Hello, This is my first post. I am a one owner 350Z. I bought it new in 2002, it’s a 2003 enthusiast model, and just turned 231k miles on my
car. It runs like the day I bought it. It’s bone stock, with exception to the window tint and a stereo upgrade. I have kept up with the maintenance and I drive it every chance I get. Eventually, I’m going to need to break the engine down to parade rest and I wanted to get your thoughts as to whether a rebuild is where I should go or if I should replace the entire engine. I don’t race, or pretend to but I do enjoy driving my car. I appreciate your thoughts and suggestions.

 

Welcome and congrats on keeping your Z in good shape. Before you start tearing down anything, I'd suggest you do a leakdown and compression test to get a read on the overall health of your VQ. How many clutches have you put in?

 

Congrats on the awesome mileage! What all have you had replace/repair with that many miles?

 

It's a post like this that gives me hope that I can hang on to my Z for many more years/miles with regular maintenance! Mine's a 2005, 2nd owner, with 134k miles on it now (I purchased it with just uner 125k miles 3 years ago). The engine is still stock, as well, and I have the manual transmission and am still on the original clutch. At the rate I am putting on miles (it is a warm-weather-only vehicle for me here in MI), it may be around 15 years before I reach the miles you're at now

 

It’s an automatic, I haven’t had to do any major work other than it’s general scheduled maintenance.

 

I replaced the original serpentine belt at 200k miles as it was showing some cracking. I’ve changed out the Throttle position sensors a few times, maybe every other year since it was new. Aside from that, it’s been a strict maintenance schedule and Ive used only Mobile-1 synthetic oil and premium fuel, trying to use non ethanol fuel when and where I can get it.

 

I don't think you should replace the engine or rebuild it honestly. If it's been nothing but reliable just keep driving and doing maintenance and fix things as they come along. That being said, you definitely want to check for any signs of wear on the timing components with that much mileage.