Overfill of oil.. What happens?

[Seth]

What damage is caused by overfilling the engine oil? and How? Reason I ask is that I am suspicious that my dipstick is not reading right..

Dont manufacturers take this into consideration when designing engines?

 

[Patman]

I'm sure most engines can easily tolerate a half quart more than the capacity listed in the owner's manual, in some cases even more. In the case of my Corvette, GM actually recommends overfilling the crankcase by one quart if you're going to do any racing. So I overfill mine and leave it that way always.

 

[Seth]

I checked the dipstick because I was hearing a minor ticking/tapping noise from engine. Is this the dreaded valve train chatter? Or is this normal cause of the low temps?

 

[CBDFrontier06]

On new engines that are still 'tight' regarding piston rings, you shouldn't even notice a difference with +1/2 a quart. Much more than that and foaming can occurs, depending on your pan design. This is rarely a good thing.

Older engines that are suffering a loss of ring sealing can get excessive amounts of oil entering the combustion chamber, causing problems like spark plug fouling and detrimental effects on the emissions systems. Oil isn't great for catalytic converters.

Some folks believe that the more oil you have in the crankcase, the more pressure you'll have. This is false. Oil pumps perform at the same pressure and volume (depending on oil viscosity, of course) whether you've got 3 quarts or 6 quarts in the pan. The only thing that changes pressure is low oil, when air enters the pump..and that change is to the negative.

The only real upsides to overfilling an engine is slightly more cooling and less chance of air entering the pump during hard cornering, which is why Patman's Vette would benefit. Depending on what engine you have, there can be a fine line between it being advantageous and just having an engine full of foamed oil.

 

[Patman]

One more upside to overfilling an engine is that it reduces the overall stress on the oil.

If you've got an engine which calls for 4 quarts for instance, and you find out you can safely run 5 quarts, then in theory your oil should be in the same shape at 5000 miles with 5 quarts as it would've been at 4000 miles with 4 quarts. So the TBN of your oil will benefit as well.

 

[RedDart]

Like many things in life, too much oil may not be a good thing. If you go too far beyond the manufacturers capacity recommendation you run the risk of parisitic power loss because the crankshaft counterweights will have to spin through oil during operation (also causing foaming). A windage tray may be able to mitigate against this situation to some extent.

 

[CBDFrontier06]

This kinda reminds me of the recall GM did on the early 2.5 liter (Iron Duke) Pontiac Fiero. Apparently owners kept running the cars out of oil during the warranty period, so instead of designing and installing a higher capacity oilpan, they redesigned the dipstick to require 5 quarts of oil to read "full" instead of 4. The genius of GM.

 

[Lonnie]

Dealerships have tested the theory that close is good enough. Overfull costs them money and too low means that #@$%! red light won't go out, so from a quart low to a quart overfull is okay if it's not your car. For me, right on the line is where it stays.

 

[CBDFrontier06]

Amen, brother.

 

[Greggy_D]

My Taurus calls for 5.5 qts. I just round up to 6 and call it a day. No bubbles have been observed on the dipstick after a run. I'm with Patman's line of thinking.....more oil (safely) means the TBN stays higher longer.

 

[robl]

Interesting, so my vehicle, which I have seen call for 4.5, 4.6 qts of oil. I buy the big 'jug' of 5 qts and pour 4.5-4.6 into the pan and watch as I pour and make sure I am close. I could safely just dump in the whole 5 qt jug with no issues? Then I wouldn't have to sit and judge 4.6 qts? And of course I check the dipstick, and it is pretty much at the full line. I'd be nice to just dump in the full jug, nice and easy!

 

[Patman]

Quote:

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Interesting, so my vehicle, which I have seen call for 4.5, 4.6 qts of oil. I buy the big 'jug' of 5 qts and pour 4.5-4.6 into the pan and watch as I pour and make sure I am close. I could safely just dump in the whole 5 qt jug with no issues? Then I wouldn't have to sit and judge 4.6 qts? And of course I check the dipstick, and it is pretty much at the full line. I'd be nice to just dump in the full jug, nice and easy!

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I think you could probably safely dump in the full 5 quarts. In fact I do that with my wife's Honda, her manual calls for 3.6L, but I've been just keeping it simple and pouring in an even 4L for years now, with no problems. I just wish that they didn't start selling most oil up here in 4.4L jugs now! That's probably a little bit too much.

 

[CBDFrontier06]

I have rounded up with all my vehicles if they take X.5 quarts. My 86 Civic did burn it down to "full" by the time 3000 miles rolled around, but it seemed to stop burning at that point.

 

[rpn453]

Quote:

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I checked the dipstick because I was hearing a minor ticking/tapping noise from engine. Is this the dreaded valve train chatter? Or is this normal cause of the low temps?

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What engine? A lot of OHC solid-lifter designs always tick a little.

 

[PT1]

You should not overfill. Park your car on a level surface and let it sit overnight. Then check the oil the next morning. That will be your most accurate reading. Overfilling can lead to oil aeration which is not good. If you have valvetrain noise switch brands until you find one that your engine "likes". This is assuming your don't have a mechanical issue.

 

[Merkava_4]

I've got a little Buick that says to put 4.5 quarts of 10W-30 in the engine from owner's manual. I decided from day one that I was going to put the whole 5 quarts in. The interesting thing is, after running the oil through the filter, the dipstick reads right smack on the full line and not over.

 

[steveh]

Could you minor tick just be fuel injector noise??

 

[Seth]

Quote:

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What engine? A lot of OHC solid-lifter designs always tick a little.

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A brand new SOHC engine. It has 1300 km on it. I drained the factory fill at 1000 km and am noticing the engine is slightly louder now. Especially the tapping noise.

 

[Seth]

Quote:

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You should not overfill. Park your car on a level surface and let it sit overnight. Then check the oil the next morning. That will be your most accurate reading. Overfilling can lead to oil aeration which is not good. If you have valvetrain noise switch brands until you find one that your engine "likes". This is assuming your don't have a mechanical issue.

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I didnt do the oil change. Dealer did. Perhaps you are right.. my engine does not like this oil

and no hopefully there is no mechanical issue since this is a brand new car.

 

[JustinH]

I'm very particular about getting the amount of oil right.

4.5 quarts for the girlfriends neon, with a new filter.

Thats exactly what goes into it.

And the next time, I only have to buy 4 quarts for her oil change, not the 5 quart jug.