Pros and Cons of 5qts of oil at oil change instead of 4.5?

[Ray_73Turkis_OH]

I get the 5qt mobil 1 and just pour the whole thing in.

Oil pressure doesn't seem different.

What do you think?

[Guest Anonymous]

The capacity of the oil pan is what it is. You are not going to make it hold more than it is designed to hold by pouring more in. You can't keep 1/2 quart of oil in your trunk or behind one of the headlamps?

I'm sure there is a measure of forgiveness in that the actual amount of oil is not hypercritical and it probably is greater that 1/2 quart, - but why would push it? When you park or drive on an incline think about your margin of "safety."

Look on the bright side, by not being inconvenienced, you have increased the potential for blowing oil seals, and creating leaks that go from minor to major. Oh, then there is the windage factor. If you have the crank spinning in pooled oil, not only do you have to overcome increased drag/friction, you also tend to whip up or foam the oil. That, if you were not aware, is not a good thing unless you are making a pie topping.

Good luck.

[JohnW]

I don't see any benefits to overfilling. Overfilling can potentially damage the engine, although it's probably not too likely. And you're going to be making less power because the crankshaft is going to be trying to slosh around too much oil. I acutually underfill my cars a bit (just try to get about a quarter of the grid on the dip stick full). Never any problems and I've owned a lot of high mileage cars. Just keep a close eye on the oil level if you undefill slightly.

[TobyB]

the oil can get wrapped around the crankshaft in a frothy mess. Once it starts whipping, it gets fluffier as air is trapped, and gets more wrapped into the crank.

Other than lost hp,

the big problem is that you no longer have oil, you have foam. Foam is compressible, and not very lubricating. So oil pressure drops a little, and the bearings are getting air into them, which is bad.

On the track and race car, this will happen if I go over 1/2 way up the "OK" hash mark on the dipstick. So I run 'em a bit low, and the Accusump catches the pressure in the corners.

Frankly, if you want to cheat, put in 4 quarts and wait 'till you need more- THEN add that last quart.

fwiw,

t

[dubois]

I get the 5qt mobil 1 and just pour the whole thing in.

Oil pressure doesn't seem different.

What do you think?

Oil pressure is more directly related to the gaps and clearances that are present in the engine, where the oil is being forced thru by the pump as it forces volumes of oil (at least that's my understanding) . So how much oil you have in the reservoir, makes no effect.

[Lee]

I get the 5qt mobil 1 and just pour the whole thing in.

Oil pressure doesn't seem different.

What do you think?

Hi Ray. I would overfill only for track/race events to avoid any oil starvation, or air bubbles in your lubrication system in long or tight corners. For street use, there is no real use.

[Richard]

If you overfill the crank turns the oil to something like whipped egg whites. Even though your oil pressure is fine you do not get a complete film protection between METAL moving parts. As to overfilling for race or autocross that would compound your problem. Thats why racers put baffles in their oil pans.....

[Stacey]

I overfilled the crank case on my first car ('69 Beetle) when I was a kid, and caused it to spit gas out of the carb onto the alternator. We had a barbecue in the front driveway. Save tha 1/2 quart to top off at gas-up between oil changes.

Not recommended.

[jgerry2002]

5 quarts in a 2002 is fine.

Other cars like my E36 m3, you can go a full quart beyond the fill mark with no ill effects. It can help with noisy lifters, at least 2002s don't have that issue.

Some cars are VERY picky with oil fill levels though.

[TobyB]

a friend- who's a better driver than I-

was routinely putting in an extra 1/2 quart into her

E36 M3 LTW. And was having all sorts of lifter noise

after a good day's thrash at the track.

The short of it was that lowering the oil to 'right in the middle'

on the dipstick cured the lifter noise completely.

And oil pressure was better, too.

If you overfill a street '02 by 1/2 quart, it probably won't kill it.

If you then track it, it will die with 20 psi of air in the bearings.

It's your motor.

t