There are way too many things I cannot address, but I can offer some tidbits for consideration. There are some engines that are prone to failure from oil sludge, and it has nothing to do with whether or not it has a turbo. Chrysler, for example, has built a lot of really tough engines for a real long time. The 2.7L is one notable exception. Failures are almost always due to oil that isn't changed at exactly the recommended interval, and it is not turbo-charged. Toyota had an engine in the late 1980's or early 1990's that had its oil filter right between two exhaust manifold runners. They had a huge problem with oil coking from the high temperature from the exhaust system. Wasn't a turbo engine.
I have an 1988 Grad Caravan that has not had the oil changed in over fourteen years and 120,000 miles, to show my students what some engines are capable of. (That is not neglect; its abuse, and Iam obviously not recommending anyone else do something so stupid, but it sure proved my point). My engine also had a service bulletin related to the PCV system.
No engine is supposed to have blow by, but since it likely will, the PVC system is added to address that. If that system was inadequate, you would have had oil sludge problems before now, but how would you know? Sludge does not show up on the dip stick. It does not show up in the oil being drained. There is no easy way for you to know its there, so how do you expect the mechanic to know? There is only tiny oil supply and return ports visible when the turbo is removed. Any oil seen there is going to be dark due to being hot previously. There does not have to be sludge there for it to be dark.
From what I read here, there are two points to be considered. The first is you knew there was a sludge problem, and failed turbos do not cause sludge. You were continuing to drive a car with a known problem without addressing it with more-frequent oil changes. That is your fault.
The second issue is you asked to have the oil changed, which typically would be included in this service, if only for the extra insurance of a quality repair. We get accused all the time of trying to sell parts and services that are not needed, and we get called all kinds of names that cannot be printed here. For that reason, a lot of shops shy away from recommending anything that is remotely questionable, then we get accused of incompetence when we did not recommend or perform that service. I know the laws vary by state, but in most places you should have received a detailed repair estimate listing the symptoms and the planned course of action. When a part of the procedure is already known, (oil change), it is usually included in that list. Sometimes it is impossible to know everything that is going to be needed until the mechanic does some investigation and diagnosis, then the estimate may be provided over the phone. Either way, if "oil change" is listed on the written estimate, you have proof it was requested and should have been done. If it was not, that is the shop's fault.
You also said you are using synthetic oil. Given the current quality of additives in petroleum-based oil, the only advantage to using synthetic is they advertise a much longer time requirement for oil changes, often as high as 15,000 miles. Blow by still occurs at the same rate, and it accumulates in the oil and condenses in the oil filter and eventually plugs it. All oil filters have a bypass valve, either in the filter or in the engine. It is better to send unfiltered oil to the engine bearings than no oil at all. If you follow the oil manufacturer's oil change interval recommendations, you were likely running with excessive gunk in the oil, however, to achieve that higher mileage recommendation, there might be additives that take longer to break down. Those additives include detergents to clean products of blow by off engine parts, dispersants to hold the crud in suspension so it can be carried to the filter, and anti-foaming agents to reduce air from being whipped into the oil. Air in the oil can be compressed, and that reduces the thin layer of isolation between moving parts, mainly engine bearings and pistons The bottom line is the oil should be changed when recommended by the engine manufacturer, not the oil manufacturer. Even if the additives are not depleted yet, it is the oil filter that becomes plugged from condensed blow by, and that is the result of time the engine was running, not the amount of time the oil was in there. If you waited with regular oil changes until the oil manufacturer's recommendation, they always have stipulations, for legal protection, that must be known. If you did not know and / or follow those, I suppose someone is at fault, by I don't know who, (or whom! I can never get that right), or if that is even a contributing factor.
Look for an oil change sticker on the windshield or rear of the driver's door. Sometimes the oil change charge is buried in the flat-rate charge for the service and is not listed separately on the final invoice. You may have gotten an oil change the service writer who wrote up the final bill did not know about. From the business owner's standpoint, that is not a good way to protect himself for cases like this, but consider when wheels and tires are balanced, we do not charge for each wheel weight, they are included in the labor charge. Later, there is no way you can accuse them of not installing a needed weight and there is no way they can verify they did install a needed weight.
You did not include the most important detail, and it is doubtful you even know it. That is, how did each turbo fail? When you consider the very high temperatures they run at, and the very high speeds, it is amazing they do not have a much higher failure rate. You can expect to replace one two to three times as often as needing an engine rebuild, and it is not uncommon to need one near 100,000 miles. The issue is why did the replacement fail so soon, and did it fail for the same reason as the original one did? That is what I referred to in my first sentence. Also, why did a failed turbo cause an engine failure? If turbo parts became shrapnel, it may be necessary to remove the cylinder head to do an inspection, but if your car has an intercooler in front of the radiator, those metal parts would never have made it to the engine. On the exhaust side, flying metal parts would have gone down the exhaust pipe without causing further damage. If the bearings were torn up from lack of oil, the turbo simply would have stopped spinning or become ineffective from spinning too slowly.
If the turbo was a rebuilt unit, I suppose there could have been a problem with the way it was reassembled, but then how did it last for 12,000 miles? In that many miles, you should have changed the oil and filter at least twice, so when you blame sludge on the failure, the repair shop is long out of the picture. This is why I am not ready to lay blame on anyone yet.
Oops. Now, after rereading your post, I see you did indeed include a very detailed description of the failures that I neglected to consider. Sorry for forgetting that. You are going to have to pick and choose my comments to see which might have value or be related here. My best suggestion, rather than running to court and pleading your case to a judge who likely knows nothing about cars, is to ask for a meeting with the district representative. When I worked for a very nice family-owned Chrysler dealership, our district representative showed up once per month for exactly cases like yours. The service shop is bound by their franchise agreement as to what they can and can't do, what they can charge for, what they can give away, and especially the repair procedures they must follow. The district representative has a real lot more leeway, and he can authorize almost anything to solve the problem. The dealership owner or the service manager is your advocate so it's smart to be polite. We know you are frustrated, but no one intentionally tried to damage your car. Screaming customers get much less help. When a customer is considerate, the service manager is usually happy to set up the appointment to meet with the district representative. If you are told he only meets with people who's car is still under warranty, insist on a meeting anyway, in light of the service bulletin for the plugged PVC system. Some people refer to these as "secret warranties", but what is really happening is he might authorize the dealer getting a replacement turbo from the manufacturer at no charge, or anything from "no help available" to "do whatever it takes to get the car back on the road". You have to remember that he always has in the back of his mind that he needs to keep you happy so you will buy another Mazda. Also, it was a common saying at my dealership, "it takes more dollars for advertising to get one new customer than it takes to keep ten current customers happy. The dealer is going to be hoping the district rep. Comes up with a solution that makes you happy.
Friday, December 9th, 2016 AT 7:10 PM