Depending on which seal is leaking, they could have disassembled the engine to get to it, and poked a hole in it. That would take considerable time. If the oil change was done at a speedy-lube place, they don't do engine repair so there would be no point in purposely causing damage.
On a lot of engines it is common for old oil to run all over the engine when the filter is removed. That's due to the design and difficulty in getting to the filter. That oil can also be very hard to clean off so most people just let it burn off later but it usually doesn't cause a lot of smoke. Most mechanics don't wash it off with engine degreaser and water for fear of causing other electrical problems which are also common.
At the far extreme of coincidence, if a seal or gasket is going to develop a leak, that can happen unexpectedly anytime. The question is, where is the car when that happens? If it just had the oil changed, you blame the mechanic. If it happened in the middle of a two-hour drive on the highway, you blame the person who worked on it last a month ago, or you realize it's just a normal occurrence that needs attention.
While coincidence that it happened just when the oil was changed is certainly possible, it does stand to reason something happened there, but it very likely was not intentional. The first thing to do is determine where the smoking is coming from and clarify what you mean by "profusely". To some people "profusely" means they can see a tiny wisp of smoke if they look closely. To others it's not that bad if they can still see the car behind them.
If the smoke is coming from the tail pipe, the oil was likely over-filled. Draining some out until it hits the proper level will solve that with no damage to the engine. If it's leaking low near the bottom of the engine, spilled oil may be burning off or they might have "double-gasketed" the oil filter. That's when the rubber o-ring seal from the old filter sticks to the engine and gets overlooked, then the new filter and gasket is screwed on over the top of it. Usually the old gasket will blow out well before the car makes it out of the shop, but that doesn't result in smoking. That just results in a huge mess on the floor. It has or will happen to every mechanic sooner or later. The only harm done is embarrassment.
If the smoking decreases the longer you drive the car, it most likely is just spilled oil. If it continues, have it inspected at a different shop and have their diagnosis put in writing. Don't mention the name of the shop that did the oil change so you don't sway their diagnosis or judgment. If the two shops are friends, the second one might tend to downplay the importance of their findings. If they don't like each other, you're going to be in the middle of them blaming each other for causing additional damage. Just get an unbiased opinion as to the cause of the smoke and what could have caused the problem.
Also be aware that some people run into problems when they have the oil changed at whichever shop has a sale this week. They all use different brands of oil that have different additives. Because oil fills the many passages in the engine, only about 80 percent of the old oil drains out during an oil change. Some old oil with its additives remains and those additives are sometimes not compatible with the additives in the new oil. In particular, rubber seal conditioners could break down and allow seals to start leaking. Those are going to be slow leaks and they will take days or weeks to develop. That's more common on high-mileage engines and is not going to happen as soon as you leave the shop. Those leaks will be slow and usually are only noticed as spots on the ground where the car was parked.
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Thursday, August 11th, 2011 AT 7:59 PM