I purchased my 4th series BM from the BWM AG dealership in Germany, where it was returned directly after the end of 3 years lease (warranty). The dealer/seller offered an additional one-year warranty. Faithful thou, it was not BMW AG extended warranty, but another solution.
In Germany, a warranty, actually insurance against technical damages, is widespread. The seller pays several % of the vehicle’s value to the insurance company, which covers the repair costs if something is damaged during the insurance period. In my case, the insurance company is Zurich, which has re-insured its risks further. Accordingly – I don’t have to worry that because the car was purchased in another country, that dealership would reorganize or “disappear”.
This is how the warranty/insurance contract looks:

I purchased the car, which had only 2 oil changes performed. When driving on Germany’s highways (the average car speed was 60 km/h) – not a big thing. I believe that anyone, who understands something from the cars, will confirm that it’s just like a “warm-up” for the BMW. But still – the car has had some troubles with the engine performance. The car has had the spark plug replacement “outside the schedule”. I replaced the spark plugs once again and fought their carbon residues. I updated the DME software and readapted the engine. Part of the problems disappeared, but still, some unevenness in the engine performance was present. More about the symptoms in Part 2.
The symptoms were present, but confirmation of the problem – no. But, I got lucky. Less than two months before the warranty ended, BMW AG issued the newest release of the ISTA, in which the expert mode for the VANOS hub appeared. The VANOS test module also was upgraded. Both these tools allowed me to immediately identify the problem. The problem is – due to rare oil changes; VANOS management valves are clogged. The problem is not complicated, but still – to replace the valve, “half of the engine” has to be dismantled. If for previous generation engines this repair could be done in 10 minutes, then for B series engines – 12 special tools are required, and the work takes a full working day!
It became clear that I would gladly trust this repair to the dealer, but the cost coverage – to the warranty insurance.
I prepared the technical information, with which I immediately introduced the seller of the car. It was crucial to not lose even one day to avoid the expiry of the warranty. The car’s seller sent the insurance company’s contact information in one day. The next day, I approached the local dealership Inchcape Latvia with the problem application. I submitted the following information:
a. description of symptoms of the problem;
b. printouts of the Expert mode graphs with explanations;
c. request to perform the VANOS hub test module (functionality check with the dealer’s diagnostics tool).

I the picture – documents for the dealer’s technical personnel.
I will briefly describe the sequence of events – just to clarify the approximate amount of time and energy consumed.
Had to wait for two weeks for diagnostics at the dealer center.
During the diagnostics, the dealer:
a. did not analyze the Expert mode data supplied by me; did not perform the hubs performance analysis (obviously, Expert mode is typically used only by the BMW AG engineers themselves);
b. the dealer performed the test module procedure and established that the VANOS hub could not successfully carry it out. It was good news (for me) – so the problem is still present!
c. an employee of the dealer center performed the test drive but did not detect the case of uneven performance.
The good news – the test module failed. Inchcape Latvia got in touch with the warranty insurer.
During the next stage, the warranty insurer asked to perform additional diagnostics to clarify the cause of the problem. Dealer’s specialists performed one more diagnostics, during which the oil pressure check was performed. It is logical because the performance of VANOS is ensured by oil. I had to wait additional two weeks for this second diagnostics session.
The oil pressure check did not indicate any problems. Verdict of Inchcape Latvia specialists (ISTA also defines it) – the VANOS hub solenoids and management valves should be replaced. The judgment was sent to the insurance company.
The insurance company did not give up so easily. Even though I reported the problem before the oil change, the insurer asked to supply the documents, when/who/how/with what/why performed the oil change (during this month, when both diagnostics were completed, I changed the oil in the engine). During 24 hours, I supplied the requested documentation. I waited for the insurance company’s decision for more than one month.
I received a favorable decision almost three months after the problem was reported. The “case” of my problem has reached 40 .. 50 pages. Finally, it was time for repairs.
In the image: list of the replaced spare parts

Along with the service costs, such a repair would cost EUR 1200 for a customer. Saved EUR 300 (two additional oil changes outside the “standard” intervals) results in the defect of -900 EUR. BMW is not the car on which to “save” money! Oil change intervals of 30 .. 35’000 km are not correct even in highway mode!
In conclusion – an interesting nuance. The insurance company covered the following expenses:
a. repair work – 100%;
b. spare parts – 80%.
I don’t know exactly why the spare parts coverage was reduced to 80%. Inchcape Latvia suggested that it could be because the dealer did not perform the last oil change.
My (additional) versions:
a. in the estimate, Inchcape Latvia included the spare parts by the list price (with a formal 15% discount), even though actually the problem appeared while all operation requirements – the oil change intervals were not overreached;
b. the damaged element was not known precisely (solenoid, valve, or both); but all possible “culprits” were replaced;
c. the defect of the VANOS intake camshaft was not mentioned in the initial application; its problem appeared only during the test (in addition, the test sometimes even was passed).
In addition, the insurance company refused to cover diagnostics costs. Accordingly, both diagnostics were covered by me.
In the picture – my co-payment for the spare parts for the repair:

Sentence of this entry – if someone believes that the insurance and/or warranty means zero problems… You are wrong! Keep in mind that I identified the problem by myself, prepared all the technical information; I wanted, and stood up for my rights. Despite this, all processes took three months; I had to spend several days in the dealer center and pay a co-payment of around EUR 250.
It seemed slightly comical that this case for EUR 1200 has so many human resources spent. I am sure this event’s administration took more resources than repair/insurance costs.
On the second part – symptoms of the problem; technical data before and after repair; description of the results.