Oil Capacity - This is Strange?

[ShadowsPapa]

I think FCA 5qt is on the safe side. Considered some drains while the oil is hot vs cold and some even let it drains over night as well.

Yes

I blew a head gasket on mine first car from overfilled, been filling to between the low and high marks since lol.

Coincidence.

When there's too much oil what happens is the wind in the crankcase whips the oil into foam sort of like strong wind does to a big lake or ocean.
'Foamy oil' can be "compressed" due to the air in it, and means you now have trouble with oil pressure being low, and the air in the oil is not good for bearings and lifters, etc.
Many engines have "windage trays" in them to help isolate the wind from the spinning crankshaft from the surface of the oil. Some engines you can easily get by with a whole quart "over full", others are at risk with that much too much. Engines with windage trays are not as susceptible to the damage from the crankshaft whipping the oil into a nice chiffon.
Old school engines built for high RPM and high performance often have windage trays installed in them so they can be run with more oil and to help prevent the higher RPMs from whipping the oil.

Too much oil results in damage to bearings, low oil pressure, starvation for lubrication, issues with valve noise due to lifters not getting pure oil, etc. It's a lubrication and oil pressure issue. Normally you'd see the results on the oil pressure gauge, temperature gauge, or hear it in a noisy valve train. Imagine the impact on modern engines with VVT and VVL. OR say a Mercedes with variable intake manifold volume, etc.

My guess is that the modern 3.6 can deal with a little too much oil because it's a given many dealers, OWNERS and others, like Bubba's shade tree mechanic uncle have put 6 quarts of oil in hundreds of these things. I don't want to find out, though.

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[spectre6000]

So... I want to say people are overthinking this, but I'm afraid it's the opposite. There may be printed words in a manual stating a 5 qt capacity, but there's also printed words saying to fill it to the full line on the dipstick, and add a quart when it gets to the other line. If we accept that Jeep is building even halfassed engines, and not pulling dipsticks out of a spare parts bin by the shade tree, the length of the dipstick and the placement of those lines have a very specific purpose. The top line is where they want you to fill it. It's at the top of the narrow part of the oil pan, and below the windage tray. If you overfill a little (like, a full quart), the oil pan opens up at that level such that that quart will maybe get you to the top of the "pill". This is by design on nearly every modern engine to allow for people to goof up and not wreck anything. I say nearly, but I'm not aware of any where this is not the case; even the really high end performance stuff doesn't care these days due to dry sump remote oil reservoirs. There are a lot of idiots out there, and it doesn't take an advanced degree to be a grease monkey. There's a lot of forgiveness in the design of anything the user might touch. If you drain your oil, add 5 quarts, and you're between the lines, you're technically fine. If it gets to the bottom line, add a quart. If you add 5, and you're between the lines, and you want to fill it up (I certainly would), do so. That's the amount it's designed to accommodate, plus a little if you guess wrong on a partial bottle's worth. If nothing else, you should WANT the oil level as high as it can safely be so that when you're way up at an angle on a rock somewhere, you have less risk of leaving the pickup gasping air. Conversely, the whole argument falls apart the other way in that at that same angle, even if you're underfilled, you're likely to have some windage no matter how much oil is in there in addition to trying to lube your bearings with nitrogen.

Bottom line, the dipstick is the engineers telling you one thing. The printed material is a technical writer, or possibly marketer based on what's been cited, telling you something else. If it's my engine on the line, I'm trusting the engineer every time.

 

[Jonny A]

I am yet another, who fills exactly 5 quarts... then checks the dipstick, and adds as needed to full line. As in every machine, engine or gear boxes of all imaginable sizes. If there is a dipstick or some sort of bolt to pull to check fluid levels, I always use it and put my trust in that for indication of level. Obviously check at the recommended angle, weather it be level or at a indicated designed operating angle. I don't know if I ever witnessed any one fill a engine with oil and then not check the fluid level using the dipstick. That is just lazy and inept in my mind.

 

[Binfordtools]

Now, lets all have a beer and argue about something important like cigars or scotch.

The idea behind drinking scotch is NOT to argue about drinking scotch

 

[sharpsicle]

IF you pour in exactly 5 quarts of oil and you know you poured in exactly 5 quarts of oil, then there is no reason to, nor would it be prudent to, pour in additional oil. 5 qts. in, is 5 qts. in there, whether your vehicle is on uneven terrain or whatever...

Seems you don't understand how oil fills and dipsticks function. Also seems you don't understand the difference between "recommended" and real-world results. I would hate to have you performing a fluid change on my vehicles. If I add exactly 5 quarts as you state and the level on the dipstick is still low, then I need to add more. Doesn't matter what FCA says, the real world is what matters. Don't spread misinformation.

I hope all reading this thread understand that the 3.6 in any and all JT's or JL's, per FCA, takes exactly 5 quarts of oil.

I hope all reading this thread understand that fluid changes are, well, fluid, and will vary each time you perform the change. You must measure and verify the level after adding the recommended amount and adjust if necessary. There are always variables at play. So yeah, it's very possible you could have 5.2qts on an oil change.

 

[T Ray]

O.M.G. what if the five quarts don't have exactly five quarts in there? Maybe 4.9 or 5.1 now I'm really stressing ! Not

 

[ShadowsPapa]

O.M.G. what if the five quarts don't have exactly five quarts in there? Maybe 4.9 or 5.1 now I'm really stressing ! Not

Then you'll really have issues with bottled water. I've noticed that some have up to an ounce less than others. The Fleet Farm 1 gallon drinking water bottles will over-fill some other gallon bottles if I transfer to other bottles for easier storage.
And after I do an oil change I keep the oil containers and turn them up-side-down on the oil squirt cans I have here and after a couple of oil changes, I can almost fill one of them. So you THINK you are getting 5 quarts in your truck or car if you use quart bottles - hahaha, no - otherwise how could I keep my oilers full?

