Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Extra quart of oil

I have a 2000 Mercury with 192K miles on it. Oil capacity re owners manual is 5 quarts. My mechanic filled it with 6 quarts saying that the oil filter holds a quart and it won’t be overfull and won’t hurt the car. The dipstick now reads right on max. Does filling it with 6 quarts hurt the car?

First, if the owner’s manual says that it takes 5 qts. W/FILTER CHANGE, that is what I would go with. I don’t think an extra 1/2 qt. would do any harm, but I wouldn’t overfill by a whole qt. I’ve never seen an oil filter big enough to hold a qt. The stated capacity of my Odyssey is 4.6 and I usually just throw in 5.

If your dipstick reading is right on, then the six quarts does no harm. Over the years I have noticed some variance between the published capacity and what makes the dipstick read at the max, and have had no serious consequences in adding up to the max, even if I exceed the published capacity.

No. It won’t hurt anything.

The oil pan in your Mercury has a double sump. The crossmember passes between the two sumps. The forward sump just holds extra oil and spills into the rearward sump when accelerating from a stop. The rear sump is where the oil pump is located. So an extra quart of oil in these engines is no big deal.

As long as the dipstick reads the oil level on the MAX mark, it’s good to go.


Are you sure your car doesn’t specify six quarts of oil when changing the oil filter. Every 4.6L I’ve seen car or truck specs 6 quarts.

I’ve had a few Grand Marquis, including a 2000. I remember that that the 91 and earlier which had 5.0L engines had two sumps and two oil drain plugs. One quart sounds about right for the front sump.
However, as best as I can remember, all of the 4.6L engines (including the 2000) only had one sump and one oil drain plug.
Six quarts does sound like the right number, but I can’t remember for certain.

As long as the dipstick reading is correct, taken on level ground with the motor off for about 5 min. prior to pulling the dipstick; then you are fine.

When I change my own oil I “underfill” it at first, usually adding 4 quarts. Then I run the motor for a few minutes. Turn it off and in a few minutes check the dipstick and then add oil to reach the full mark.

Running the motor fills the oil filter. The oil filter does fill with some oil, but it would be a big filter to take a quart, 1/2 qt. is more common.

Regardless, in this situation you are fine and good to go.

I did some more research, and it appears that for the first time since 1986, I was wrong. If you look at page 197 of the 2000 Grand Marquis owners manual, it calls for 5 quarts of oil with the filter change.

It won’t hurt your engine. But find someone else to replace your oil.

Every car I’ve ever owned in the past 40 years…in the owners manual showed oil capacity with and without filter.