And why would you check inside the carbies if the car was only in to get some rust cut out and metal welded in? I'm sure its something most people wouldn't even think to do before driving it home. When I got my Skyline back from the panel beaters after fixing some damage from someone running a red light and hitting me, I didn't examine the engine at all. I just trusted that they had done their job correctly, and replaced all the damaged parts, and I haven't had a problem with it since. It all looked fine. I wasn't going to start pulling air cleaners apart to check for metal dust. It not something that you would expect to have to do. If you take you car for service, do you check the oil and water before driving it home? do you open up the air cleaner to see if they put a new one in there? do you open the timing belt cover to make sure its a new belt? If you get new tyres, do you whip out an air pressure gauge and measure the air pressure? take a torque wrench to the wheel nuts? Who do you trust these days? They sound dodgey though. They should have covered the engine to prevent that sort of thing happening. If you have an angle grinder shooting sparks at those foam ramflo air filters, I reckon it wouldn't take long to burn a hole through them I don't think it costs much to start a small claims case against them. If not for the engine problems, as that would be hard to prove with no photo evidence, then for the dent they put in you car. If you cant be bothered with legal action, or filing a complaint with whatever association they are a member of, or a government department (consumer affairs or whatever), then a campaign of negative publicity should be your revenge. Just tell everyone who asks about your car how they ruined your engine. I had to file a complaint with consumer affairs once, against a car dealer to get the rear shocks replaced on a car I had just bought, after they refused to do so, and stopped answering my phone calls. The shocks were the mega expensive height adjustable ones for a mazda/laser tx3/323 turbo that cost about $700 each I think. They replaced them - they had no choice after they were ordered to.