Overfilling Oil - Worst Case Scenario

I read several postings on the possible effects of overfilling oil, but wanted to get the informed opinion on my situation.

I have a 2000, Dodge Dakota, 3.9L V6 that I bought new, kept in good working order, and expected to own for some time to come. I took the truck to a popular national chain for a simple oil change. The truck was driven for short distances until the 175 mile, 5-day (post-oil change) mark when we we got on the highway. Suddenly, after 5 miles, the “check gauges” light came on, the oil pressure gage was seen jumping wildly between 0 and 40, and within 20 seconds (before the truck could be shut down), a rod came through the side of the engine. When I checked the oil level, it was approximately 1.5" above the maximum fill line on the dipstick, over the ‘r’ in “Do Not Overfill” (…and this was after we lost some oil on the road.) In addition, the oil was dark and had a burnt smell. Though no “foam” was noticed, there was a residue on the stick well above the oil level mark.

The popular national chain says they have no reason to believe their error was the cause of my misfortune. It must be a “coincidence” and that they have no knowledge that such a catrostrophic event could be caused by overfilling the oil. (They do admit to overfilling the engine with oil.)

Does anyone have any experience with oil levels 1.5"+ above the max-fill line. Your insight is of great value to me. I miss my truck!

If the oil is overfilled to the point where the rotating crankshaft comes in contact with oil, the crankshaft will aeriate the oil as it rotates. When oil is aeriated with air the oil pump can no longer pump oil throughout the engine so the engine is starved of oil and the oil pressure falls off.

From what you’re describing, it appears the oil was overfilled to the point that this aeriation did take place, and the engine damage was caused from overfilling the oil.


The engines that I have seen drastically over filled were smoking profusely from the tail pipe and running badly, often stalling at idle. None had a catastrophic failure. But then, none were 3.9L Mopar V6s. If a piston and a crankshaft throw are in the crankcase they would raise the level quite a bit. Was the engine running normally without smoking for 175 miles and then suddenly with no warning POPPED? The dip stick will have a residue on the length that extends out of the tube. Hydraulic lifters usually get quite noisy and cause a dramatic power loss long before a rod gets thrown due to oil foaming. The dark color and burned smell is puzzling. The worst overfill that I have cleaned up after had 10 quarts drained when it made it to the shop on its own power with the dipstick blown up out of its tube and oil sprayed up on the hood. It was a 4 cylinder Isuzu pickup.

"The popular national chain says they have no reason to believe their error was the cause of my misfortune. It must be a “coincidence” and that they have no knowledge that such a catrostrophic event could be caused by overfilling the oil. (They do admit to overfilling the engine with oil.) "

They are either idiots or just playing dumb & hoping you will go away. Tester is right. With the proper amount of oil in the engine, & with the engine running, the level of the oil in the oil pan is below the spinning crankshaft. Too much oil will cause the scenario Tester described.

Don’t get rid of the oil! Go to another garage & have them drain & save every bit of it. Or maybe do this yourself if you feel comfortable with this. Plus pour out & save what’s in the oil filter. My guess is it was at least 3 qts overfilled.

Call the local vo-tech school & ask to talk to an auto instructor. Now he’s not gonna go to bat & testify that the garage ruined your engine, but what he could do is sign a sworn affidavit stating that if an engine is overfilled with oil it will eventually be ruined.

Then file a lawsuit (if it comes to that)& with the affidavit & the fact that the garage admitted they overfilled the crankcase, coupled with the fact that you don’t have to prove beyond a reasonable doubt in a lawsuit, just to a “preponderance of the evidence”, you would probably win.


Edit: Once at the Chrysler dealer I worked at, a young mechanic forgot to put oil in a car w/3000 miles on it–after he had drained the oil & changed the filter. The customer made it 4 miles before the engine seized. Now this is with NO oil.

