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!