 

[T Ray]

Then you'll really have issues with bottled water. I've noticed that some have up to an ounce less than others. The Fleet Farm 1 gallon drinking water bottles will over-fill some other gallon bottles if I transfer to other bottles for easier storage.
And after I do an oil change I keep the oil containers and turn them up-side-down on the oil squirt cans I have here and after a couple of oil changes, I can almost fill one of them. So you THINK you are getting 5 quarts in your truck or car if you use quart bottles - hahaha, no - otherwise how could I keep my oilers full?

I think I'll just check my dipstick after starting the engine and letting it run for a bit, then let the oil settle for a couple of minutes and recheck and adjust accordingly.

 

[ShadowsPapa]

And yet........... (let others fill in the last 3 words)

So you are insisting your interpretation of a chart is absolute, there is no other way, everyone else is wrong. You are saying there is only right and wrong, nothing else, and you have nailed the former.
Capacity is absolute otherwise they'd give a range, correct?
Odd that when I fill a totally empty cooling system (an engine I have rebuilt and a brand new radiator) that their number is really close, but it's not exact. I can usually get more or less in the system than their number.
I can say the same for all of the automatic transmissions I have ever rebuilt, and to some extent air conditioners although those are usually very close - but you don't stop at their number if the pressures are wrong or the sight glass still has some bubbles, and when the pressures are good and the bubbles gone, you don't push more in because their number says "capacity xx ounces" or words to that effect.

Think of the thousands of Jeep owners you just saved from a life of stress and regret or from doing it wrong based on.............. interpretation.

 

[Jonny A]

The idea behind drinking scotch is NOT to argue about drinking scotch

I like to take a occasional walk with Johnny.

 

[Renegade]

My posts in this thread are being censored/deleted. No point in my posting any more here.

Will just repeat again, 5 qts. in is is 5 qts. in there. No reason to check a dipstick to ascertain that when you are doing an oil change.

Yes, you need to know your dipstick so to speak, as at times other then oil change day, you need to use/read the dipstick.

What if the oil containers were wrong, and didn’t really contain the amount advertised. You might have uncovered a conspiracy by the oil companies to make more money by selling less oil. I think we need to start measuring the oil from the jugs before pouring it in our Jeeps.
(I’m joking, you probably don’t actually need to do this...maybe)

 

[ShadowsPapa]

OK, that's it - I'm going to get one of these on order, Amazon...........

 

[Commodus]

On the 3.6L V6, how much oil goes in a 2021 JT? On my 2018 Rubicon JLU, I always used 5.7 quarts. I assumed that this was the same on my 2021 JT with the 3.6L V6 however, the owner's manual says "5-quarts" (picture below). I just changed the oil/filter and added 5-quarts of oil, then started it up. I let the oil settled back into the pan for about 10-minutes and checked it and it was 1/3 of the way on the safe indicator on the dipstick. So...seems like it needs more oil. Is the owners manual incorrect?

When I change my oil it always looks a little low on the dip stick, and always thought that strange. That is untill we took a road trip cross country and noticed that after driving a couple hundred miles the oil level does read full. No need to add more oil than manufacturer specifications

 

[WXman]

I started a thread on this topic back in September of 2018 over on the JL side and that thread was still going as of last month. It's funny how guys will take a simple topic and beat it absolutely to death. Two and a half years and they're still hashing it out. Lol.

The "PUG" (Pentastar Upgrade) engine was redesigned in some key areas. The oil pan was one of them. It does NOT require 6 quarts of oil any more.

This engine represents the first time in decades that a Jeep 6-cylinder does not require 6 quarts of oil, which is why most dealerships had no idea and some still don't. You need to remind them.

Also, after you refill the engine oil, and the new oil filter is installed, you should start the engine for <2 minutes and then shut it off and wait 5 minutes before checking the dipstick. Failure to do so will give you false readings.

 

[BamaJeepTruck]

I'm going to add a little bit of insight from my dealership service days. I was a tech for a couple years and a service advisor for a few more after that. What is billed on your work order is just that, nothing more. If the shop is using bottles and not overhead pumps then 5.1 quarts would be billed as 6 quarts. They don't keep half full bottles of oil in inventory. Imagine the nightmare and slick shelves that would cause along with the inevitable inventory variance issues. Anything from a new bottle is full billed for the quart. The remaining oil in the bottle likely makes its way into the techs box and next time they bill 6 again and use the oil from the first bottle on their next oil change in the shop. To be honest the unopened but billed bottles are probably the techs friend/family supply of free oil. If you have worked in a shop setting you also know they don't sit idle and wait for every last drop to come out like you may at home, and they sure as hell aren't waiting 10 minutes after the add oil for the level to stabilize. 99.999% of the time the tech did it correct, and that tech wasn't involved in what's written on your ticket. Parts department added the lines for the supplies needed and the advisor did the rest. If parts billed 9 quarts by mistake that doesn't mean the tech put it in, same if they billed 4. All that said, check your dipstick, and you'll catch that .001% mistake. I would always pop the hood and check the level with the customer during delivery back to the customer not only to show the customer it was right and nice clear oil, but also to cover my techs back and avoid comebacks if we could catch a mistake before it went down the road, but customer service is a dying art. Moral of the story, in Raegan's immoral words "trust, but verify" and the words on the paper are the official record, but that doesn't mean that's what happened. If the exact level on the stick matters to you then tell your advisor, or expect filled to the top line in my experience.

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