Car Conundrum! Confounded by Conflicting Conclusions!
September 18, 2017 10:26 AM   Subscribe

We recently bought a used car that we expected to last us about 5 years, with reasonable repairs needed on occasion. But just a few hundred miles into our ownership, it started having engine troubles. We have two mechanics’ differing opinions as to the seriousness of said troubles. We are trying to decide whether or not this car is worth fixing. YANMM, but some additional perspectives would be nice. Saga after the jump.

We bought a 2010 Scion xD for around $6000 about 2 months ago, with 128,700 miles already on it. Body in good shape; CarFax showed minor front-end collision (backed up by a couple of chipped paint spots and dents); ran good on test drive; passed initial inspection with no cautionary notes. (Although the inspection was done same day by the dealer’s preferred mechanic, so that’s not surprising.) The car did not come with a warranty.

After driving about 200 miles, the Check Engine & Vehicle Stability Control lights came on.
We took it in to MECHANIC #1, who diagnosed engine misfire due to two bad ignition coils. Also noted that all spark plugs were originals, so 7 years old. They recommended replacing all coils and all plugs, in case the parts in that array that hadn’t failed yet were close to doing so. We agreed, and dropped $750 for parts and labor.

Everything seemed fine until about 400 miles later, when the same lights (CE & VSC) came on again, and we noticed the engine occasionally running rough when we were stopped.

We took the car back to MECHANIC #1, who provided what we felt was a pretty extreme diagnosis, so we took it to MECHANIC #2 for a second opinion. They reached a different conclusion.

- - - - -
MECHANIC #1 diagnosis & recommendation:
Computer codes indicated misfire. Performed dry & wet compression tests.
One cylinder showing about 1/3 of acceptable pressure (~50/150/150/150). Believe there is a leak at bottom of the cylinder which is underperforming, as introducing oil temporarily sealed the leak and brought pressure up.
Recommend complete engine rebuild.
Quoted $5600 for engine rebuild, (parts + labor,) which would come with 3 year / 36k mile warranty.

MECHANIC #2 diagnosis & recommendation:
Computer codes indicated misfire. Searched wiring harness for shorts. Probed for voltage drop. Performed dry & wet compression tests.
Compression a little low (~125) across the board, but no one cylinder drastically underperforming as described by MECHANIC #1. Performed engine smoke test, witnessed leaking at top of cylinder #2. Believe vacuum system has lost integrity.
Recommend replacing oil pan gasket, valve cover gasket, and valve cover seals.
Quoted $210 for gasket & seal replacements, (parts + labor,) which would come with 1 year / 12k mile warranty.
- - - - -

Both mechanics have good reputations. Both were very willing to explain their process and findings. Both made good arguments for their recommended course of action.

If we believe MECHANIC #1, we were sold a lemon whose repairs will end up costing more than the purchase price, and we should go after the dealer to either buy the car back or pay for repairs.
(My gut feeling about this mechanic is that they do like to be thorough, and while they may not be shooting for the expensive solution out of dishonesty, they are next to a more tony neighborhood and may be used to clientele who don't look for second opinions and who don't mind throwing money at problems.)

If we believe MECHANIC #2, it’s not that big a deal. We will have spent more than we’d like to repair a car we just bought, but not SO much, and we’ll probably be fine to keep driving this car.
(My gut feeling about this mechanic is that they are more pragmatic and tend to fix things incrementally, as they are in a more blue-collar neighborhood and their clientele just need their cars to work.)

YANMM, but: Who should we believe? What should we do?
posted by D.Billy to Travel & Transportation (14 answers total) 1 user marked this as a favorite
 
Take it to an actual Toyota dealer (Scion was owned by Toyota) and have them run a proper diagnostic.
posted by Wild_Eep at 10:44 AM on September 18, 2017 [2 favorites]


If you can wrangle the dealer to cover your costs solution 1 incorporates solution 2 and you get an engine warranty. It's unlikely IME that'll happen but trying doesn't cost you much but some time and stress. The Dealership is also likely to run their own diagnositics before shelling out so that'll get you a third opinion.
posted by Mitheral at 10:48 AM on September 18, 2017


we were sold a lemon whose repairs will end up costing more than the purchase price, and we should go after the dealer to either buy the car back or pay for repairs.

In New York, the used car lemon law doesn't apply to cars sold with more than 100k miles. You can always ask, but I wouldn't expect much.

Seconding Wild_Eep, take it to a dealer and get it diagnosed. If it needs a rebuild you might look into getting a used engine put in instead. There are lots of shops that specialize in importing used JDM engines from Japan, and it was pretty cheap when I did it with my civic... maybe $2,000 for the engine and install would be a good price nowadays, not sure though.
posted by Huck500 at 11:00 AM on September 18, 2017


Best answer: A compression test isn't a subjective thing. Either one of the cylinders is way down on compression or it's not, and the fact that two mechanics got such wildly different measurements is a cause for concern. Issues that cause such large compression drops aren't things that come and go.

If it is #1, it is going to be VERY difficult to get compensation from the seller because, well, there's no recourse for that unless they gave you some kind of warranty in writing. If not, all of the car's hidden problems are yours once you sign on the line. This is why used car dealers are the scum of the earth.
posted by hwyengr at 11:12 AM on September 18, 2017 [1 favorite]


I wouldn't go back to mechanic 1, a set of 4 coil packs is under $100, and a set of 4 spark-plugs should be no more than $30.

