Hey everyone. I have a 2003 350Z and owned it since 2018. Driven from 166k to 177k miles.
To those with long term ownership, at what mileage did things start to go out and need replacement? I'm thinking relays, alternators, starters, fuel pump, timing chain stuff, etc.
Just want to plan ahead so I don't get stuck on the side of the road.
Here's what I have done so far:
Radiator
Radiator Fan
Thermostat
Several misc coolant hoses
Aluminum coolant bleeder
All fluids
Ign Coils
Spark Plugs
Valve cover gaskets
Brake hoses
Brake MC
Flywheel
Clutch
Anything else I should plan for?
Thanks!

 

Good on you for tackling the most important items so far (I would've stuck with OEM coils though). I'm impressed that your Z made it to nearly 200k mi up in Wisconsin, I'm guessing you have it stored for the winter months or was this an out of state purchase?

I would recommend struts and bushings (sway bars, control arms, rear diff, trans mount, engine mounts). Wheel bearings are another wear item. Usually the rears start acting up even before the mi mark you've hit. The other items you listed are good to be aware of, but most are easy enough to tackle when a fault occurs (starter, relays, fuel pump, alternator). What I mean is, you won't suffer catastrophic damage if one of these components fail, but it would still be an inconvenience. The exception would be the timing chain set. It's a good idea to get this replaced around 150k mi, but chains are more robust vs. belts and the wear on them is more dependent on how often oil change services are done vs. mileage. Also, if you haven't already done so, I would replace your accessory belts if they show any signs of cracks/fractures. It's possible your Z is already on it's 2nd or 3rd set. If you tackle the timing chain, it's best do to the water pump at the same time. There's a weep hole for the water pump next to the AC compressor. If you see any green or blue crusties around there, most likely the pump seals are beginning to fail.

Things to be prepared for...the entire AC system. Compressor, expansion valve, evap. core, and AC condenser/dryer. ACs go out on pretty much every car as they age. Usually it's the expansion valve, compressor clutch failing, or the condenser getting a pin hole leak. If you rely on your AC in the summer, be prepared to replace it when it starts acting up. I would also be prepared to upgrade/replace the 6MT in your 03. The early 6MTs are known to have syncro issues. When you replaced the clutch did you upgrade the clutch fork and pivot ball assembly to the cast iron unit or are you still using the stamped steel fork with elongated pivot ball? How about the clutch hydraulics? Did you replace the CMC and/or CSC? Also, how's your power steering rack and pump holding up? Most will slowly weep a little, but it shouldn't be dripping wet. Keep an eye on your CV axles to. The rubber bellows tend to fail/crack and leak out the grease around this mileage point.

I think that about covers all that I can think of. Most of these items you can easily diagnose at home. Just be vigilant, pay attention to any fluid drips/leaks, inspect underneath your car during oil changes if you do your own services.
Cheers!
-Icer

 

thank you shitty forum. can I have my 10 minutes back now?
not speaking about the content here which is excellent. speaking about the 20-year-old software.
well hell, I can't remember everything I just wrote damn it.
The last item was the VLSD in your rear differential so that's all I will bother mentioning here. it's probably toast with that many miles. you can get a replacement from a wrecking yard. some G35 models had better ratios. a Z1 rebuild is $3,000 but a torsen gear would be really sweet.

 

Oh yes forgot I did the fork, pivot upgrade, and clutch line when I replaced the clutch. I did front wheel bearings but not rear. Might go with the 370 rear upgrade when the time comes.

Still on OEM suspension and surprisingly still holding up pretty good. Took her to Road America recently and did not have any issues. OEM height and feel is perfect for me. Not sure what to replace it with in the future. Wonder if Bilstein shocks and oem springs would be good enough?

What are guys doing for a LSD upgrade, I haven't done any searches, I wonder if there is an easy upgrade from Mfactory, Quafie, etc...

My 03 transmission also goes into all gears with little issues. 5th gear does grind about once a month.

Anyone else have starter, alternator, fuel pump fail at a certain mileage? Might just do these to avoid the inconvenience.