Where is the honeycomb?
 

Upon replacing the front catalytic converter on an '04, 2.4L, I noticed that the honeycomb is completely gone. I'm the original owner and nobody has tampered with it prior. Therefore I can only assume that it broke into smaller pieces and moved further downstream. But where?

Does anyone have a guess as to where in the exhaust system these pieces might have ended up and what are the chances that they're blocking the airflow?

If you are losing antifreeze out the cylinders, or put too much injector cleaner in the gas, or if you burn leaded gas, then the CAT dissolved from one of those. CATs don't dissolve unless there's a reason.

As far as I can tell, the antifreeze level has always been fine - I've rarely, if ever had to add any. I've NEVER used injector cleaner and NEVER burned leaded gas. While those are all interesting to note, what similar things could be the cause?

Let me offer that I have had to put in a quart of oil a month on average and the vehicle averages 1,750 miles a month.

Sounds like a lot of oil usage, like you burned that motor up pretty good.

Yes, that motor is way undersized for the size vehicle. I should have gotten the 6 cylinder.

More likely you foot is made of lead, and you beat the snot out of it, didn't do the maintainence, and turned it into junk. Drive slower with the next car, take care of it better. Sorry, don't mean to be flippant, but it's the truth. You'll probably live longer and won't have to buy so many cars.

My wife is the primary driver of the vehicle and accounts for 98% of the mileage. She's about as easy on the car as anyone could be, except Grandma. As for maintenance, I've kept up very well with it, as the Maintenance Log will attest to.

Perhaps the hilly topography where we primarily drive it has something to do with the premature wear. Let's face it, the car is a fairly heavy SUV. It should be capable of carrying a family of 4 with gear. Yet ever since it was new, we'd have to turn off the AC while driving up hills just to maintain a decent speed.

The little 4-banger just works too hard to move this car around. That's the plain and simple truth. Unless you have one yourself, and have driven under similar conditions, you may not fully realize it.

My apologies, you're right. Hilly terrain probably is the key factor here. I used to live on a mountain, and can attest to the fact that mountains kill motors. The 2.4 L motor develops 150 hp, but there's no torque. I had a Sonata with that motor, but I lived in a flat place back then, and I had a five speed trans.

Apology accepted.

I failed to mention that my other car has 368,000 miles and utilizes a 1.6 liter 4 cylinder engine that drives a 1.5 ton vehicle. Obviously, it's not the original engine. Nonetheless, I believe that it demonstrates my ability to take proper care of a car.

Where to go from here
 

I'm not in a position to buy a new car at this time. Aside from the engine issue(s), the Santa Fe is just fine and we like it (similar to our Elantra). I am capable of just about any mechanical feat. So I'm trying to determine best options. For example, I could rebuild the existing 2.4 engine. Or, I could get a low mileage 2.4 or 2.7 from the bone yard.

Which would be the best way to go? I already replaced the timing belt and water pump on the existing engine. So if a one-to-one (2.4L) swap were done, I could just move those over. But then I'd still have the issue of an underpowered engine for the terrain that we're travelling.

What about the 2.7? Would anything else have to be modified to accept it (e.g transmission, mounts, exhaust, etc.)?