I recently purchased an 03 M45, 52,000 miles, and prior to the purchase drove the car to the Infiniti dealership for inspection. They actually offered to perform the inspection for free!

Anyhow, everything checked out OK according to the mechanic. I was presented with an inspection sheet and the only outstanding areas were radiator flushing, transmission flushing and cracked belts. The belts needed the most immediate attention, so this was discussed during the bargaining session (From $17995 to $15900) and the car dealer was good enough to replace them along with draining the radiator. The transmission on the other hand is a different story and I opted not to proceed with this as a precaution. Can someone provide some information on the proper way to do this? What should one be mindful of? I undertand that the NISSAN Matic J Automatic Transmission Fluid is required. Is this correct?
I plan on visiting the Infiniti dealership shortly to complete this process, but would like to be armed with some data from this well-informed community.

On to my current problem. I recently noticed, after a short trip, and after parking the car in the garage, strange metallic pinging sounds eminating from the entire car. My guess would be the catalytic converter is playing a role here, but I've never heard these sounds from any other vehicle I've owned (98 Honda Accord, 93 Acura Integra).

These strange sounds last for a good 5-10 minutes I'm guessing. I've now paid closer attention after each time the car is driven, and to my dismay I continue to hear the same sounds each time.

Question: Is this normal for these cars? Should I be concerned?

I did not purchase the extended warranty from the dealer because I wanted to pursue a better warranty from Infiniti dealership. I was planning on waiting a month however. Is it already time to revisit that idea?

Thanks.

Modified by Calvenn at 9:56 PM 7/22/2008

Which of the above would be a more natural and realistic fit? (closer to spec = 235/45 18)

The following, I assume, should also be a factor. My current setup is 245/35 20 with approximately 1.5" gap in the rear and slightly under 1" gap in front. As you can imagine, I will be switching to 18" stock wheels in the winter.

Glad to hear you are happy with the Dunlop Winter Sport tires...I just took a chance and bought a set of those mounted on 18x8 ASA JH3 wheels last week on ebay from a guy in Madison, WI that had them mounted on his G35 sport. I put them on this past Saturday and love them - can't wait till November 1st to mount them on. They are 245/45/VR18 rear, and 225/45/VR18 front and fit/look just fine. I would think the 40 and 50 series would be just fine as well, if those are the only one's you can find.

As far as the clicking noise after engine shut-off, I wouldn't worry about that at all. Every car I have ever had sounds different, and it seems to become less and less as the car ages. My M45 is actually fairly quiet after shut-off, yet my A6 sounds like it's making popcorn inside a metal trash can for about 3-5 minutes after I park it and turn off the engine.

Andrew