Dunno what mechanic labor in your area costs, but doing that replacement is something like remove 6 screws, unplug 4 coil packs, unscrew four spark plugs, screw in new spark plugs, plug new coil packs in, and replace the 6 screws.
posted by gregr at 11:24 AM on September 18, 2017 [3 favorites]


Response by poster: Thanks for the thoughts so far! Please keep them coming.

hwyengr: Is it possible that inconsistent vacuum caused by bad seals & gaskets (diagnosed by M#2) could result in the different compression readings?

Huck500, Wild_Eep: I've hesitated to go to a Toyota dealer thus far because literally every Toyota dealer in (or just outside of) the five boroughs has a terrible reputation for service. But maybe it's worth looking a little further out. There's one 30 miles away in Mamaroneck that looks better. Although if the worse of the two diagnoses is true, it might be a bad idea to drive there!

In terms of getting help from the dealer of purchase, we know that without the lemon law on our side, our only hope lies in (A) basic decency which we're not counting on, or (B) fear of bad reviews and legal action. Which we are prepared to get into, but obviously would rather not.
posted by D.Billy at 11:30 AM on September 18, 2017


Best answer: The only gasket that could impact compression is the head gasket, and there would be a whole other slew of symptoms that would appear if that were the case (overheating, oil in the coolant, multiple low compression...).

Compression that low (50psi when it's supposed to be 150) can only be caused by broken piston rings, severely burnt valves, a hole in the piston, or incredibly deep gouges in the cylinder wall. If he says it's fixed with oil, that would rule out burnt valves but since mechanic 2 says the compression is fine, I really don't trust mechanic 1 in the first place.
posted by hwyengr at 11:39 AM on September 18, 2017 [1 favorite]


I would not do an engine rebuild on this car for that price. I also seriously doubt you actually need an engine rebuild.

I would probably take it to a Toyota service department for diagnosis and see if they agree with either of the two opinions. For example, they may agree that there is a vacuum leak and propose a course of work similar to that of mechanic #2. The advantage of dealers is that they see a lot of the same cars and are in a position to know about problems common to particular cars.
posted by everythings_interrelated at 11:49 AM on September 18, 2017 [1 favorite]


210? I'd basically take that risk and have them do the work, and then those seals are new. Maybe find a Toyota/Scion discussion board and ask.
posted by theora55 at 11:57 AM on September 18, 2017


Best answer: Did the initial mechanic replace the spark plug wires, when he did the plugs? Those wires can be everything, seriously. One cylinder running badly can be the one bad wire. But hey, what do I know?
posted by Oyéah at 12:41 PM on September 18, 2017 [1 favorite]


Response by poster: Oyéah: The spark plug wires were not replaced, to my knowledge. They weren't discussed, and aren't listed on the work order. I'll ask Mechanic #2 about them.

gregr: Yup, looking around now, (which I wish I'd done before,) the most expensive coil set I can find online is $422. Most are less than half that. We were charged $480 by Mechanic #1. The plugs cost us just over $115. Confirming my suspicion that this mechanic pushes “the best” because his customers (like this dingdong) will pay without thinking. The going rate for labor around here is around $95/hr.

ALL: I agree that getting a Toyota dealer's opinion is a good idea. It's feeling more and more like Mechanic #1 was less than trustworthy, and it seems smart to do a “best of three” on this.
But even so, I can't shake one thing the first mechanic said: “Do not drive this car on the highway, the engine could suddenly shut down on you.”
If the car is up to it, we'd like to visit family 500 miles away at the end of this month. But we'd hate to learn the hard way that dude #1 was right and we were wrong to discount his diagnosis.

Thanks again, friends. I'll leave the question open for a couple more days.
posted by D.Billy at 7:49 PM on September 18, 2017


Best answer: Honestly? I think Mechanic 1 is fucking you big-time. $650 for parts and labor for installing coil packs and spark plugs in a 2010 xD is nuts. The engine for your car--well, you take the engine cover off, if it even has one, and you can literally see the coil packs sticking out the top of the engine block, and the spark plugs live underneath them. You unscrew a couple of bolts, and they wiggle right out. If you've put together IKEA furniture, you can do this yourself.

Stick with Mechanic 2. If you want a second opinion, forget the dealer. Get an ODBII code reader yourself, run it on your car, and google the codes. You can get these at Autozone/Pep Boys/Amazon.
posted by radicalawyer at 8:09 AM on September 19, 2017 [2 favorites]


Response by poster: We're going to start by taking Mechanic #2's recommendation to replace the gaskets & seals to restore vacuum. Fingers crossed that'll do it. We'll ask him about the spark plug wires, too, and will probably grab ourselves a code reader.
posted by D.Billy at 10:25 AM on September 20, 2017 [1 favorite]


Best answer: Having recently replaced my ignition coils, spark plugs, and replaced a leaking cylinder gasket in my Mini, I'd recommend buying an extra coil, an extra spark plug, a couple spare quarts of oil, a socket wrench, and the right kind of socket for removing your spark plugs. Keep those in the car. Then, if another gasket leaks in a different cylinder, you're all set for doing a repair on the side of the road, and you won't be stranded or at the mercy of a tow.
posted by culfinglin at 4:13 PM on September 20, 2017 [1 favorite]


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