Hello fellows,

All of you who is now hoping for a perfect answer... I´m sorry.
I´ll always start a discussion with some additional informations and the right question.

The question ist...
Which exact steps do We have to perform to read the dipstick right.

I have an example.
Working for Mercedes-Benz @ the engine Developement and dealing with the oil circuit I know:

to use the dipstick right, you have to heat up the car to 90°C Oil temp.
Then you have to stop the motor. wait for exactly 5 minutes...
and then you can read the dipstick right.


So... does anyone knows right how they defined the procedure for correct measure with the dipstick?

Greetings from germany

Woeep

 

wtf.....

 

wtf x 2

 

Lol

 

Same proceedure you use on your benz will work on the 7..

Just get the vehicle up to operating temp, shut down the engine and give it a minute or two to allow the oil to settle. Then check the dipstick.

Don't over-engineer the oil check

 

The RX7 is much simpler than the newer Benzes. Just open the hood and check. I don't see a difference checking when hot or cold.

 

I can´t understand this reaction...
The oil check with the dipstick is so or so more an estimation then a real measurement.

But OK... seems like I can´t get the right information here.

"wait one minute or two to allow the oil to settle..."
I´m sorry, but I don´t exacly know how fast the oil will settle in the 13B.
Do you know?
And do you know how much difference in oil-amount can be between one or two minutes?
It can be a lot. But it is different from engine to engine.. Thats why I started the thread and asked!

f.e. in some Merc - engines the oil needs houres to settle.
And 10°C Temp difference can cause a dramatic amount difference, too.

10°C Temp plus "one or two minutes" wrong and 500ml of oil are where you heavent expected them. (IN the sump or not) And so you´ll have measured or better said estimated 500ml more or less, than your engine has in reality. And as Mazda engineers have meant to be there.

Just my 0.02$ no contention

Seems like i have to measure in and check this for myself

I´ll tell you after my next Oil change!!



EDIT:
"I don't see a difference checking when hot or cold."

--> Ever heared of oil viscosity?

To make it short:
When the oil is cold, it is not as fast flowing back to the sump as warm oil.
An example (no measured values... just to show!)
So if you measure 3 minutes after stoppinbg the engine with 40°C warm oil. Maybe only one litre has made his way back from the engine to the oil sump.
If you wait 3 minutes with 90 or 100°C warm oil, 2 liters have made their way back to the oil sump.
So when you measure...
Maybe with 40° warm oil you think you need to put some more oil into the engine while with 100°C warm oil everything seems to be OK.

 

which mercedes car needs hours for oil to settle?
then again, i always thought mercedes had poor engineering
oh and as long as ur stick dont read low, u'll be fine, its just a simple oil check, not rocket science
just my 0.02

 

big 12Zyl engines need houres !

Having a lot of innovations and having one of the best quality in engines at the moment (look at JD Power or other studies) are showing the opposite of bad engineering.

And as I said before...
Wrong time and wrong oil temp and you´ll read perfect oil amount even if it is low in reality...

poor engineering or not... this fact is understood by the poorest engineer!!

 

then you should have stuck with mercedes

 

No no ... The Rex is the right one (You know it too )
The difference is ... I´ll not stuck with Mercedes... I want to do it properly!

Trying to make it ok isn´t good enough for me!

 

Yes I have heard of oil viscosity. If you're so smart, why don't you go and do some testing with different time gaps for oil drainage back to the pan and different starting oil temps and educate us with your results.

My results have not shown a difference measurable by the naked eye with a warm engine or cold.

Good luck!

 

If the car is already cold, there is no need to start it, let it warm up, and then shut it down just to check the oil. All the oil that is going to go back into the pan is already there in this case.

If the engine is hot from driving, I generally wait about 30-60 minutes before checking the oil (unless I'm at the track as sometimes I don't have that much time between sessions).

 

Just check it cold, or wait a minute or two after it's been driven.

There's no point in being too ****-retentive about it... the car isn't going to be sensitive to fluctuations as small as would occur with viscosity changes due to heat. Guys routinely run the car a half to a full quart low on track to prevent excessive amounts of oil being barfed out of the oil filler neck with no ill affects, so the difference in 1/8 to 1/10 of a quart isn't going to matter.

There are plenty of perfectly reasonable things to obsess over with these cars, no need to add one :-)

 

it's going to burn the **** anyway, just put the dipstick in and pull it out, hot or cold, it doesn't matter that much. Add a little. If it's not exactly at the top, don't worry about it.

it's not like on a Mercedes where the oil is changed every 6-10k with synthetic and you want to be 100% sure that it is correct because the customer is never going to pop the hood.

 

In a related story: http://jalopnik.com/cars/all-your-ca...ief-265670.php

 

lmao obession with oil level even tho there are 100s of better things to worry about

 

OK... I think we can close this thread here

The answer is (so do I think):

It doesen´t matter...
On the RX7 engine it makes no big difference how and when you are measuring it.

So this isn´t really the answer I waited for... but it is one.

The question just came into my mind..
I´ve changed and checked the oil so often but I had never thought about how I should correctly (freaking correctly ^^ ) do it.

I´ll say it again:
The Answer is.
No matter how..., BUT DO!

 

Doesn't the owner's manual say something about waiting 5 minutes after shutting the engine down?

 

For some reason I have an overwhelming urge to paraphrase 'the Holy Hand Grenade' part of Monty Python's 'Holy Grail':

"Thou shalt taketh and graspeth the dip stick and thou shalt pull with seven pounds of force. Not six, not eight but seven. Seven is the number. And thou shalt lifteth the dipstick in one movement out of its holder. Yea verily ye shalt then observe the point that the oil covers and taketh note of this, and it is Good if the oil is above the lowest mark, but below the highest mark...."

http://www.youtube.com/watch?v=xOrgLj9lOwk

God I love that skit!

 

That is friggin hilarious. I'd like to see a BMW tech say that to a customer with a straight face.

 

BMW over engineers yet again. Thats just hilarious how they would check the oil.

 

pull the dipstick out hold it upside down for 30 seconds twist it about two revolutions then that should be good.

 

Your procedure is right, heat up the oil (run the engine) to reduce viscosity first, then wait a few minutes to allow almost complete draining .

But you should also be aware that if you drive your car hard, you should never overfill when you change oil and preferably do not fill beyond the minimum level indicated on the dipstick.

Under hard cornering, oil level tends to climb up to the oil filling neck and could get sucked by the turbos through the blowby gas hose (small rubber hose connected to the oil filler neck), then foul the IC. Make sure you never overfill when you change oil. If you drive your card hard, you should also consider installing a catch can to definitely prevent this from happening. For more info, see http://www.fd3s.net/oil.html under "Oil Catch Can"

- Sandro

 

Do the Mercedes engineers do a taste test too?

I generally check it every day it's driven. This time of year I usually park it in the garage with the hood up, so it's all of 30 seconds to check. Top of the hash-marks and I'm golden. End of story. Personally I don't think this belongs in the FAQs, because it isn't.