Coffee and Z's

After months of struts, fluids, tires, and an oil change, I figured it was time to stop wrenching and start enjoying. So I took the 300ZX convertible out to Nashville Cars and Coffee to see how she'd do in mixed company.

This car has lived a pretty sheltered life at just under 39k miles, and honestly most of its recent miles have been test drives up and down my street after finishing a job. Getting out on the highway and into a crowd of fellow enthusiasts felt like a proper debut.

The drive out was smooth - the KYB struts and new Falkens made a world of difference compared to the 32-year-old originals. That's my wife posing with the Z - she's been patient through all the garage time, so it was nice to finally have something to show for it.

The turnout was great despite the overcast skies, and the 300ZX drew its share of attention. It's not every day you see a Z32 convertible in the wild - Nissan didn't make many of them. A few folks stopped to chat and couldn't believe the mileage. I get it. I still can't believe it either.

Not a bad reward for a winter's worth of garage time.

300ZX Oil Change - Restore & Protect

With the full suspension refresh wrapped up and fresh fluids throughout the drivetrain, the 300ZX convertible was overdue for an oil change. The factory fill was long gone from the other services, but I hadn't done a proper oil and filter change yet, so it was time.

I decided to switch things up this time and go with Valvoline Restore & Protect Full Synthetic 5W-30 instead of my usual Mobil 1. Valvoline's Restore & Protect line is formulated for higher-mileage and older engines - figured it was a good fit for a 33-year-old VG30DE with only 39k on the clock. Low miles, but age takes its toll on seals and gaskets. This Z also has a bit of lifter noise - something the VG30DE is known for - and I'm hoping the Restore & Protect can help keep those tiny hydraulic lifter orifices clear.

I paired it with a Nissan OEM oil filter (15208-65Y0A) - no reason to get creative with the filter when the factory part is still readily available. Drained the old oil, swapped the filter, and filled her back up. Simple and clean.

Odometer sitting at 39,020. She's not racking up the miles, but she's getting the attention she deserves.

Fresh Legs for the Z32

The reason for the 300ZX visiting my garage was leaking rear struts. Not surprising - they're the factory originals with 32 years on them. Only 38,900 miles, but time doesn't care about mileage. I decided it was time for a full suspension refresh with KYB struts all around.

I started with the rears in early November. Getting the strut assemblies out of a Z32 is a bit of a wrestling match - the suspension arms don't exactly drop down on their own. My solution was a ratchet strap to pull the arms down far enough to clear the strut for removal and reinstall. Worked like a charm.

One thing I noticed during disassembly was that the factory rubber strut mounting gaskets were completely shot. The OEM replacements are absurdly expensive, so I designed a set of gaskets and printed them in TPU. The flexibility of TPU makes it a great substitute for rubber - it'll handle the vibration dampening while lasting a lot longer than the originals did.

I came back to the fronts in late December. Same process - old struts out, new KYB assemblies built up with the printed gaskets, and installed.

The difference is immediately noticeable. The car feels planted and composed in a way it just wasn't before. Thirty-two years of slow deterioration means you don't really notice how bad things have gotten until you put fresh components in. The Z32 is riding like it should again.

I'll Take Transmission Fluid Over Eggnog

With the 300ZX convertible getting a full refresh this fall and winter, the transmission and differential were next on the list. Both still had their factory-original fluid from 1993 - 32 years in service. Christmas Eve seemed like as good a time as any to change that.

I started with the transmission. The drain plug is magnetic, and after pulling it the fluid came out looking about how you'd expect for three decades of service - dark, but not terrible.

The magnet on the plug looked normal - no concerning metal or shavings. That's a good sign for a transmission with only 38,900 miles on it. I refilled with Motul MT-90.

Next up was the rear differential. Same story - original fluid, same vintage. I drained it and refilled with Red Line 75W-90 GL-5+ Full Synthetic. I didn't grab any pictures of the diff work, but the process was straightforward.

Between the coolant flush, clutch fluid bleed, and now the transmission and diff, all the factory fluids in the drivetrain have been replaced. The only original fluid left in this car is probably whatever's still hiding in the power steering system. One less thing to worry about heading into the new year.

New Rubber for the 300ZX

The 300ZX was rolling on tires that were well past their expiration date - over 20 years old, and the sidewalls showed it. Dry rot and cracking all the way around. At that point it doesn't matter what the tread looks like; age is the killer and these were long overdue for retirement.

I ordered a set of Falken ZIEX ZE950 A/S Ultra High Performance All-Season tires in 225/50R16 from Tire Rack - my go-to for tires. They showed up quickly as usual. Once they arrived I mounted them myself, putting the tire changer to good use again. That machine keeps paying for itself.

The Falkens are a solid fit for the ZX - the Z32 isn't a dedicated track car, so an ultra high performance all-season makes more sense here than a sticky summer tire, especially at this mileage. Fresh rubber makes a noticeable difference on a car that's spent so long on cracked and hardened tires.

Pass the bottle!

