Originally Posted by Jerad

I'm in Canada and not sure which State you are in. Check on other auto discussion websites and see if anyone has posted useful information about these topics as applicable to your State. Or check with your State's BBB and they should be able to tell you what Laws are applicable to these kinds of situations.

You're right. It could be any of a number of problems, none of which is tied to service intervals. If you pay the $700 to the dealer and they find it is not lack of maintenance, will Nissan reimburse the costs? If it turns out to be lack of maintenance, and there are no laws to assist you, you will be left suing the garage that serviced it.

Of course, that Nissan is willing to pay you off indicates concern on their part. It is possible that your 3.5 has a latent defect that they are trying to cover-up without actually covering up.

To investigate this issue, you can sign up to download alldata.com's technical service bulletins for about $25. If you find some that could be applicable to your vehicle and which, if not corrected, could result in the engine sludge, then tell them that they have to prove it wasn't the defect which caused the incident in light of the fact you have the service records.

I suppose for anyone out there reading this - if you have a similar problem, and didn't have Nissan service the vehicle, get it auto-vac'd for $100 before taking it in on warranty service. That should clean the sludge out of the vehicle and make this problem a non-issue.

Good luck.