Oil levels:just how far over the F is too much?

[Red Zircon]

I tried looking in the archives for precise information. I'm unsure if
I should add to an old discussion or start a new one: this is one of
the few times I've participated in a group discussion. (Please let me
know if I have it wrong.)


Question:
We have bought a 2002 Miata, (called MX5 in Australia) and I am just a
little worried about what might be excess oil, damaging the engine.
(The last owner might have slightly overfilled the oil.)

The level on the dipstick reads above the full level, about 7-8mm above
the F line. The oil pressure gauge reads half way between the half-way
mark and the next mark (next mark is at one o'clock.)

Just exactly how far in millimetres (or parts of an inch) over the F
line will cause problems?: I was under the impression car engines had
an oil pressure relief valve to avoid engine damage. Perhaps not?

Otherwise we are well pleased with our purchase.

Silver MX5 /Miata

[Chuck]

The oil pressure indicator has two positions only. No pressure and pressure.

Overfilling can cause the oil to foam, as it can be whipped by the
crankshaft if overfilled too much.
Extreme overfilling will cause serious, easily noticeable internal damage.

Generally, one side of the dipstick reads higher than the other. On my 99,
~3-1/2 US qts.
with a filter change produces a full oil level, with one side below the
line, and one side above.
4 quarts total is safe in most cases.

As far as the oil level is concerned, drain the excess out. Remove, drain,
and reinstall the old filter as many times as necessary to bring the oil
level to normal if you do not want to remove the drain plug. Either method
is messy. Pour the excess oil into a clean jar to measure the quantity.Then
when the level is correct, operate the engine over its rpm range while
driving. If no excess engine vibration is encountered, it's very unlikely
that engine damage occurred.

Post by Red Zircon
I tried looking in the archives for precise information. I'm unsure if
I should add to an old discussion or start a new one: this is one of
the few times I've participated in a group discussion. (Please let me
know if I have it wrong.)
We have bought a 2002 Miata, (called MX5 in Australia) and I am just a
little worried about what might be excess oil, damaging the engine.
(The last owner might have slightly overfilled the oil.)
The level on the dipstick reads above the full level, about 7-8mm above
the F line. The oil pressure gauge reads half way between the half-way
mark and the next mark (next mark is at one o'clock.)
Just exactly how far in millimetres (or parts of an inch) over the F
line will cause problems?: I was under the impression car engines had
an oil pressure relief valve to avoid engine damage. Perhaps not?
Otherwise we are well pleased with our purchase.
Silver MX5 /Miata

[Mal Osborne]

8mm I would not worry about. You may get a little leakage if the sump
gasket or some other seal is on the way out, but probably nothing bad will
happen.

Post by Red Zircon
I tried looking in the archives for precise information. I'm unsure if
I should add to an old discussion or start a new one: this is one of
the few times I've participated in a group discussion. (Please let me
know if I have it wrong.)
We have bought a 2002 Miata, (called MX5 in Australia) and I am just a
little worried about what might be excess oil, damaging the engine.
(The last owner might have slightly overfilled the oil.)
The level on the dipstick reads above the full level, about 7-8mm above
the F line. The oil pressure gauge reads half way between the half-way
mark and the next mark (next mark is at one o'clock.)
Just exactly how far in millimetres (or parts of an inch) over the F
line will cause problems?: I was under the impression car engines had
an oil pressure relief valve to avoid engine damage. Perhaps not?
Otherwise we are well pleased with our purchase.
Silver MX5 /Miata

[Red Zircon]

Thanks for the thoughtful replies. I will do some reading about the
mysterious dipstick, I recall seeing some other info here about the
levels being different on opposite sides.

Oil appears normal without froth, and underneath there is no sign of
leakage. I'll be keeping an eye on it. The car is going in for its
40,000 first major service soon: my chance to ask some more questions.

The Mityvac sounds like a fuss-free way to get the level down,
especially since there is so little room under the car. I'll also
investigate the oil pressure gauge, which, if it only has an on and an
off display, sounds like it's little more use than eye candy: my father
would have laughed himself silly if he saw this, as he liked to
meticulously measure just about everything.

[Chris D'Agnolo]

Your father was a good man ;-) Mazda has been lambasted for their odd
looking 'idiot light' actually it's worse, it doesn't light up bright red
when it's too late like an idiot light. Anyway, lots of people change it out
for a proper or near proper gauge / sending unit. You can find out lots more
about this and absolutely anything miata related at miata.net . Seems like
someone was getting a miata.com up and going too but the dot net site is
incredible for sure.

Chris
99BBB

Post by Red Zircon
Thanks for the thoughtful replies. I will do some reading about the
mysterious dipstick, I recall seeing some other info here about the
levels being different on opposite sides.
Oil appears normal without froth, and underneath there is no sign of
leakage. I'll be keeping an eye on it. The car is going in for its
40,000 first major service soon: my chance to ask some more questions.
The Mityvac sounds like a fuss-free way to get the level down,
especially since there is so little room under the car. I'll also
investigate the oil pressure gauge, which, if it only has an on and an
off display, sounds like it's little more use than eye candy: my father
would have laughed himself silly if he saw this, as he liked to
meticulously measure just about everything.

[my_two_cent]

With regard to the dipstick issue. I have a 96 and it is my considered
opinion that the dipstick scrapes the sides of the tube on the way down
and often smears oil on one side of the stick, giving a false reading.

