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Question about a catalytic converter for a 94 6cylinder 3.9 van

09-11-2007, 06:39 PM
A year ago this past July I needed a new catalytic converter put on my van. I took it to midas at the time they placed a universal converter on it. This past June I had a short in my wiring harness dealing with the o2 sensor. My van is a 3.9 v6. My mechanic who is AAAs certified mentioned to me that who ever placed the converter on my van had put one on for a four cylinder engine and that it was one placing back pressure on my engine and also lowering gas mileage.
I took it back to Midas and they placed it up on the rack and the manager came out looked at it and told me that this converter was a universal one and would fit any car on the road. Can anyone tell me who's right and who's wrong as to the correct cataylitic Converter? Thanks.

09-11-2007, 07:55 PM
It's called universal for a reason. It's all based on the size of the inlet and outlet pipes. If your vehicle has 2" pipes, then a 2" universal cat is what goes on. Your mechanic is likely being fooled by the overall smaller size of the universal cat versus the direct fit one. As long as the pipe size matches the original one there will be no increased back pressure. A smaller cat just means a shorter lifespan. But hey, that's why they cost 1/4 of what the direct fits cost...right?

09-11-2007, 08:29 PM
Thanks alloro for the info. Actually the pipe size originally is larger than what the new cats size is. The cat pipe probably is 2' but mine is slightly larger...They adapted it to

09-12-2007, 09:49 AM
If they had to reduce the diameter then they used the wrong cat.

09-13-2007, 08:12 PM
Thanks for your reply alloro-I guess a I need a second opion from one other other mechanic then I can go after Midas for negligence. Its a corporation run by incompetent people who have quotas to fill...

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