Urgent: Too Much Engine Oil?



Hi Everyone,

I have a very urgent question. I just took my 2005 Mazda 3 to the dealership today for an oil change, and drove home immediately because I was in a hurry. I felt like the engine sounded different, but I didn’t really notice an impact in driveability.

So I get home, the car sits for three hours, and then when I check my dipstick, the oil level is simply off the charts. The mark goes straight past the Max indicator all the way up to the first crimp in the metal.

What sort of damage was done from driving? And what should I do? I don’t want to drive it back to the dealership for fear of further damaging my engine, but even if I could drain some of the oil, if I took it back like that, they’d claim there wasn’t a problem. What sort of diagnostics do I need performed?

I am absolutely livid right now, but I don’t know what to do. Thanks in advance for any help.


First thing to do is call the dealer and report this happening. Take a picture of the level on the dipstick for evidence. Then either follow the dealer’s instructions or drain the oil until it’s low enough to drive.

If the oil in the crankcase gets too high, the wind tossed off the crankshaft lobes can aerate the oil. In cases of extreme overfill, the lobes may actually whip the oil, creating a frothy mixture of oil and air. This can cause oil pressures throughout the lubrication system to drop. If this car has full instrumentation, then you would have noticed a drop at the oil pressure gage if this were happening. IF it only has a light, it probably wouldn’t come on.

All in all, the damage is probably not so bad. But don’t do anything until you call the dealer and report the problem. You could invalidate any warranty, and even if there is no warranty, the dealer is responsible for any damage to the engine that results from your drive home because you weren’t aware that they overfilled the crankcase. If you drive it now without consulting them first, you may release them from liability because you operated the vehicle knowing something was wrong.



Matter of fact, you probbaly have limited to no damage resulting from this, thus far.

-Matt (adding on)


Yes, that’s what I worry about, the oil being whipped into a froth and wreaking havoc on my engine.

Great info, thank you.


Check the transmission fluid level…


What Red Knox is trying to tell you is that if you have a manual transmission, they may have drained it instead of the engine. If you have an automatic, you don’t have to worry about that as you would not have been able to drive it.

If you have a manual however, then make the dealer come and tow your car in on a flatbed. The different sounding engine may well have been your transmission bearings and to drive it will do serious damage, if its not already done.

BTW, this actually happened to my mother once.


Crap, that’s a great idea too. I DO have a manual tranny…


This does not address your current problem, but in the future you may want to consider:

 Dealers are no better (or worse) than independent mechanics for almost anything you might need done on your car.  They will almost always charge more per hour and often more for parts and supplies.  They also tend to look at repairs a little different than the independent. 

A dealer may well recommend work that strictly may not be needed, but could be connected to the problem or maybe replace a part when a little repair would fix it ALMOST as good a new.  

There is no need to bring your car to the dealer for any service other than service that is going to be paid for by a recall or original warrantee. 

I suggest that most people would be better off finding a good independent (Not working for a chain) mechanic.


rod is right check trans first call dealer take pics, because you know dealer never makes mistakes ha


hold on, dont freak out, let your motor cool very good, wipe the dipstick off, and read it again. if it is still overfull, then drain some out, make sure no oil is leaking out of any gaskets and if it isnt you might be fine.


Thanks for all the comments.

As it turns out, I had the dealer call a tow truck to fetch my car (flatbed only, at my urging), and indeed, they acknowledged that they overfilled my crankcase.

They claim that all other fluids, my transmission, and my engine are okay. Fingers crossed.


They probably forgot to drain it before they added the oil.


Good, they did the right thing. The flatbed would have limited any damage to the transmission (and saved them money) had they drained it by accident.


Overfilling the crankcase is very common due to several reasons but the mechanic who failed to pull the dipstick to confirm that the correct amount of the proper fluid was added is unprofessional. Can I assume that the dealer has a dedicated “quick change bay?” Such bays seldom have real mechanics. If the first priority is price, where does quality fall?