So, this is a bit more specific than the title, but namely I have a 2008 Scion tC. I bought it used and it came with an aftermarket K&N CAI and an aftermarket exhaust.

Now for those unaware, Toyota underwent a class action lawsuit in 2014 over oil consumption in the 2AZ-FE engines. Essentially, they're required to perform tests on anyone with that engine who requests one and has under 150,000 miles.

I'm going to go in to get my test done soon, which it will pass (or fail, depending upon how you look at it) with flying colors (I use about 1.5 quarts every 1000 miles), and I'm just trying to make sure there's no way they can deny me the service.

I understand simply having the parts on doesn't void it, but could they possibly claim that the CAI is the cause of the increased oil consumption? If so, I'll simply buy a stock airbox, the alternative being sacrificing a $4000 engine rebuild.


  • 2
    They will probably give you trouble to intimidate you into paying for the repair, but they have the burden to prove that your modified part caused an issue. I believe this question is better suited for Law.SE as it has to do with Warranty more than Mechanic.
    – Yousend
    Commented Dec 16, 2016 at 16:53
  • 3
    Either way, I'd go to a junkyard or check your local craigslist and swap the OE intake back in before you head in. Commented Dec 16, 2016 at 17:28

2 Answers 2


Assuming you're in the US:

According to the Magnuson-Moss Warranty Act: In order to deny warranty coverage because of a modification to the car, they must prove that the modification is the cause of - or, at the very least, related to - the damaged component.

For example: If you have a suspension problem and have a cold-air intake, they can't void your warranty. However, if you installed a supercharger and experienced ring or bearing failure, they are most likely justified in voiding the warranty.

It's a pretty big stretch to say that the intake had anything to do with oil consumption, especially since this is a known issue with your model.

I'm not a lawyer, but I believe the law is on your side here. If the dealer tries to deny your claim, speak to Toyota customer service - corporate, NOT the dealership - and they will probably help you out. If that doesn't go anywhere, talk to a lawyer. This is pretty cut-and-dry.

Of course, the EASIEST way to get around this is just to buy a stock airbox, as you said. There are many cheap ones out there from wrecked cars, or people that have modified their car and have the stock parts just taking up garage space.


Did you buy this car from the dealership that you're approaching about the engine replacement? If so, and they said that the car was under warranty knowing that it had the CAI, I don't see how they'd be justified in denying the claim.

Edit 2

Funny thing: Magnuson-Moss contains a provision for providing free legal help for the consumer.

  • 1
    Bought it from some third party dealership. And this is basically my thinking is that, while I probably am fine, it might be easier to eat $50 or so and not risk it. I'd rather just get my new engine and be on my way (plus I get to have a newer loaner to drive during the winter). Commented Dec 17, 2016 at 5:10

Well, 2 things:

  • whether your CAI has anything to do with the oil consumption and whether the law is on your side is besides the point. The law is based on "reasonable" answers, not "correct" answers, and if you take them to court the burden of proof will be on you to prove that your CAI did NOT damage your engine, and you can't. You have a CAI and an oil consumption problem, you can't prove to a mechanical layman (which is what a judge is) that they're not related.
  • best advice: go to a junkyard, grab an airbox and swap it out only for the test. People in areas where vehicles need to be smog-tested every 1 or 2 years do this with their intake and exhaust mods.
  • The burden of proof in civil court is a preponderance of the evidence. He doesn't have to "prove they're not related", he has to show that's it's more likely to be caused by the known, existing issue -- which seems quite easy. Though I agree that swapping out the part would be best. Commented Dec 16, 2016 at 22:20

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .