Overfilling by 0.5 qt - ‘17 Miata

[Ride_Red]

I drained my RAV4 on ramps on a sloped driveway and it drained more oil out of the engine. Manual says either 4.5 or 4.8qt for oil & filter change. I put the whole 5qt jug in and it came up to the full mark.

Try ramps and/or let it drain a little longer. You'll most likely find that putting in the full 5qts with be at or just slightly above the full mark on the dipstick. If it looks too full for you, you could always loosen the oil filter and drain that half quart back out. OR, just pour in the 4.5qt, back it off the ramps and then add until full.

You never know unless you try.

 

[MetalSlug]

Every oil change place or dealers always overfill

 

[JoelB]

I've pondered this for our Accents. They call for 3.8 qts. The first oil change I poured in 4 quarts and it was slightly over the full mark. Probably no issue but I'm paranoid so I pour in the 3.8 quarts now. Unlikely it would ever cause an issue though.

 

[ARCOgraphite]

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.

Understood. But is the sump sized to be full in operation? 7x7x6" would be 5qts, then subtract volume of pickup and and irregular intrusive shaping. So that 4.5 qt keeps you from flooding the near windage area. Static.

A running engine and static level are two different conditions or states. At some point (typically not known) you will flood the upper side of the windage tray and you will get foaming. May happen on a fast onramp or at a uphill or down hill light. Or just sitting at idle.

I will reiterate, most every owner's manual cautions about overfilling, some even state (the) 'excess oil should be removed immediately or engine damage may occur which is not covered by warranty'.

Where this overfill cut point is varies. I would use ~1 cup or 250ml max - a typical margin of fill error.

Another thought, think modern light grade oils are a bit of saving grace here vs. a not warmed 20W50 or 10W40.

I could give sage advice here, but I prefer in this subject to give what should be considered professional advice.

 

[ThatNavyGuy]

Just saw this relevant video. Not scientific but more for entertainment value.

 

[burbguy82]

Hard to say. If the crank dips into the sump and creates void, that is a big problem. As I understand it, it is better to be a little low, than too high.

 

[IndyIan]

Just saw this relevant video. Not scientific but more for entertainment value.

Interesting though, to see what happens at the extreme. I have to admit I just give the Outback the whole 5.2 quart jug, and even the Focus seems to take 5.2 quarts instead of 4.5 and just goes over the full mark.
The Focus will just get down to low mark in 9-10k miles when filled this way so I call it good.

 

[FTTSHO]

The oil level in the oil pan will go down quite a bit (about half way down the low and full mark of the dipstick) when the engine is running compared to when the engine is off.

A lot of the oil on the sump will actually be pumped up by the oil pump, and will be circulating in the oiling system, so the oil pan level will drop with the engine running.

When you are high up in the rpm range, the oil level will go down drastically, which isn’t ideal especially if you’re driving around tight corners, so adding a little bit extra oil won’t hurt.

An extra half a quart will not harm anything. I would just add the extra half a quart and be done with it.

My old 4.3 Vortec GM engine also takes about 4.5 quarts according to the owners manual, but I just put in 5 quarts. Never had any issues, and the oil level on the dipstick is in between Full and low while the engine is idling.

Also, my 2010 ford Taurus SHO with the 3.5 Ecoboost engine supposedly was fine with 5.5 quarts back in 2010 when I bought it, but the dealer put in a new “latest TSB” dipstick couple years ago, and they said 6.5 quarts of 5w20 is the “latest” spec for my engine. So technically, my car can run on 5.5 quarts, but it also can run with 6.5 quarts as well, even with the same oil pan and filter. They changed it because of fuel dilution issues thinning the oil out too much in between oil changes.

Just an interesting thing I wanted to share!

 

[Gasbuggy]

I overfill just about everything I change oil on. Just like FTTSHO here, started almost 20 years ago with my 99 Ford SVT Cobra when it was decided 7 quarts instead of 6 was preventing oil starvation bearing failures. Anything taking 4.whatever gets 5. The CTS-V calls for 6, gets 6.75

I've converted several people I know to rounding up on their refills. It's nice to not have to add makeup oil if you're doing a sample. Gives a nice cushion when it's a car that doesn't get the oil checked by anyone.

 

[garageman402]

Remember the oil will expand about 10% when at operating temperature, so if it makes you feel better, put the 4.5 qts in, run it, then check it first thing in the morning, it should be about .45 qt lower than when it was hot. Lake Speed Jr. did a foaming test at the HPL lab, & when the oil was heated, it expanded from 180ml to almost 200ml, about 10%. I've always checked the oil level first thing before starting because all the oil has drained back into the pan, but I never considered heat expansion.

If there is an oversize oil filter available, consider using it to take up a little more of your leftover.

 

[CarlB]

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?

Probably better luck on the Miata forum. Anecdotes from folks with totally different engines won't be able to answer.

My guys have never overfilled a Miata to find out.

 

[malibuguy79]

Use the extra .5 quart to run out the old oil out of the pan after draining before you do up the drain plug.

 

[SHOZ]

I'd say better a 1/2 quart over than under. Unless you are like my Gen Coupe that has fuel dilution so bad +1/2 quart is the usual situation when it's time to change.

 

[Urshurak776]

So, in summary of the 3 pages so far.

OP: don’t do it, do it (not a problem) and it depends.

I love it here!

 

[SiRDOHC]

Since this thread was re opened. OP i would try what Ride Red suggested. Also maybe put the larger RX8 oil filter on if there is clearance and maybe it will be only a very slight overfill (100ml?) which is insignificant compared to half a quart extra.

 

[gfh77665]

Half a quart of oil spread out over the area of the oil pan is a minuscule amount.

If only more people understood that concept there would be far, far less concern of any small overfill.

 

[garageman402]

If only more people understood that concept there would be far, far less concern of any small overfill.

I'm not so sure about that, the manufacturer puts those values on the dipstick for a reason. Granted, they may have left margin for error, but I wouldn't test that. Maybe they were counting for expansion when hot so left some space. Without actually disassembling & measuring oil height, crankshaft location, etc. we're just shooting in the dark. As important the issue of aeration is, I'd stick to the full mark, nothing more. A safer way to put that extra oil to use would be to find an oversize oil filter as mentioned above

 

[SHOZ]

More than likely the manufacturer has a built in safety for overfill as most people are ignorant.

 

[SHOZ]

 

[himemsys]

Yeah, I thought about posting that video here. It's certainly opened my eyes a bit on slight overfills.