First, the most common rumor out there is that if you put any kind of performance part on your car, that your warranty is voided.
This is not true because it would mean that no warranty claim of any kind would be honored.
Putting a performance part, or any aftermarket part for that matter, just means that any failure related to or caused by that part would not be covered entirely, or at all, by your warranty. However, a failure not related to that part will still be covered.
This is because of the Magnusson-Moss Act. Basically, a warranty can not be denied just because you put aftermarket or performance parts on your car.
Great, so I can put any part on my car that I want to, and they can’t deny my warranty, right?
Well, no. The manufacturer can deny a warranty claim if they can prove that it was caused by the aftermarket part. And the thing that you have to keep in mind is that they have all the engineers that designed the car working for them so they have a pretty good idea what putting on this part or that will do.
So basically, unless you have a team of engineers on your side, you probably don’t want to rely on this. What this means is that there is a chance that a failure will still be at least partially covered, or it might not. What I can tell you from my experience is that the further you push the car beyond its designed limits, the less likely that a warranty claim will be honored.
Unfortunately there aren’t any hard fast rules as to what you can do, and what you can’t, and usually each failure is looked at on a case by case basis.
Okay, so what does that mean to you?
Well, first and foremost, it means that you have to understand what you are doing with your car. It is great if you can get your car to make 100 wheel horse power over stock, but if that additional power causes the transmission to fail, most likely it won’t be covered by warranty. As long as you understand this and understand the possibilities of what might happen, then this shouldn’t really be a problem.
This is where it can help to have a good shop that can answer your questions and give you an idea of what might fail if you push past a certain point, or to let you to know the safest way to reach your performance goal, etc.
Another thing to keep in mind, especially if you work on your own car, is that if you do have an issue, you need to bring your car into a dealership so that they can have a technician look at your car. Most manufacturers will not honor warranty claims from an independent shop. Also, if you do take your car to an independent shop, and they start working on your car, this can sometimes cause a claim to be voided. If they remove and disassemble a part, the dealer’s technician is not able to evaluate the part on the car, which usually causes a claim not to be honored.
In other words, if you think that your engine failed, and you take your car to an independent shop and the pull it, you may still have a chance of the failure being covered under warranty. However, if the shop disassembles the motor, more than likely a claim would not be honored at that point. The reason for this is that a technician needs to see the parts in their original context.
So does this mean that you can’t take your car to an independent shop to get it worked on? Not at all. However, if you think that you have an issue that would be covered under warranty, you need to take your car to a dealership first.
This is definitely not an easy issue, and if you still have questions after reading this, post them as a comment and I will do my best to answer them.