With the engine grossly overfilled, the spinning crankshaft will whip the oil into a foam like Tester indicated. Since foam is 99% air, and since the oil pump is only designed to pump liquid, there of course will be no oil pressure at times, & when the oil that’s not foamed up goes into the oil pump, you will have OK pressure.

This is why a grossly overfilled crankcase won’t ruin the engine right away. Joekota said it was 175 miles and 5 days after the oil change that the engine failed.

In 1994 we had a guy come in the garage with a late 80’s I think, T-Bird w a 351 CID engine that was making horrible mechanical noises from the engine. He had just had his oil changed at a fast lube place 4 days earlier. I found 10.5 quarts in the lubrication system as opposed to the proper 5 quarts. The engine was shot. This time frame from oil change to engine failure is in line with Joekota’s scenario.

An overfilled engine can also huff enough oil into the combustion chamber(s) to hydrolock an engine.
Since the oil will not compress this means that something is likely going to give. This can range from an engine locking up suddenly and suffering little or no damage to something major like a bent or broken connnecting rod.

Higher RPMs on the highway is when this most likely would occur. A catastrophic failure certainly can occur from overfilling the oil.

I too agree that too much iol by that amount can cause destruction of an engine, the reasons already having been defined.

While I place the blame clearly and solely on the shoulders of the skippy lube, I’d like to suggest that in future whenever work is performed on your cars you double check the work to the extent practicable before leaving the shop, even if it’s just the fluid levels. One should not have to do this, but it can save you lots of aggrevation and even money in the future. Trust but verify.

Sorry for the delay in information, work really interferes with life.

In response to Rod Knox,…yes, there was residue on the dipstick. I checked the oil on the side of the road, expecting it to be low. When I initually wiped the dipstick, it was sticky with a burnt oil residue all the way up (the tube length). It confused me at first, but is obvious in hindsight. (Foam and heat)

Anyway, Mr. Popular National Chain Manager is flaunting his ASE credentials and has blown me off completely. (Not even a refund for the oil change.) Fortunately, local small claims court has a $6k limit and 2yrs statute of limitations. More to come in a few months after my court appearance. If anyone knows of information that will support my position in court, it would be greatly appreciated. People need to know they have recourse.

Thanks to all who have reponded.

Shame on them for causing your problem. Double shame on them for saying it was not their fault. It was, pure and simple. ASE certification my left hind foot. The guy is trying to say he is smarter than the engineer who designed your engine. He’s not. If it calls for five quarts and had at least 1-1/2 quarts more than that, the foam killed your engine.

You may not need to go to court. Just show him these posts. He is outvoted, at least six to one.

See my iffy lube experience posted here about ten months ago here: http://community.cartalk.com/posts/list/2136790.page

I have not needed to go back, but will always remember to check my oil if I do have to.

The day you picked up your car (after ther oil change) what was the oil level then? OH you did not check,shame on you. Can you tell me the amount of excess oil that was put into your engine? this is going to be an important figure as how will a judge know if the position on the stick that was indicated also indicated a damaging overfill amount? Lastly,what is your explaination for the burnt nature of the oil left in the engine? this needs to be explained.Remember, you are making the claim that the overfill caused your damage so the burden of proof is on you.

The chain’s not going to admit anything is their fault as a matter of policy. If they forgot to put the oil in and the engine seized two minutes after you left the shop, they would still deny everything.
Did they cause the damage by adding too much oil? Your best bet is to ask the manufacturer. There is a warning on the dipstick. The manufacturer must have had a reason to add this warning.
The facts are, you went to a chain for an oil change, they overfilled your oil against the manufacturer’s warning (and admitted it), and the engine suffered damaged within 200 miles of the oil change. How do you think this is going to look to a small claim’s court judge?
Sue them in small claims court for the cost of repairs. Watch a few Judge Judy’s before you go.

