When I bought my ‘89 GTA back in ‘96, the idler arm, alternator and headlights were already replaced. Everything else (parts wise) except tires, was original.

The car was 7 years old at that point. A few years later, my uncle bought two ‘91 Z28’s (a few years apart) and the same parts were replaced before he bought them. Were these parts prone to failure on our 3rd gens?

Even when looking at used 3rd gens on the used car lots (back in the day), it seems those three things (idler arm, alternator and headlights) were always changed out for some reason.

Why didn’t the original idler arms last that long? Was it due to the modified McPherson front suspension design that added more stress to that particular part?

What about the alternators? Were they just marginal and ready to fail with thei low 105 amp rating and burned out quickly?

How about the original Guide brand headlights? Another part that seemed to be very failure prone on these cars. I’ve had aftermarket Sylvania sealed beam headlights on other vehicles that lasted longer than the 7 years in age my car was back in ‘96.

It’s just strange that those three parts were always replaced unless it was some super low mile original stored in a garage all these years.

Thoughts?

 

Just speculation on my part: but it could be some of these parts came from bad production batches...? But as you suggest, it could also be that GM underdesigned them...

In any case, my experience is the idler arm and headlights on my '89 Formula are still the original equipment, although I'm pretty sure my alternator has been swapped out in the past 15-20 years or so.

 

With Headlights I Think It Depends On How Much Night Time Driving You Do I Still Have 3 Of My Original Headlights And The One That Burned Out Lasted 14 Years

 

Products were produced with poorer parts to save a few $$$ in production costs. Money in GM's bank. Or maybe "built in obsolescence"!

 

The idler arm was probably sloppy from not being greased and wore out. I noticed on my 85 Iroc with 49K miles that both tie rod ends(inner and outer) have been greased but are super sloppy. I'll have to be replacing them. Hoping I can buy bolt sleeve that holds them together as those look pretty rusted together even though this has been in inside storage since 1991. Halogen lights burn out pretty quickly. The Guide OEM bulbs were especially short lived. Alternators might be people putting aftermarket stereo and amps in as the stocks were lucky to be 100 amp output.If they sit, bearings seize or get noisy.