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.

 

The 1980s were a hectic period of time for GM with a significant amount of Corporate Restructuring.
Many of the Divisions and Groups within GM were being merged with new and existing Groups, acquisitions, name changes, and new roles and responsibilities were being made.

AC-Delco was in the process of becoming a large unified Group and had taken over from Divisions like Delco-Remy, the Guide Division, Hughes Electronics, Delco-Packard/ Packard Electric Division, and others.

Unfortunately quality fell through the cracks as all this CHANGE was occurring.

Specifically, the CS130 Model Alternator was a project that suffered from the Delco-Remy Division phase-out/ Merger...
The design is flawed, it over-heats very easily...
And resulted in the Redesign/ Update to the CS130D Alternator, which is an upgrade compared to the Original design.

The Headlamps were cheaply produced knowing that GM was ready to switch to outsourcing Lighting and no longer going to be produced in house.

The Idler Arms unfortunately were not designed around the horrible Front Sub-Frame design of our Cars that has tremendous Flex/ movement.
When the Sub-Frame is reinforced, the Idler Arms are usually fine.
I blame the Chassis Design, not the Idler Arm!

 

My red '88 GTA still has all of these items in their original form, but when I owned the Black Notchback GTA from '98 to '15 I
changed the alternator 4 or 5 times on that car. Was always a trouble spot. I changed the headlights on the same car twice over
that same time span.

 

Imho, the CS130 alternatior is not a bad alternator. It's still an upgrade over the 10/12SI. Admittedly, they did seem to fail every few years, and the reman units back then were often even bigger garbage than today's units. But in my experience in more recent years, a lot of the new CS130 replacements are in it for the long haul.

As for the idler arm, it's a wear item. It has nothing to do with front end design.

The headlights too. It was recommended to replace them every few years because they get dimmer with age.

 

Bought my 1990 in 1992. The alt had already been replaced with a rebuilt unit at that time. It was the spark plug wires that get tossed first back then. Black boring, red cool at the time. BTW - don't know where you store your car, but I'd put a dehumidifier in there, spread plenty of rat poison and also blow fans under the car if you plan on storing it for a while.