(Apologies in advance for the lengthy post.)


2006 Infiniti G35 Coupe, 6-speed manual, 112K miles. I bought the car from a friend when it had about 50k miles. He had the car for the previous 30k miles. We are both sticklers for maintenance and both used synthetic oil (typically Mobil 1) exclusively.

This car has never burned or leaked a drop of oil.

I took the car in to Kwik Kar a couple of weeks ago for an oil change. While I was there, the mechanic recommended an engine flush. (I've since learned that this isn't really recommended for such a high-mileage engine.), as well as a power steering flush and something else I can't remember. (The receipt is in the glove box of the car, currently sitting at Kwik Kar.) This is the type of flush that involves flushing the oil with some sort of additive / solvent / ??, not the one where some mysterious substance is injected into the intake.

2-3 days after the flush, I noticed an obnoxious rattle when starting the car. Over the next couple of weeks, it got progressively worse. I took the car back to the same Kwik Kar. The (different) mechanic took me into the pit and said that the noise was coming from the catalytic converter. To me, the noise - insanely loud under the car - seemed to be coming from forward of the bell housing.

The mechanic noted that the oil was low (and very dark considering it had about ~1000 miles on it). There was no sign of a leak. I've also not noticed any smoke (of any color) from the exhaust at any time.

They added some sort of additive - white bottle with an STP logo - which they thought would help the noise. I'm not a fan of snake oil "solutions." I also asked how, if the noise was coming from the cat, an additive was supposed to help, but didn't get a comprehensible answer. (It didn't help.)

That was about 1 - 1.5 weeks ago. This morning, the rattle on start was very bad, and very noticeable when driving up to about 3k RPM. It is definitely RPM-related, not speed related. I (unwisely) decided to drive it back to Kwik Kar.

The Fun Part

The engine popped and vented several quarts of oil on the highway, and came to a thankfully drama-free halt. I had the car towed back to Kwik Kar (giving them a chance to look at it first).

I was told:

  1. There's no way an engine flush will cause an engine to blow. This seems odd to me since, if they flushed gunk out of the engine, it would wind up in the oil pan. There, the oil pump could pick it up, potentially clogging oil passages pretty much everywhere.

  2. Since I'd driven the car ~2k (total) miles since then, the flush couldn't have caused the problem. The mechanic (third one I've met) said I should have brought it back when it started making the noise. I pointed out that I had brought it back.

  3. The mechanic that initially worked on the car was off, and should return tomorrow.

In short, they were not very encouraging or helpful. I have little confidence that the original mechanic is going to admit any fault.

I would readily admit that some times things just happen on high-mileage car, but this thing has run like a top for the entire time I've owned it. It's never had an engine-related squeak or rattle. It seems highly unlikely that this would just magically happen following Kwik Kar's service.

Thoughts? What actions should I take at this point? A re-manufactured engine for this car is upwards of $3k, not to mention labor cost.


Kwik Kar is denying responsibility, and wants ~$9800 to replace the engine with a used one that has over 90k miles on it, claiming a 30% labor discount. I find it odd that they would offer a labor discount if they don't believe they're at fault, but such is life. I am disinclined to let them touch anything. (Their diagnosis is a thrown rod.)

City Garage quoted $7500 for a similar high-mileage engine. (I've had cars in there before and have always had a great experience.) The labor portion is about $2k (USD). After perusing the service manual, that sounds like a good deal, but the engine price is significant. I've found remanufactured engines online for $2k-$3k, but I haven't found a shop that's willing to install a customer-provided engine. So, I can save several thousand dollars, but it looks like I'll have to do the labor myself. (I've swapped engines before, but not on anything this complicated.)

If anyone knows of a shop in north DFW (Plano / Wylie area) that would be willing to take this on (install an engine I provide), please speak up!

  • 1
    IMO there's no way to prove with facts a claim that states their actions destroyed your motor. It's a belief but there isn't any evidence to promote the idea to a fact. Sorry about the occurrence, always difficult to lose a motor. Best of luck to you. Commented Jun 29, 2015 at 21:17
  • 1
    @DucatiKiller I get that. As an engineer, I'm disinclined to believe in coincidence. Especially given that I've never had an issue with this car until they touched it. The fact that their mechanic couldn't even figure out how to reset the oil life indicator was not confidence-inspiring.
    – 3Dave
    Commented Jun 29, 2015 at 21:30
  • 1
    Certainly not saying that incompetence was not involved. It's just a very difficult position you are in and coming up with any proof will be extraordinarily difficult. Very unfortunate circumstances for you. Feelin your pain. Commented Jun 29, 2015 at 21:41

3 Answers 3


It sounds to me as though they didn't put (enough) oil back in after the engine flush. First of all, it didn't need an engine flush. Mobil1 and other synthetics are renowned for not leaving deposits in the engine. I would bet your engine would have been sparkling clean on the inside. They sold you something you didn't need. (I'm betting something along the same lines for the power steering as well.)

