And another thing, many short sell factory parts as sub standard.
OEM service parts are usually better quality than you get from the parts store...
If the supplier gets the contract for production parts, and sends more than 2 or 3 bad parts to the car factory, then they have to go through a HUGE HASSLE...
Starting with sending a rep into the plant to sort all of their stock in there. Then get their factory to certify all of the shipments for the next 3 months must be marked that they were sorted and certified to be free of the defect.
Then fill out all kinds of paperwork to root cause how the defect was allowed to be made, and then how it wasn't caught by the check fixtures on the supplier's assembly line inspections. then they have to come up with a temporary and permanent corrective action to make sure that this doesn't happen again...
Now if another of that same defect shows up before their "probation" period ends, then they have to bump it up another level and "double certify" all stock coming into the car plant...
If they keep having problems, and this happens more than 3 times, then their executive management has to meet with the buyer to discuss why they are having so many problems and then told that if this keeps up, then they will not be allowed to bid on any future business - Yeah, hit them in the pocket book... They will loose out on profit for HUNDREDS OF THOUSANDS OF PARTS...
Now the same suppliers also supply the parts for service. Service parts are not scrutinized as much as current production, but are supposed to be built to the same standards. So if a few customers start having problems with the parts and return them, then the company will send their quality team to the supplier to fill out the root cause and corrective action.
If the supplier sends a bad part to a local parts store and we buy it, then return it, BIG DEAL. We are just one sale, not THOUSANDS. So if they know that they have bad parts, where would you send them to???
You got it, send them to the parts stores, as there is not as big of a penalty if you get caught sending them your junk. If you send it to the car manufacturer, it may be shoved up their @ss and then they have to fill out all of the "quality paperwork" which is a punishment all in itself....
So the distributor cap that you buy from the dealer, is probably better quality than the one that you buy from the parts store.
It takes alot more bad parts to be returned from the parts store for the supplier to fix the problem than it does if they send bad parts to the original car manufacturer for service parts....
The company that buys THOUSANDS of parts gets more attention than us guys who only buy one or two parts at a time....