I think you may have tipped the odds favorably with your description of the problem. I hope you have pictures too. The noise and the rapid catastrophic failure after that tells me that the rod bearing lost lubrication rapidly. If some of the other rod bearings show damage, I would say that the oil change people were definitely responsible for the damage.

If the oil change guy claims that all the rods should have flown off at the same time, or similar words, I think you should win because we all know that that is wrong. Judgement for the plaintiff for $3,000.

I have no faith in ASE certification. It doesn’t mean the people are careful. I always thought of it as a joke since I had three years and two months of trade school training.

Mileage on truck?? At this point, it’s impossible to tell exactly how much oil they put in the engine…If the rod actually came through the block, a considerable amount of oil could have been lost before all motion ceased…

If you are in the business of changing oil, then you MUST do these two things. You check the oil level BEFORE you change it and you check it again AFTER you change it. Saves a lot of grief.

OH MY!! WHAT A MESS! And you know what? “SHAME” on OldSchool for riding you about not checking oil after it was done. While it is a good practice to check it weekly, or everytime you get gas, you shouldn’t have to check it right after an oil change.

My point is, this is NOT a forum to scold people, berate people, or even belittle people. They come HERE in good faith and because they trust our expertise, opinions, and experiences. Coments as such may make individuals such as Joekota not ever log in again.

Keep it factual, helpful, colorful, but NOT scornful!!


A lot of people come here and post BS too…

  1. Avoid national repair chains.

  2. Whenever feasible double check when someone works on your stuff. Trust, but verify.

In my opinion, ok4450 was simply demonstrating what a judge would ask. That type of information would be required in order to make a good case in court and prove it was the fault of the oil changers.

There was nothing “scornful” about the post.

It was good advice.

One thing that I did not see mentioned was that the old oil may have not been drained, the filter was changed and then new oil simply added. It might be possible to verify this with an oil analysis. With that you should know also what the analysis would show for unused or very new oil.

If the filter was not changed, then this could muddy the analysis.

Was this one of the places that have all activity in the shop recorded? if yes you could expect that information to be shared if it supported the shops claim, not shared if it did not support the shops claim.

I often wonder why a company would venture into the oil change business. The profit margin must be pretty small (non existant if you do not up sell anything) and think of how many jobs must go right to pay for one that goes wrong (even if the shop is only paying an insurance preminum).

Some seem to think that all you have to do is post anything about a quickie lube place and all will be pulling for you, not so. If you post facts that leave no doubt that the shop is in error and you did your part in the quality control process I will be leading the way to get you made “whole” but until then the shop is only suspect.

I could see foaming oil causing bearing failure but it is not clear how overfilling could cause a rod to break, and break so suddenly.The first damage I would expect from over filling is oil leakage, then bearing damage (which would show upon inspection) not rod breakage.For rod breakage I would expect to find something that interfered with the travel of the rod or piston, like fuel or coolant in the cylinder. Perhaps enough oil could make its way into the cylinder and lock things up but I would expect while this was taking place the bearings were being damaged and would have failed much earlier than the time it would have taken for the cylinder to be force fed enough oil to lock things up.

Glad to see you’re not taking it lying down. I recommend you find a competent mechanic as an expert witness to bring with you to court - - it’d be pretty fortunate if the judge knew about oil foaming :wink:

While I’ve never personally seen a rod broken or thrown because of overfilling it’s certainly possible that it could happen.

I have seen several overfilled engines that hydrolocked; one of them being a diesel. The combusion chambers had enough oil forced into them that the engines slammed to a halt but in the few cases mentioned this happened at idle or very low engine RPMs.
There was apparently no harm done in those cases but at elevated RPMs on the road I could see a catastrophic failure due to overfilling.

In the case of the diesel, a tech had changed a head gasket and test drove the car about 1/2 mile before it started bogging down, making noise, and slamming to a stop; luckily at the shop entrance right a lunchtime. He told me (I was the foreman) about the problem, went to lunch, and never came back to work. Ever.