Buying a Used Car -- Am I Nuts?!



I recently went to look at a 2014 Mazda2 with 55,000 miles on it. I took it for a test drive, where it performed admirably, and to a mechanic for a pre-purchase inspection. He said it needed a few things (brake pads especially) but that it seemed to him to be in good shape.

Before making an offer to the seller, I decided to pull the CarFax report (I know, I know – I should’ve done it sooner). There I found quite the surprise: at ~36,000 miles, the car’s engine was removed and replaced! Alarmed, I called the shop that effected the repair. The mechanic I spoke to assured me that the replacement engine was brand new, and had come straight from the Mazda factory. He replaced it, he recalled, at the behest of its then-owner – a rental agency – after a renter had driven it over some obstruction, punctured the oil pan, and continued to drive it without any oil. When I asked the mechanic if he’d have any reservation buying this car, he said “absolutely not.” In fact, he pointed out, I’d be making out well, considering the engine has only ~20,000 miles on it.

So I’m hoping to get some advice. Am I crazy to still be considering this vehicle? Would I be crazy to NOT consider the vehicle? Looking forward to hearing your thoughts. . . .


if work was done at Mazda dealer shop and engine was new, I see no reason to be alarmed, especially since mechanic does not see other issues.


Thanks for your reply! From what I can gather, the work wasn’t done at the dealership, but at a mechanic who frequently worked for this particular rental agency. Would this change your response?


at that point I would probably scratch my head and start looking at that particular shop reviews at Yelp, Google, etc… to find out if it was of the honest/reliable sort


I did look in to that: I found mostly excellent reviews.


I’d want to know more about the mechanic before I weighed in on whether or not you should be concerned about the quality of the engine swap based solely on where it was performed. There are plenty of independent mechanics (some on this forum) to whom I would take my car long before I set foot in a dealership, and the opposite is also true. Both dealerships and independent shops have their share of excellent mechanics, and they also have their share of morons.

As you probably will never figure out which one worked on that car, rely on your pre-purchase inspection. Quite frankly, engine swaps done wrong are often pretty obvious. Does it stall at red lights? Does it run rough? Does it flex like crazy due to poorly installed or missing motor mounts? Look around in the engine bay. See any speaker wire? Golf tees in vacuum lines? Wire nuts? (yes, I have seen all of these things and more in swapped cars).

If it runs fine, and doesn’t have anything stupid going on that you can see when looking at the engine, and your PPI mechanic said it’s good, then it’s probably good.

And assuming it’s good, the car has 55,000 miles, but the engine only has 19,000 miles on it, which is actually pretty great.


Well said, thanks!


I would pass myself unless I could actually see the paper work with the engine number and see if it matches the engine .


Alas, I’m not sure that’s possible.


I think you got good answers. I wonder if they stuck the customer with the bill for the engine?

My Pontiac was a rental that I bought current year with 36K on it. I’ve got about 130K on it now and couldn’t be happier. Wish I could find another one.

I don’t know anything about Mazdas though and my only question would be why they kept a rental in service for 55K unless Mazda has a 50K warranty. Normally they dump cars when the bumper to bumper expires.


I bought a 1990 Ford Aerostar in 1991 from a used car dealer. It had the balance of the factory warranty. At 36’000 miles the engine had to be replaced under warranty. New engine and no problems. I wouldn’t worry about a new engine. In fact, I would regard the engine as a plus.


I am a little skeptical , why would a basically self insured rental company spend the amount of money for a new engine on a vehicle they may have only paid 15 to 18 thousand for. Seems like they would just action the thing off .


It may have been covered by rental insurance, or heaven forbid the renter. I agree with your mechanic.


Maybe get an updated opinion from the mechanic you first took it to. Tell him what you now know or wonder about the engine and ask him to be especially vigilant about the engine. Shadowfax, above, has suggested some clues to be investigated. The right mechanic may actually enjoy doing this level of sleuthing, as long as you are paying fairly.


You may be crazy… but you’re definitely not dumb!
I commend you for having done all the right research and having done so before singing anything.

Net/net, it sounds like you may have found that rare really good used car deal. I wish you the best with this.


Is this the first time in the last ten years that CarFax is not worthless? Some regulars despise CarFax, stating that the information is often in error.
I have reviewed CarFax reports on my vehicles and those of customers and found the information interesting.


It just might be. In this case, the first I recall, the potential buyer actually did research far in excess of the norm and found that CarFax led to real information. I’m on e of those who’s seen too many totally erroneous things on CarFax reports, but I suppose even the biggest fabricator accidentally gets one right eventually. Sort of like the old statistics joke about sitting a dozen monkeys behind typewriters… eventually one will accidentally type War and Peace.


Toyota uses CarFax as a tool to sell used cars ans used car warranties. Perhaps they would like to hear from you how poor the CarFax service is.


CarFax has linked itself into almost all used car sales organizations now. And, since people ask for it, it’s become expected. Any used car operation without it is behind the times and losing business. Kudos to CarFax as a business for having integrated themselves into the used car industry the way they have.

But that does not make its access to data, or its accuracy, any better. If you choose to consider them an accurate source for cars that you buy, that’s your choice. I choose not to. That’s my choice.


I am not critical of each item on a Carfax report, I just find the vehicles history interesting.

Have you purchased a used car since Carfax has been available?