Even so, I think Tester’s idea above to have the cooling system air bled is where I’d start if I had that problem.
If that doesn’t do the trick, and nothing else above, or it works then the problem returns in a few weeks, probably good idea to have the engine checked for a head gasket problem.
@vrebosch How many miles on vehicle when you first went to the dealer and what was written on your paper work when you picked it up. The part about not keeping records and the part about the way you drive just don’t sound right. Is this a Nissan dealership ?
There was 55000km on the car and a 60000km warrantee. Yes this is a dealership. The first time I brought it in they replaced the catalytic converter. And ever since then it makes this noise. It makes get be that my car sounded like a tank and I couldn’t hear it at first but as soon as they changed the catalytic converter lots of noises came out
About the records. The look of embarrassment on the service managers face was obvious that they messed up considering everything that they have done has not been documented.
Your use of kilometers leads me to think you are not in the united states. Has any one else heard the noise you are writing about. You should really contact Nissan because a Nissan dealer should document everything that is done to a vehicle warranty work or not.
It may be that you have to pay an independent mechanic to find the problem and send a copy of the diagnosis to Nissan.
Since you started to hear new noises after the cat replacement, good idea to have the shop double-check the cat heat shield installation. And the entire exhaust system’s hangers. If anything is loose it will definitely rattle, and it will usually rattle much worse at certain engine rpms than others.