The 300ZX has been getting a full fluids overhaul, and the clutch hydraulic system was next in line. I've been working through every reservoir on this car - most of it still running factory-original fluid after 32 years - and the clutch master cylinder was no exception. A look through the reservoir told the story pretty quickly.

I popped the cap to confirm what I suspected. The fluid was dark brown and well past its service life.

With the car on the lift, I got eyes on the slave cylinder for the first time. The NABCO unit is heavily surface-rusted on the outside - not surprising for a 32-year-old car - but the bleeder screw was intact and cooperative.

I attached a bleeder bottle to the slave cylinder and flushed the system from the master cylinder down. Fresh DOT fluid all the way through.

The clutch pedal feel is noticeably better. Hard to argue with fresh fluid after three decades.

Keeping Cool After 32 Years

The 300ZX convertible has been sitting pretty much untouched since 1993 - and that includes the coolant. With 32 years of factory fill in the system, I figured it was time to flush it out and start fresh.

I grabbed some Prestone cooling system cleaner, a few jugs of distilled water, and some concentrated antifreeze. The plan was to drain what I could from the radiator, flush with the cleaner, rinse with distilled water until it ran clear, and refill.

With the car up on the lift, I pulled the radiator drain and let the old coolant flow. I left the block drain plugs alone - they're nearly impossible to reach on the VG30, and I wasn't about to risk snapping a 32-year-old plug. Turns out I didn't need to worry anyway - for being 32 years old, the fluid actually still looked pretty decent. No visible corrosion, no gunk, no discoloration beyond the usual green. Nissan knew what they were doing with the factory fill on these.

After the flush and several rinse cycles with distilled water, I ended up draining about five gallons of old coolant and rinse water combined.

For the refill, I calculated the amount of concentrated antifreeze I needed by taking the total coolant capacity from the FSM and subtracting what I drained on the last flush. That gave me the volume still trapped in the block and heater core, so I could mix accordingly and hit the right ratio. Topped off the overflow reservoir and the system took the new coolant without any drama.

One more factory original fluid crossed off the list!

Clipping Along

The parcel shelf on the 300ZX convertible is held in place by two large retaining clips. These aren't your standard off-the-shelf size, and after 32 years the OEM plastic had become brittle and cracked. The shelf itself wasn't going anywhere without them, but the two empty holes where the clips should be weren't exactly a good look.

I designed a replacement clip in CAD and printed a set in ABS. ABS was the right call here - these clips sit right behind the rear glass and will see plenty of heat on a sunny day. The design follows the OEM geometry with slightly thicker walls for durability, but since I was already going through the trouble of designing them from scratch, I figured I'd add a little flair and embossed a Z logo on the face. Why not?

The clips snapped right into the shelf and look great. No more empty holes, and a subtle Z badge that only the observant will notice. Another small win for the 3D printer.

A Family Visit

Every now and then a family member comes to stay for a while. In this case, it's my dad's 1993 300ZX Convertible - one of the rarer Z32 variants Nissan built. With just under 39,000 original miles on it, this car has been well preserved, but time catches up with everything. Factory original fluids, factory original struts, factory original tires - you get the idea. Thirty-two years of "original" adds up.

The plan is an extended stay here in the garage to knock out the maintenance backlog. Struts, coolant flush, clutch hydraulics, transmission and differential fluids, new tires - basically everything that ages out regardless of mileage. The car doesn't get driven much, but that's almost worse for some of this stuff. Rubber deteriorates, fluids break down, and struts lose their damping whether you put miles on them or not.

I got her up on the lift and took a good look around. For a 32-year-old convertible, the condition is impressive. No rust, solid undercarriage, and the VG30DE looks like it's barely been touched. It's going to be a fun project working through the list.

Stay tuned for more!

Pan Handling

At just under 2,700 miles, the Z was due for its second oil change. I captured an oil sample at drain for SPEEDiagnostix analysis - my second sample on this engine - and figured this was the perfect time to swap the stock oil pan for the Z1 Motorsports aluminum pan I'd been eyeing.

The stock pan is plastic. I'd already installed a Z1 aluminum undershroud to protect it, but the Z1 aluminum pan appealed to me for a few reasons. Over time and heat cycles, that plastic pan will become brittle. The Z1 pan also increases the oil capacity - never a bad thing. But more importantly, the design of the stock pan leaves about 8/10 of a quart of dirty oil trapped in the bottom. The metal insert for the drain plug has to be reinforced in the factory plastic pan, and that reinforcement creates a pocket that never fully drains. You can see it in the photos of the factory pan.

With the stock pan off, I got a good look at the VR30's internals - oil pickup, timing chain, and the inside of the block. Everything looked clean and healthy for a motor still in break-in. No unusual deposits or wear marks. Good signs.

I cleaned the mating surfaces, applied the new gasket, and torqued the Z1 pan into place. The fit was spot-on. With the added capacity of the Z1 pan, it took over 6 quarts to fill - a nice bump over stock. Swapped in the fresh filter and buttoned everything up.

The difference underneath is night and day - that finned aluminum pan sitting next to the red front subframe looks like it belongs on a purpose-built machine. Form and function in one shot.