous RX cars?

I am not commenting one way or the other whether the demographic is different from previous RX cars. I am saying that I believe that the current demographic is more influenced by "bling" than by functionality (at least where it shows) and that this is demonstrated by a number of marketing directed technical decisions about the RX-8. The instrument clutter is one of the more obvious ones.

IMHO, of course.

how can you you make any of those assumptions when a 10 degree difference in oil temperature can effect pressure by up to 10 psi?

A little information is better then no information. As I stated it is not a perfect solution by any means but you can develop a bench mark at the least which will allow you to spot deviations from the norm.

As for "msrecant" I can see your point.

A little information is better then no information. As I stated it is not a perfect solution by any means but you can develop a bench mark at the least which will allow you to spot deviations from the norm.

I agree with you on this, which is why I miss the RX-8 not having a real oil pressure guage. On my 1993 Miata I could not make an absolute statement about the oil pressure gauge's reading at any given instant in time. However, I quickly learned what was "normal" and could easily spot when the reading did not jive with the current condition of the car. The info was useful to me, even if it could not be used by someone driving my Miata for the very first time (excluding extreme readings).

yeah that's what the little oil light is for... which usually some tard comes here after driving home with it on and ask what does this light mean.. and then mugatu comes in and rapes them with a broken broom handle named search.

that was awesome. :ylsuper:

Zoom
Never thought of it that way. Makes sense. I guess a lot of people that are not really mechanically inclined did buy the car. Thanks for the fresh perspective. For the rest of us it is a little aggravating. I wish they would have , at least, offered the real gauges as an option. Still a great car and putting gauges in it increases bonding time.
Rot0r--the manuel says the oil pressure (not flow-- thats another ballgame)should be 50.8 at 3k with oil temp at 212F. My reading --repeated many times--showed a reading on MY car to be 48-49 at 3K with oil temp at 185,. 47-48 at 195F. I didnt think the pressure would go up any at 212F so I stopped. It was enough to convince me to change to a 5W/30. That placed the pressure in a nice range--just slightly above stock norms. Conclude what you may-I'm convinced.
Olddragger