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Can it take 2 months for the oil pan plug to blow if loose?

We have a 2012 Hyundai Elantra touring bought brand new off the lot 20 months ago with 35K miles. Regular scheduled maintenance and this last week the engine blew on the interstate within about 2 miles of starting to rattle. Dealer at first said it was a rod that pierced the block and oil pan, but then changed that theory and said that the oil pan plug was not secured and is trying to blame the engine on either the last service which was two months ago or “vandalism”. So my question is, if the last service provider didn’t secure the oil pan plug all the way, could it take two months to dislodge enough to blow the engine? Also, we checked the oil three days before the incident and it was fine, and there is no evidence of oil leak in our driveway. And if it is not possible for it to go two months with a problem, then how do we get the manufacturer to take care of this? the car is still under manufacturer warranty PLUS we purchased additional bumper to bumper up to 100K miles.

So they’re saying the engine threw a rod because the oil drained out due to a loose drain plug. If that were the case, you would have seen the red oil pressure warning light come on around the time the rattle started. Did that red light come on before the engine blew, and if so, for how long?

And, who did the last oil change?

Two days, two months, it’s all the same. A loose drain plug might not get looser. Drain plugs falling out isn’t anything the manufacturer will pay for unless there is a chronic problem throughout a model line. They might not even pay then.

If the connecting rod hit the plug and knocked it out, there may be a chance to get it paid for. That’s not a likely thing to happen.

Yes, a drain plug can come loose after a few months if not properly secured in the first place.

So who was the last “service provider” as you refer to it?

Warranty (factory and otherwise) is for the repair of defective factory parts or faulty factory workmanship.
It does not and should not cover a human error made by a service provider. This issue would be between you and the facility that changed the oil.

Also, we checked the oil three days before the incident and it was fine, and there is no evidence of oil leak in our driveway.

To me, that rules out any problem with the drain plug. If true, then based on the info you provided, it appears Hyundai owes you an engine.

I’m with OK4450, as usual.
Was that “service” performed by the dealer? If it was, it’s theirs to eat. If not, it isn’t.

If the service was performed by a Quicky Lube, I recommend avoiding them in the future. They often use barely-skill kids (honest kids, but not highly trained) and often don’t allow time to be sure the work is done properly.

Not to mention,maybe someone already did but, did anyone check the motor to see if the oil pan plug was indeed missing after the fact ??? Not secured doesn’t leak oil catastrophically.
A tightened oil pan bolt won’t come out on it’s pwn/

So, let’s get this straight . . .

If the engine is damaged, the oil level was low, AND the oil drain plug was loose, the last shop to do the oil change is on the hook

I’m a little confused with the replies thus far.

The OP said he checked the oil level 3 days before this incident and the oil level was fine. And there was no evidence of an oil leak in the driveway.

How is it folks are focusing on the drain plug not being installed correctly (2 months earlier)?

I assume the shop that inspected the engine after the damage was done, saw that the drain plug was visually and obviously loose. Perhaps the threads on the bolt were even visible

There’s obviously no way that anyone can be sure remotely regarding what happened with the engine. But you could check your oil before starting a trip and have it be fine and have the plug fall out an hour later (or even 5 minutes) on the road and trash the engine. A loose oil plug will hold the oil pretty well - until that last thread lets loose and the plug comes out entirely. Then 4-5 quarts gushes out and it’s pretty much all over after that. Might a loose plug drip a little oil? Sure. Mine actually does drip b/c its rubber sealing cap is shot and I haven’t gotten a new one. But it doesn’t drip nearly enough to leave any evidence on the ground. I think its pretty easy for a loose plug to go unnoticed until the final catastrophe.

In our fleet, we do oil changes every 6 months

My colleague racked a vehicle that was in for a service. The oil level was fine, but the drain plug was loose, presumably from 6 months earlier

Thus I ask the question. again. Did anyone check to see if the plug was missing, not loose, missing as just being a little loose, means nothing in cars I have had. Oil drips out slowly.
If the plug is still there, it’s a motor and not a service problem. And, if the dealer clams the plug was loose…that’s not enough. The dealer is out any money for fixing this car as he gets reimburse for it. He gets paid for all warranty work he does.

Stuff happens, yes it is possible for a drain plug to blow out after 6 months of faithful service. I would lean towards a little lose at the beginning, and it held for a while, but not long enough.

The fact that the oil level was full 3 days before this incident means nothing. Of course it will remain full until it gushes out in seconds due to the plug falling out.
An oil drain plug can fall out 2 months later; just like a spark plug can blow out 2 months later, an improperly tightened alternator mounting bolt coming loose, or whatever else fits the scenario.

What the OP needs to do is provide the info about the last outfit to change the oil.

Even if the last company to change the was the Hyundai dealer that does not mean that corporate Hyundai is on the hook for a new warranty engine. It means the Hyundai dealer is responsible out of pocket for it.

It’s possible I suppose. But it seems like if the drain plug was loose the oil would start to leak out slowly at first, then maybe over the course of a week or two start to leak out more and more. But the OP claims the oil level was ok 3 days prior. I wonder, does this mean it was at the “full” mark, or somewhere between the “full” and “one quart low” mark? And is the car parked in a spot where an oil leak would be noticed? It all seems sort of hard to believe, but I guess an oil drain plug staying in for 2 months, then working loose and rapidly loosing the oil more or less all at once is at least theoretically possible. But it seems unlikely as an explanation for what happened to me.

Cig’s description is what my understanding of the OP’s description is.

I think it is easier for a seriously overtightened drain plug to suddenly blow out after 2 months than an under tightened one. Surely the oil pressure light came on before or at the same time the engine started rattling. You should have immediately pulled on the shoulder, shut it off and checked the oil and called a tow truck.

Thanks for all of your information so far. The last service was at Walmart, two months ago. I live in a small town and there are not many choices. The dealer is not saying that there is any problem with the rod now, only that the oil pan plug was not properly secured and they think that is how the oil drained and the engine seized, ergo, “not our problem”. The check engine light did not come on until the very last minute. When driving the rattling started low and got progressively louder and within two miles I was on the side of the road BEFORE I lost all power. I knew there was a problem and pulled over and turned the engine off, but then it would not turn back over. So ultimately I am stuck either fighting Hyundai, Walmart or my insurance company? I am not sure I like this end of the deal…

The progressively louder rattling and the oil pressure light coming on before the engine seized are consistent with loss of oil due to the drain plug coming loose. It’s also possible to lose oil through the oil filter gasket if the oil filter was loose or improperly installed. Have they checked the filter seal?

And it sounds like the dealer is now saying that no connecting rod broke, only that the engine seized? So if no connecting rod broke, there’s no way the engine spontaneously self-destructed. It just plain ran out of oil.

It sounds like you’re left fighting Walmart. Get a written statement from the dealer on their findings, and a closeup picture of the drain pan with the drain plug loose.

I would also try to very the condition by refilling the crankase with oil and seeing if you can reproduce the leak through the drainplug. Of course, this is only valid if no one has touched (tightened or loosened) the plug since the incident. If you could make a short video clip of oil leaking from the plug, that might bolster your case.