Dealer Oil Changes - Over the full ine? How Much Is Too Much?

I have recently switched to a new Subaru dealer due to a move. The dealer changed the oil and the oil is about 1 inch higher than the fill line. My prior dealer would always fill it to a quarter-inch or so over the full line. In the past, many dealers from various brands I have used overfilled to as much an inch over the line. It seems a common practice.

My question is this: In actual practice does this cause trouble? I assume not since it seems to be common practice. I’m not asking about a one in a million chance of problems. My question is do the mechanics here know that this is a real issue in need of correction, and when they change oil, how accurately do they adjust the volume compared to the filled line? In case this helps, the distance from low to full marks in this car is about 1.5 inches. Thanks for your consideration of this question.

I don’t know the exact point of danger is on too much oil. I imagine every type of engine is different. I do know that too much oil can damage an engine. Personally I would not drive a car with the oil level 1 inch above full.

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Same here. 1 inch is too much for me.

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Agree… 1 inch is too much. The dealer seems to have a policy to add too much oil because of 1) ignorant owners who don’t know how to or just don’t check the oil and 2) the longer oil change intervals.

They may have found the engine can take an extra quart of oil with no issues so that’s what they add. Ask your dealer that question. I for one, would love to know what they say.


Thanks very much folks. I phoned the Subaru service dept and they said “Swing by any time and we will take you right in and correct it.” I will be doing that. I appreciate the quick responses very much.

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A quart over will hurt nothing and is actually beneficial. Two quarts or more I would do something.

What year model and what transmission? With Subarus and the motor oil being over the FULL mark I always wonder about the final drive being mistakenly drained and the engine ending up with too much oil.

This is a problem that Subaru even issued a service bulletin on at one time due to the number of botched engine oil changes and trashed transmissions.


Yet they never go as far as attaching a highly visible label on the “wrong plug” :slight_smile:

2016 Forester 2.5i Premium CVT. Thx I’m still gonna have it corrected. And in the future I will go back to my old habit of asking the service writers to put “Do not overfill engine oil” on the customer request spot. I miss my old mechanics, but they are now too far to visit.

The big potential problem is when the oil level is high enough that the crankshaft hits the oil and whips it into foam. As you might guess, this is not good. There was a thread a couple of days ago about a Veloster that had been overfilled and developed an oil leak. In that case, my gut is telling me the shop (Midas) put in 4 quarts or so without draining the old oil.

As for the oil being above “full,” that’s been the case every time I’ve had an oil change. Part of it is probably that oil is measured in even quarts while crankcases aren’t quite as obliging. For example, my Corolla has a capacity of 4.44 quarts. Nobody is going to measure and add 0.44 quarts, it’s quicker and simpler to round up to 5. Some shops probably also add a bit for good measure. In your case, an extra inch probably signifies an extra quart or less. I doubt there’s any cause for concern.

I have a trucker bud, gets oil changes for his, wife and 2 kids cars and always added an extra quart of oil after any change. Never caused him any problems, but some cars may be sensitive to a quart over. You will sleep better at night getting it to the proper level, nice catch.

You don’t even have to attach a label. Acura uses a standard hex bolt for the oil, but a square drive bolt for the transmission. Plus “Engine oil” is stamped on the oil pan. You would have to want make a mistake and take a socket off the ratchet to drain the trans. Of course my Pontiac has no transmission drain plug so no problem there.

way to go! :slight_smile:

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My question is are you checking the oil correctly. If not done right, it can easily read 1" over when it is actually correct.

Engine off for a couple of minutes (2 or 3). Pull the dipstick, wipe it off, reinsert all the way. Then pull the dipstick again. Read BOTH sides. Sometimes residual oil in the tube will transfer to one side of the stick making it look overfilled. Turn it over and you may see a dry line down the center of the stick to the correct fill line.

Subaru’s are bad about this BTW because of the shape of the dipstick tube. It has a sharp bend in it that oil pools in.

This is a very helpful tip, but Yes, I do it the way you describe. With the Suby, I find that if I start it and move it around the driveway cold and then put it away again and check the oil it reads low. I’ve learned to check it cold after it had been run a good distance to get an accurate reading.

When inspecting vehicles at work I find that about half of them have engines over-filled with oil. I believe that the lube rack boys and girls are filling the engine with the amount of oil that is billed on the repair order. Example, an engine may have an oil capacity of 6.4 quarts, the customer is billed for 7 quarts.

It seems that the service manager doesn’t want to be troubled with quality control or showing the lube techs how to look up fluid capacities. If 30 vehicles each day leave 1 quart over filled, at $9 per quart (the billed price for synthetic oil) the company loses $270 each day.

All I can add is that last oil change at Subaru dealer on my 2015 Forester they filled it about half a quart (as best I can tell… 3/8th inch above full mark on the dipstick) too high. If I have them change oil again I’ll ask them to be more careful.

not reading the other comments but most will say about 1/4 to 1/2 qt won’t kill the car. more will make it foamy and won’t pump well and cause damage. Just slowly open the oil drain bolt and wiggle it till enough slowly comes out and then close it up/tighten. Don’t take the plug all the way out or the fluid will come flying out.

Or you could just remove the oil filter, dump it and put it back on, that will remove about 1/4 to 1/2 qt depending on the size of the filter.

I don’t know about inches on a dip stick, but the area between the two marks or the hatch marked area represents one quart. To me if it is over maybe 1/8 of the mark, or 1/8 of a quart, or 4-8 ounces, that would be max for me. Of course after an oil change you have to allow time for the oil to circulate through the filter, and then time for the oil to drain back in the pan again. Of course it all assumes the all the oil was drained out in the first place. It sometimes takes a while.

If engine were overfilled with oil, the crankshaft rotation would aerate the oil.

This would cause the engine to start making one hell of a racket, as the oil pressure light turned on.

Here’s what aerated oil looks like.

I wouldn’t worry about it.