1990 HONDA NSX NA1

Typical onset: every 60,000-90,000 mi or 6-7 years

Symptoms: catastrophic engine damage if belt snaps, water pump bearing noise, coolant weeping from pump, belt cracking visible on inspection

Fix: This is interference engine territory—snap the belt and you're looking at bent valves minimum, full engine rebuild worst case. Service interval is 90k/6yr but most techs say do it at 60k on these. Labor is 6-8 hours because of mid-engine layout and need to remove engine cover, plus replace tensioner, water pump, and all accessory belts simultaneously. Use OEM Honda belt or risk your investment.

Estimated cost: $2,000-3,500

Typical onset: any mileage on affected VINs

Symptoms: grinding on deceleration in 2nd-5th gears, popping out of gear under load, metal shavings in transmission fluid, complete loss of gears

Fix: Early NA1 manual transmissions (roughly VINs MT000001-MT002300) had improperly heat-treated snap rings that fracture. The countershaft breaks loose, chews gears, game over. 1990 models are typically safe but verify VIN. Fix requires transmission removal (8-10 hours) and internal rebuild with upgraded snap ring and likely new gears/bearings. Some owners proactively replace snap ring around $2k; waiting for failure adds another $3-5k in hard parts.

Estimated cost: $4,000-9,000

Typical onset: 80,000-150,000 mi

Symptoms: metallic ticking from valve covers at idle, ticking increases with RPM, loss of VTEC crossover smoothness, Check Engine Light for cylinder misfire

Fix: C30A engines develop noisy hydraulic lifters, especially if oil changes were stretched. Starts as nuisance noise, progresses to worn cam lobes and rocker arms. Proper fix is pull both heads (12-16 hours labor), replace all 24 lifters, inspect/resurface cams, new gaskets and seals. Some try lifter replacement in-chassis but access is nightmare. Oil starvation in VTEC circuit can wipe cam lobes—seen it twice on track cars. Use 10W-30 Honda synthetic and 3k-4k mile intervals to prevent.

Estimated cost: $4,500-7,500

Typical onset: any mileage, age-related

Symptoms: transmission fluid puddles under engine bay, low fluid level on dipstick, burnt smell after driving, slipping between gears

Fix: Rubber cooler lines and steel hard lines corrode or crack after 25+ years. Leaks often start at crimp fittings or where lines pass through chassis. Replacement requires removal of undertray and sometimes rear subframe access (4-6 hours). OEM lines are discontinued for some fittings—expect custom fabrication. Running low on MTF will kill synchros fast; repair immediately.

Estimated cost: $800-1,800

Typical onset: 100,000+ mi or age-related

Symptoms: windows move slowly or stop mid-travel, clicking from door but no movement, master switch buttons intermittent, window drops into door

Fix: Power window regulators use plastic sliders that crack, and master switch contacts corrode. Window motor itself usually fine. Door panel removal and regulator replacement runs 2-3 hours per side. OEM regulators are $600+ and NLA for some years—aftermarket quality is hit-or-miss. Master switch can sometimes be disassembled and cleaned, but replacement is $400-700. Not a safety issue but annoying on a $90k exotic.

Estimated cost: $600-1,400

Typical onset: any mileage, age-related

Symptoms: blend door clicking or grinding, stuck on hot or cold only, blower only works on high speed, no airflow from vents

Fix: HVAC servos (control airflow doors) fail due to dried grease on plastic gears. Blower resistor pack burns out from age. Servo replacement requires full dash removal (10-14 hours) unless you attempt cowl-access shortcut. Resistor is 1-hour job behind glove box. Some owners live with manual servo override via cable. Parts are $150-400 but labor kills you on servo work.

Estimated cost: $400-2,800

Typical onset: any mileage, heat-cycle related

Symptoms: engine cranks but won't start when hot, starts fine when cold, intermittent no-start, fuel pump doesn't prime

Fix: Classic Honda issue: main relay under dash has cold solder joints that crack from heat cycling. Engine cranks forever, no fuel pump prime. Relay is $80 and 30 minutes to replace, or pull it and resolder yourself in 15 minutes. Strands people but easy fix. Keep spare relay in glovebox if you daily-drive this.

Estimated cost: $100-250

Typical onset: any mileage, age-related

Symptoms: coolant smell after driving, visible green stains on hoses, expansion tank shows stress cracks, overheating after spirited driving

Fix: All rubber coolant hoses are 30+ years old and go brittle. Expansion tank plastic cracks at mounting tabs. Hose failure dumps coolant on exhaust = fire risk. Full coolant system refresh (all hoses, clamps, tank, thermostat) is 6-8 hours due to mid-engine access. Do it proactively with timing belt service. OEM hoses are $600-900, aftermarket silicone kits run $400 but quality varies.

Estimated cost: $1,200-2,200