Too Much oil bad for engine?

Messages
135
Location
MD
If a car should be getting 3.5 quarts of oil and was getting 4-4.5 quarts, can this damage the car in any way? Can it: 1.) Clog the pistons and the rings? 2.) Damage the Catalytic Converter? 3.) Stress oil Seals? 4.) Cause foaming in the crankcase? Would it be bad or just make the car more sluggish because it has to work a little harder moving the oil around?
 
Messages
2,703
Location
Lincoln, NE
Unless you grossly overfill the crankcase, #4 is probably the worse that's going to happen. Foaming is not good though. You don't want your crank turning your oil into whip cream. Also, if you have too much oil, your sump may never reach a good operating tempature. This probably wouldn't apply unless you're doing 50%+ overfill.
 
Messages
1,407
Location
Vail, Colorado
Too much oil might put more pressure on seals. And, I'm pretty sure that the extra oil will end up making breather systems kinda messy! And if the oil foamed then it could be more serious. I'd bring the oil level down to normal, or no more than 1/4 of a quart over the full mark. If the oil filter is easy to get to, that might be one way to drain the extra!
 

Patman

Staff member
Messages
22,017
Location
Guelph, Ontario
It depends on the design of the oil pan. In the case of the LS1 f-body and Corvette, you can safely go 1.0-1.5 quarts over and you'll still have more than enough margin of safety that nothing bad will happen.
 
Messages
1,048
Location
Daytona Beach
You dont say how old the engine is. A modern design engine that runs the top ring way up near the deck of the piston can be pretty sensitive to excess oil. Even the normal way an engine gets rid of excess oil....by burning it off, usually by the PCV valve can stick a piston ring pack. This is especially true of older, pre - SL oils...they have more VI's which are the real culprit when it comes to sticking rings. If it was a Saturn, for example, the answer would probably be YES. If it was a Nissan truck, probably NO. Only the NEON engine has the crank running in an oil bath these days...foaming shouldn't be a problem with other engines.
 
Messages
450
Location
The Bay Area
you can blow seals as well as burn oil. depends on how much oil you add above full. to make it short, just stick with the manufacturer's recommendation, unless you've added an aftermarket part that requires more oil.
 
Messages
8,711
Location
Nothern USA
It has been discussed before, but is there any new thinking on the owner's manual vs the dip stick? Adding the 5.8 quarts the manual calls for, to my 02 Ecotec leaves the oil level above the full mark. It came from the factory with the oil above the full mark. In the mean time, there is no checking the 5 speed.
 
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