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Should I sell (more likely, trade-in) or should I fix?

Hello Car Talk Community,

I have a bit of a situation… my wife and I have 2 Subarus (2000 Outback & 2002 Forester) with around the same mileage (150K) and are facing the same problem - our catalytic convertors.

I just got off the phone with a trusted muffler shop, and he said that there must be something else wrong. If a cat convertor is going bad, there is something else upstream that is making it do so. It is going to cost about $700 to fix on each car, and I’m struggling with that price tag vs. the value of our cars and the possibility of something else being wrong.

My original idea was to sell (or trade-in) one of them, fix the other, and buy a brand new car (our first!). I’m just worried that I’m going to get nothing from a trade-in, and don’t know if it is ethical to sell a car with possible problems like this. They both NADA for around $3K… will someone buying a car for that price basically accept that they are going to have to fix some stuff in the near future? Or could I sell one for $2K and have a clean conscience?

Thoughts? Ideas? I don’t want to throw away money…

Thanks for your time everyone - hope to get some feedback.

The guy at the muffler shop is correct when he says that something upstream is wrong if your cat converters are both going out at 150k miles. Normally, cats are good for way more miles than that.

What about the maintenance records of these cars?
Have they been maintained at least as well as the mfr specifies? (Please note that while oil changes are very important, there is a LOT more to maintenance than just oil changes.)
Do these vehicles burn a significant amount of oil? (Oil burning can rapidly ruin a cat, but if an engine is burning a lot of oil at 150k, that points toward oil change intervals that were far too long.)

Is the guy at the muffler shop basing his opinion on the need for new cats on merely seeing a stored trouble code? If so, it is very possible that merely an O2 sensor or sensor wiring is at fault.

Assuming the cars otherwise meet your needs and are sound mechanically… trading one in just because of routine maintenence charges is the most efficent way to throw your money away.

I’ve had catalytic converters got bad on two of my vehicles, neither of which were as old as yours. Granted they were covered under warranty, but I’ve read multiple places that you can get a new CC for far less than $700.

It’s not at all surprising to me that 10-12 year old cars need new CC, which is why I consider this routine maintenence. I’d get a second opinion on whether the CC was truly bad, and then shop around for the best price on a replacement. Good luck.

What is the history of oil use between oil changes on these cars? Do you need to add a quart or more every 2000 to 3000 miles between oil changes? Has a compression check and compression leak down tests been done? Subaru’s have a history of head problems (some models and motors more than others, the V6 seems to have the least issues) that could cause more oil to burn off. Also a bad turbo oil seal can put burned oil into the exhaust. At 150K miles your cars could just be showing that they are tired and ready for a rebuild. Best way handle guilt about trading a car with problems known to the seller is to trade it in or donate it for a tax write off.

Any buyer of a used car with 150K miles should expect issues, but a seller should also be honest. A buyer who buys a car with a check engine light on is aware of issues due to the light. If you leave the light on then you are not hiding anything and shouldn’t feel guilty.

Oil use in the Forester is much better than the Outback. The Outback is leaking, showing classic head gasket problems that Subs can have. However, the mechanic that did my water pump/timing belt said that Subarus were just like this, and it could run for another 100K leaking some oil (or not, of course). Whenever I get my oil changed, I make sure to ask beforehand for them to look for coolant in the oil - they have never found any…

The Outback already had its cat replaced around 110K, so it’s only been on there for 40K or so. It has also had its breaks/rotors, battery, alternator, (water pump/timing belt), and radiator replaced in the last 50K.

The maintenance records on both are pretty good - the Outback was maintained at the dealer until I bought it (though, it did sit for a while before I got it - previous owner was saving it for a daughter who ended up moving to a major city). The Forester was a used dealer purchase, and has had Oxygen sensors replaced (under dealer warranty) and has also had the timing belt/water pump change that Subarus require. So, we have been doing our best to maintain them - but the Outback is certainly the one with more obvious trouble.

Ideally, I’d love to sell the Outback for 2K - it has enough amenities (heated seats, 6 disc changer) that a teenager might like it… I don’t think a dealer would give me that for a trade-in.

The Forester doesn’t appear to be leaking anything - still feels pretty good.

And of course I would tell any prospective buyer any known problems… I just don’t know if its worth it to fix them just to TRY to sell it, or if it would generally be expected by someone buying a $2,000 car with 150K that they will have to put some more money into it, since the price is so low.

One more comment - the muffler shop I spoke to hadn’t seen my car - I was calling for a quote and advice. The engine light in the forester threw a cat code, and the knocking sound in my outback was narrowed down to loose items in my cat and muffler by my mechanic. He said I could drive on it, but it was just a matter of time until I needed a new one.

Your problem could be a bad downstream 02 sensor. If the downstream sensor is sending the wrong signal to the ECU it could set a code for a converter inefficiency. The primary operation of the downstream sensor is to verify the converter is doing it’s job. Often 100-150K miles is about the life of an 02 sensor. There are sellers on ebay that sell 02 sensors to fit my car for around $20-$25. instead of the $60-$80 the local auto parts stores sell them for. I bought a new sensor for my '02 Ford Escort about 1 1/2 years ago on ebay for $18. with free shipping. I’d suggest replacing the 02 sensor to rule it out as the possible cause.

Honestly, I’d sell or trace the Outback. If you sell it and the buyer asks, be honest, but if he/she doesn;t ask you are under no ethical or legal obligation to say anything.

As to the Forester, it sound like that one’s still in good shape. I’d repair that one. And IMHO a cat conerter becoming inefficient after 150,000 miles is perfectly reasonable. No exhaust stream is totally cllean of carbon, and it does accumulate over time.

At 10-12 years of age and 150K miles, MOST catalytic converters are at or nearing the end of their useful lives…But I would try Fordman 1959 suggestion first if this is merely a CEL/emissions test problem…If your cars are not required to be emissions tested then there is really nothing wrong with them that’s worth spending $700 on…

In todays market, there is a major shortage of cars in the $3000-$7000 price range. Your cars are sought-after models that will attract eager buyers (I don’t know why, but that’s an entirely different subject) regardless of the “CAT” problem that may or may not even exist…

What leads you to believe the cat converter is actually bad?

Did you just pull a P0420 Catalytic Converter Efficiency Below Threshold code?

Did anyone actually diagnose that the converter is failed? A P0420 on a Subaru means running a variety of diagnosis tests to in fact determine what is going on. It is not an automatic replace the cat converter.

Handy place to educate yourself>> https://www.google.com/search?q=subaru+p0420

good luck

Well, the Forester threw a code - I need to find out which one (my wife went to Advance to have it read) and the Outback actually has pieces loose in it.

Thanks for the link raj, and thank you EVERYONE for your generous advice. It truly has helped. If anybody else would like to weigh in, please feel free. More info the better.