Q: Rod Knock

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I purchased an extended warranty when I bought my vehicle (5 years/100,000 miles). On 10/26/16 the car made a loud knocking noise when started. I surmised a blown rod. I had it towed to my mechanic who confirmed this. I contacted my service contract company to file a claim. They have had my mechanic break the engine down and take pics and send to them, send them a video of the sound and also have sent out a 3rd party appraisal to find "the point of failure". They are now claiming they still cannot confirm this is whats wrong with the car and they want my mechanic to take the cam apart? My question is what exactly has to be done to prove a rod knock (blown engine)?

My car has 106835 miles.
My car has an automatic transmission.

Hello. This engine does have a series of common issues that can cause a knock. I have seen quite a few of them with rod knocks, but most of the time the issue is the timing chain. The warranty company is looking for the evidence to show where the noise is coming from. If it is a rod knock then the mechanic should be able to show them where the rod bearings are worn out causing the excessive clearance. If the bearings are fine then it is not a rod knock issue. The timing chain should have been checked for excessive slack before the engine was disassembled to see if that was the cause of the noise. Keep in mind that the warranty company is looking for any reason to either keep this repair as inexpensive as possible or even deny it if they find reason to. This really falls in the hands of your mechanic and what he can prove which should be an easy job.

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