Overfilling by 0.5 qt - ‘17 Miata

[Redhawk454]

On a big displacement v8 half a quart wound do anything bad but on a little 4 banger I wouldn’t overfill it by that much

 

[edyvw]

On track filling more than required is normal thing. And there are A LOT of Miata’s on track. However, if you don’t track, keep it at 4.5qt.

 

[demarpaint]

I over filled by 1/2 a qt. for decades in a Ford Aerostar and a Buick Century. Both lived very long lives and were junked because the NY roads ultimately took their toll on them.

 

[Triple_Se7en]

My Miata takes 4.5qts, but I started wondering recently if any harm would come to the engine if I just dumped in a full 5qt jug. Being left with 0.5 qts after every oil change annoys me.

Thoughts?

No harm doing five quarts, unless over the course of the OCI significant fuel dilution occurs.
I wouldn't want 5-1/2 quarts where 4-1/2 quarts is the policy in your Owners Manual - not for the total length of your OCI. Would 5-1/2 be harmful for a thousand miles or so? I doubt it, unless red-line occurs constantly.

 

[JohnnyJohnson]

My Miata takes 4.5qts, but I started wondering recently if any harm would come to the engine if I just dumped in a full 5qt jug. Being left with 0.5 qts after every oil change annoys me.

Thoughts?

When I had a car that took 4 quarts that became Lawn mover oil.

 

[Malo83]

I have two vehicles that require 4.5 qts of oil, I just dump the 5 qts in with no problems.

 

[nicholas]

My Miata takes 4.5qts, but I started wondering recently if any harm would come to the engine if I just dumped in a full 5qt jug. Being left with 0.5 qts after every oil change annoys me.

Thoughts?

That's fine

 

[AZjeff]

If the pan sump "deep end" area is say 7x7 that would raise the level over a 1/2" which can be significant.

It doesn’t work like this. Think about it

 

[Cheetah-kins]

I have a '90 Miata and overfill by about a half quart myself. Haven't had any issues and in fact I think the motor runs quieter, too.

 

[Rogueman2016s]

wont hurt one bit been doing this for years. especially if you have a fuel diluting engine.

 

[chris719]

Most likely fine but you really don’t know, every design is different.

 

[Hermann]

I put a full 6qt instead of 5.7 in the Maverick, it doesn't even show overfull.

 

[Odd_Ball]

If the pan sump "deep end" area is say 7x7 that would raise the level over a 1/2" which can be significant.
One you hit the tipping point it can get nasty. Also the resonance of the crank case is calculated into the PCV operation and you change that frequency when you add fluid.

Once the deep end of the sump is full of oil (and it better be) it can have no bearing on the level rise due to additional oil added. It is the area of the top surface that determines how much the level will rise due to additional oil that is added.

 

[Patman]

wont hurt one bit been doing this for years. especially if you have a fuel diluting engine.

Think about what you’re saying here. If you have an engine that suffers from fuel dilution in the oil the last thing you’ll want to do is put in more oil and run the risk of the level being above the danger zone.

 

[GMBoy]

Remember the dipstick (we had a forum post about dipsticks awhile back) is just a rough gauge so that .5 qt may or may not be "overfilled". I checked the manual and capacity is 4.5qt w filter as you say and 5 qt dry engine so that shows a slight overfill condition can exist but it is nothing to worry about. I would be concerned about a full qt over but not 1/2.

 

[NormanBuntz]

Clean out an old 64 ounce juice bottle and keep it for your xw-20 leftover oil. It makes you feel good looking at nice oil through a clear bottle. Or even one of these:

 

[NormanBuntz]

I have two vehicles that require 4.5 qts of oil, I just dump the 5 qts in with no problems.

Not me. If it says 4.5, it gets 4.5.

 

[ThatNavyGuy]

Dump the full 5 quarts in my ND2 every time, no issues.
As was previously mentioned, due to the shape of the oil pan, you will get a better drain by putting the rear on taller jackstands. Probably not necessary but my OCD wants as much of the old oil out as possible.

 

[hpb]

If you took it to a workshop and they overfilled it, would you be happy? I wouldn't. Put in the correct amount and save the extra for top offs, or just use it at the next service...

 

[himemsys]

Think about what you’re saying here. If you have an engine that suffers from fuel dilution in the oil the last thing you’ll want to do is put in more oil and run the risk of the level being above the danger zone.

Yep. My CRV is a fuel diluter. Oil level climbs on the dipstick. I intentionally UNDERfill it slightly (3.5qts when it calls for 3.7qts) just to give a little buffer.