2010 Prius II 155k - what to watch for or unload now?

yes, i think that is a decent gamble

 

In my opinion, the best way to determine the state of the EGR system is to pull it out and clean it. That way you can determine how much carbon deposits were in the system, and how freely the valve was to operate. It sounds like it's overdue for that anyway. I'd also pull out the intake manifold and clean the passages there and replace the PCV valve while you're at it. That only adds a couple gaskets and a $10 PCV valve to the project.

Since you live in the Rust Belt, maybe a better way is to see how badly the suspension is rotted out. Out here, I've gotten over 200K with the brakes on my old Gen 2, and they were still going strong.

I don't know how much the tax code has changed, you may have missed out on it but I bought a used Gen 4 Prime and got $4K back on my taxes. That was before 45/47 got back in office though.

 

Yeah it's virtually one of the rites of gen 3 ownership, to DIY the EGR cleaning. It's involved for sure, but not over the top. In addition to the top two links in my signature, here's a rough workflow:

Professional EGR Cleaning Resources | Page 9 | PriusChat

Doing it yourself, the most it's really necessary to spend would be a new EGR valve, if the existing has a groove worn in the "ski jump". (inside a little inverted bucket inside the valve). Other than that, everything is cleanable. You're looking at around $30 for replacement gaskets on the intake manifold, just the pliable ones, the metal gaskets are much more durable. Plus rags, brake cleaner, caustic solutions for the EGR cooler.

Don't get complacent, thinking a long overdue EGR cleaning will prevent head gasket failure. I'd be prepping for that eventuality as well.

 

I think it might be useful for you to understand that not everyone agrees that cleaning the EGR is that much of a necessity. Personally I look at it as an interesting theory, but I've never seen any real data to support it.

It's a moot point to me because our car has a different engine with a different EGR system and isn't known to clog its cooler OR breach its head gaskets.

There are other theories as to why a Prius with the 1.8L engine so easily breaches its head gaskets and most of those have nothing to do with EGR. They are more focused on the limitations of the cooling system leading to overheat, which has been a classic cause of failed head gaskets across essentially all gasoline engines for 100+ years. I tend to put more stock in them.

The Prius has long been known for giving a "bathtub" graph for costs: Very expensive the day you buy it, then it plummets to little more than fuel and car washes, and then it rockets back up to the four (or five) figures at the end. Visualized, this is like the trough of a bathtub: |____|

The span of years between the start and end of that graph is variable, but in salty areas the average is pretty close to 15 years. Plenty of people have squeezed many more miles out of their cars, but if you look closely you'll notice that most of them slammed those miles on in the first 12-15 years.

I'll finish with the suggestion that you consider the cost trends of whatever your next car is going to be. You're in a good position to recover reasonable value* by trading or selling what you have now. If you let the car run to an expensive failure, there will be much less left to recover.

Would you rather get a good trade now on a "merely expensive" newer car, or a terrible trade value on one that has had time to go up even further?


*Ideally the best time to really get a strong trade is about year 14. This is because banks will write traditional used car loans on cars up to 15 years of age, so the dealers have a relatively easy time selling it for good money and can thus afford to pay the best trades. Once the car is 15 years old, it will most likely go to a buy-here-pay-here lot with alternative financing, the price ceiling will be a good bit lower and thus the potential trade amount is lower.