Terribly designed parts?

[pantsman]

Anyone encountered any badly designed parts on their cars that need replacing regularly or lead to difficult/costly repairs?

I'll start with my Ford 5.4L 24valve V8; the list of parts that cause issues in many

Firstly the spark plugs are a two piece design and often break in half upon removal, leaving the ground shield and half the porcelain stuck in the head. Furthermore these two piece spark plugs can break when being installed as well, leading to hard to diagnose random misfires.

Camshaft phasers can die very quickly if they are engaged before the oil is up to temp and leads the two banks of cylinder running 1 or 2 degree's apart

Timing chain tensioners were also an issue from factory and had to be replaced with a new desgin when they failed.

and lastly, but definately not least; the transmission fluid is cooled through a copper pipe that runs through the radiator. Quite often the copper corrodes and leads to atf in your cooling system and coolant in your trans!

[Daffyflyer]

Mid 90s Ford Falcon (Australia), mostly unbreakable and pretty much lasts forever, but for a few things in my experience.

Auto gearbox is poorly cooled and has some shift solenoids that tend to die causing super super harsh shifting.

Coils and Distributors go all the time, like seriously..

Replacing the distributor with a new one will sometimes shear the gears off the aux shaft that drives the distributor, throwing metal shards throughout the engine.

Headgaskets are crap, there is a great MLS replacement that fixes all of the issues, but until you do that you're going to blow a headgasket, almost guaranteed.

Brake discs wear and warp at an unusually fast rate, even under very light use.


All these things are from experience.. *sigh*

[Slim Jim]

My old T-Bird Turbo = the A4LD transmission was very weak and failed. A rebuild, even with a new torque converter, it still didn't last - had to baby it, but the head gasket went before the transmission went so... LOL

My old Taurus SHO = rod bearings didn't last as long as they should, but I sold the car before I replaced them. Parking brake kept sticking too.

Both Lincolns = fuel level sending unit has a mind of its own. Neon taillight ballast commonly fails but lasts pretty long all things considered. Under tank emissions tray (EVAP tray) ALWAYS rusts out (and yet everything else underneath is OK?). Cupholders look pretty, but aren't particularly functional when they're not broken -- and if used extensively over time, they WILL break (very weak plastic). I second the warped rotor complaint on both Marks. Oh, and the 1-2 accumulator piston in the transmission (more of a problem on the silver car since it's a stock transmission - green car has a built tranny).

[adamd]

Headgaskets are crap, there is a great MLS replacement that fixes all of the issues, but until you do that you're going to blow a headgasket, almost guaranteed.

The same can be said for the Rover K series. A fantastic engine let down by cost cutting, leading to a poor cooling design and headgasket issues. The problem was only properly rectified after Rover was already gone.

The Toyota ZZ engine. Fitted to a massive amount of Toyotas, those between 1998-2003 commonly develop serious oil burning issues relatively early in their life. For example, our 2001 Avensis needed a new engine at 83k miles (fully serviced, so fortunately provided free by Toyota).

My current Prius has a common issue with the stereo, where when the car has been in warm weather all the buttons on the front panel stop responding.
(I'm really not doing Toyota much of a favour here, I love them really. )

A friend's Citroen had what has to be one of the strangest design failings though. The C3 is known for a common issue where the windscreen washer tubes under the bonnet leak onto the injectors. He has a C3 Picasso, which managed to take this problem even further. The water leaks onto the end of an exposed wire, and over time through some sort of capillary action makes it's way down the wires, corroding them as it goes, until eventually it reaches the main fusebox. Once there it corrodes all the contacts, meaning the fusebox and wiring loom must be replaced. After it occured, he found it happened to many other owners when looking online.

As a side note there, the PSA 1.6 diesel that powers that car is notorious for turbo failure and injector seal failure due to poor design.

[pantsman]

Mid 90s Ford Falcon (Australia), mostly unbreakable and pretty much lasts forever, but for a few things in my experience.

Auto gearbox is poorly cooled and has some shift solenoids that tend to die causing super super harsh shifting.

Coils and Distributors go all the time, like seriously..

Replacing the distributor with a new one will sometimes shear the gears off the aux shaft that drives the distributor, throwing metal shards throughout the engine.

Headgaskets are crap, there is a great MLS replacement that fixes all of the issues, but until you do that you're going to blow a headgasket, almost guaranteed.

Brake discs wear and warp at an unusually fast rate, even under very light use.


All these things are from experience.. *sigh*

I have the same old Ford Slushbox attached to my 5.4 lol! I've seen and worked on about 50 Ford straight sixes, every single one had a leaky head gasket. I've changed the coils on about 10 E series falcon too.