EDIT: Secondarily, they may have never put fresh oil into your engine. They may have just left the flush in the engine without changing the oil or giving you a new filter. This, in-and-of-itself, could account for the lack of oil, the blackness of the oil when checked, and the degraded engine noise/performance you talked about.

Your best bet at this point is to see what they say and what they are going to do for you. If they say it's your fault, get a lawyer. If what you are saying is exactly how it happened (and I have no reason to doubt you), there is no doubt in my mind it is their issue.

As a side note, this is one of the reasons I never take my car to the Quickie joint to have the oil changed. The hire (for the most part) sub-par non-mechanics to do the oil changes. These people, while their heart is in the right place, get minimal training (yes, even a monkey can be trained to change oil correctly), and are in a position where their only need is to pump out vehicles. They overcharge on their oil, give you crappy filters, and try to get you to buy things you don't need. If this is something you cannot do yourself (ie: you live in an apartment where you are not allowed to change your oil, etc), find a local Mom/Pop shop which can do it for you. Take them the oil/filter you want used. Hang around if possible to ensure they are using your oil/filter and that it actually gets put into/onto the engine. I really hate craptacular service and the Quickie joints surely give it to you.

  • Thanks for the insight. I topped off the oil after they pointed out that it was low - they did not before returning the car - and the rattle got a little better. I'm not thrilled about hiring a lawyer given cost and how difficult it is to prove what, exactly, caused the failure. It was weird that they pointed out the low oil level and bad condition - not quite black but getting there - but didn't even suggest changing it again or at least filling it back to the correct level. :
    – 3Dave
    Commented Jun 29, 2015 at 21:29
  • @DavidLively - I understand the lawyer thing. Sometimes the threat of a lawyer is enough to make a difference. It is definitely the last chance scenario. Also, if you make the threat, ensure you will back it up. If the engine was running good prior to their service, then after the service steadily got worse, it puts the ball in their court. I will add one more thing to answer above. Commented Jun 29, 2015 at 21:42

I doubt you'll ever see this considering how old this post is, but for anyone that happened to run across this post I'll add my two cents. First off never let any of these quick lube places do anything more than an oil change. They work off of commission and often aim to get the customer to get added services that aren't even needed in the first place. Calling them mechanics is an overstatement if best. They certainly aren't ASE certified mechanics. Almost anyone will be hired to change oil. You're better off just buying something to drain the oil in and doing it yourself. Or you can always go to any tire shop and bring your own oil and they'll do it for $10-$15 bucks.

As far as getting an used engine installed, next time do your research. There's plenty of smaller mechanic shops, especially in the DFW area that will do it for considerably cheaper. I had an 09 Altima that blew a head gasket and blown up the engine. I found an engine at a junk yard in South Dallas with 56k for about $800. I also knew of a great mechanic that had a shop in Irving. I purchased the engine online and he went to pick it up for me. He did the install for me which came to about another $800 for labor. So it ended up costing me around $1,600 total to have an used engine installed. I had just purchased that car too and saw no need in getting another one. Those other shops were over charging you by thousands. I always prefer the smaller shops over the bigger ones. Downside is that it may take longer to get your vehicle fixed. Because they often have too many vehicles to repair and no employees. The shop I go to, it's just that guy and his shop. He always has a high workload due to the fact that he won't cheat you. He's fair and honest plus always does great work. So the fabled fair mechanic shop does exist. You just need to find them. I will never go to a big chain mechanic shop. I do most of the maintenance work myself anyways. I just didn't have the means to install an engine myself. Anyways hopefully ppl will learn not to trust any of those larger chains at all.

  • Thanks for the post. I wound up getting a JDM pull and swapping it myself. This required, among other things, converting a RHD engine harness to LHD, futzing around with the ECU for many hours, and a bunch of other stuff, but eventually it ran correctly. After driving it for a few months, I traded it on an old 4Runner which stubbornly refuses to have any problems whatsoever. I agree with you about the little shop vs big shop. These days, I do all of this stuff myself, but it's nice to have an honest, qualified, reliable shop nearby when something is urgent or requires a lift.
    – 3Dave
    Commented Jul 30, 2020 at 23:07
  • Yup me too, that's why I DIY all that stuff. Also, being able to Just Fix stuff... last month in the middle of Nebraska I heard howling from right rear, I had just repacked the bearings so I popped off the tire and spindle ... nope, bearings are fine. It literally took 5 minutes... turns out the tire was bad. Had a full size spare! Another time I felt a dragging caliper after the car sat 6 months... jacked up the car, exercised the caliper through its range of travel 10x, put it back, been fine since. Commented Jul 22, 2021 at 1:48

For anyone else reading this, an "engine flush" can be done by draining the old oil, filling up with new oil, going for a quick 100 mile drive, then draining and refilling again. It's not quite as thorough as a chemical flush, but it doesn't destroy the motor either.

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