Read the lowest perpendicular demarcation between oil and no-oil. That
is where the sump level really is. The rest of the oil is on the stick
from scraping on the sides. Be very careful reading new oil. Move the
stick around until the sun glint tells you where the perpendicular
dividing line is located. If the side you are looking at is all smeared
with oil, turn the stick over and read that side. That side may also
have some oil on the edges, but you should be able to see the
demarcation line clearly. I forget, does the stick have holes? If the
hole is filled, the oil is above that mark. All dipsticks should have
at least two holes -- only way to accurately read a dipstick. I think
my Miata doesn't have holes but my MPV does.

[Remove This]

Why not put holes in the dipstick. Use the measurements Above/Below the fill
that you have on the MPV.
Can't hurt.
--
I work for the ILEC ...." stuff happens! "

Post by my_two_cent
With regard to the dipstick issue. I have a 96 and it is my considered
opinion that the dipstick scrapes the sides of the tube on the way down
and often smears oil on one side of the stick, giving a false reading.
Read the lowest perpendicular demarcation between oil and no-oil. That
is where the sump level really is. The rest of the oil is on the stick
from scraping on the sides. Be very careful reading new oil. Move the
stick around until the sun glint tells you where the perpendicular
dividing line is located. If the side you are looking at is all smeared
with oil, turn the stick over and read that side. That side may also
have some oil on the edges, but you should be able to see the
demarcation line clearly. I forget, does the stick have holes? If the
hole is filled, the oil is above that mark. All dipsticks should have
at least two holes -- only way to accurately read a dipstick. I think
my Miata doesn't have holes but my MPV does.

[Red Zircon]

I think the idea of drilling holes is a great idea, as the dipstick is
hard (misleading?) to read depending on which side you're looking at.
Oil readings on each side usually vary form each other. Drill holes
would have to be kept small: the last thing I need is the bottom of the
dipstick breaking off while driving!

I also think the oil pressure gauge actually works. I've taken a few
photos and a short movie to prove to myself that the needle is really
showing different pressures. We'll see . . . perhaps it just my
boundless optimism created by this beautifully-balanced car. I'll take
or one two photos more, and if I'm convinced the gauge works I will
post the photos and movie.

[Mal Osborne]

My '94 Aussie spec MX5 has a proper analog oil gauge, maybe it was just
certain years, or certain countries, or certain years in certain countries
that had the crap one.

Post by Red Zircon
I think the idea of drilling holes is a great idea, as the dipstick is
hard (misleading?) to read depending on which side you're looking at.
Oil readings on each side usually vary form each other. Drill holes
would have to be kept small: the last thing I need is the bottom of the
dipstick breaking off while driving!
I also think the oil pressure gauge actually works. I've taken a few
photos and a short movie to prove to myself that the needle is really
showing different pressures. We'll see . . . perhaps it just my
boundless optimism created by this beautifully-balanced car. I'll take
or one two photos more, and if I'm convinced the gauge works I will
post the photos and movie.

[Leon van Dommelen]

Post by Mal Osborne
My '94 Aussie spec MX5 has a proper analog oil gauge, maybe it was just
certain years, or certain countries, or certain years in certain countries
that had the crap one.

They started the idiot gauge in 95 and kept it until 2006.

Leon

Post by Mal Osborne

Post by Red Zircon
I think the idea of drilling holes is a great idea, as the dipstick is
hard (misleading?) to read depending on which side you're looking at.
Oil readings on each side usually vary form each other. Drill holes
would have to be kept small: the last thing I need is the bottom of the
dipstick breaking off while driving!
I also think the oil pressure gauge actually works. I've taken a few
photos and a short movie to prove to myself that the needle is really
showing different pressures. We'll see . . . perhaps it just my
boundless optimism created by this beautifully-balanced car. I'll take
or one two photos more, and if I'm convinced the gauge works I will
post the photos and movie.

[Leon van Dommelen]

Post by Leon van Dommelen

Post by Mal Osborne
My '94 Aussie spec MX5 has a proper analog oil gauge, maybe it was just
certain years, or certain countries, or certain years in certain countries
that had the crap one.

They started the idiot gauge in 95 and kept it until 2006.

Until 2005.

Post by Leon van Dommelen
Leon

Post by Mal Osborne

Post by Red Zircon
I think the idea of drilling holes is a great idea, as the dipstick is
hard (misleading?) to read depending on which side you're looking at.
Oil readings on each side usually vary form each other. Drill holes
would have to be kept small: the last thing I need is the bottom of the
dipstick breaking off while driving!
I also think the oil pressure gauge actually works. I've taken a few
photos and a short movie to prove to myself that the needle is really
showing different pressures. We'll see . . . perhaps it just my
boundless optimism created by this beautifully-balanced car. I'll take
or one two photos more, and if I'm convinced the gauge works I will
post the photos and movie.

[Natman]

On 14 Apr 2006 00:46:14 -0700, "Red Zircon"

Post by Red Zircon
I tried looking in the archives for precise information. I'm unsure if
I should add to an old discussion or start a new one: this is one of
the few times I've participated in a group discussion. (Please let me
know if I have it wrong.)
We have bought a 2002 Miata, (called MX5 in Australia) and I am just a
little worried about what might be excess oil, damaging the engine.
(The last owner might have slightly overfilled the oil.)
The level on the dipstick reads above the full level, about 7-8mm above
the F line. The oil pressure gauge reads half way between the half-way
mark and the next mark (next mark is at one o'clock.)
Just exactly how far in millimetres (or parts of an inch) over the F
line will cause problems?: I was under the impression car engines had
an oil pressure relief valve to avoid engine damage. Perhaps not?
Otherwise we are well pleased with our purchase.
Silver MX5 /Miata

I had the same problem. The US owner's manual specifies 4 US Quarts.
Actual capacity is 3 1/2 Qts.

No need to drain the oil. I used the Mityvac that I usually use to
bleed brakes to suck the extra oil out of the dipstick tube.

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