Hi BITOG! First post. Sorry this is a long post – feel free to ignore. I am just selfishly asking for advice. If you have the time to read this and help by chiming in, I would be grateful. If not, just move on. A week ago I bought my first car ever, a 1997 Toyota Avalon with 160k miles, for $2800. I am in my mid thirties and have lived most of my life in various European cities where all I really needed was public transportation, a bicycle, sometimes car rides from friends, plus the occasional rental car or friend lending theirs. I've lived in Northern California for the last 2 years and managed ok with the above, but finally bit the bullet and bought a car because I want to see more of the USA before I leave. I don't know when exactly I will be leaving, but here's an estimate: 20% chance to leave the US 1 year from now; 70% chance of leaving the US 2 years from now; 10% chance of staying 3 years or more in the US. As I am now rather low on money, I hope to avoid doing repairs on the car for the first year. I don't need the car for commuting or anything; I bought it just for road trips on holidays and weekends. Now that I have it, I will no doubt use it for other purposes too, but I expect to be racking up mostly highway miles. The '97 Avalon has the 1MZ-FE V6 engine infamous for sludge problems, especially if the oil hasn't been changed often enough (which applies to Toyota's 7.5k mile recommendation). This car is fairly well-maintained and has never been in an accident: I bought it from the original owner; it came with all the maintenance records, including a print-out for each oil change ever performed on the car, which were done twice a year at 4.5-5k mile intervals, mostly at Toyota dealerships, mostly with premium bulk dino oil, like Chevron Supreme 5W30 (which was used for the last 3 oil changes). Note: 5W30 was used year after year even in the summer for this Californian Central Valley car despite the manual dictating 10W30 for over 100ºF weather. Does this matter? I took it to a Toyota dealership for a pre-purchase inspection. The mechanic there said the car would be ok to drive as it is for a year, but eventually the slightly leaky valve cover gaskets (with 80k miles on them) would have to be replaced (a $300+ job because with the 1MZ-FE a lot of stuff needs to be removed for access) and they found oil at the bottom of the timing-belt cover, guessing the cam-shaft seals were leaking, and guessed that the timing-belt would also have oil on it and be weakened. However, the timing belt was changed 15k miles / 2 years ago, so it should last a little longer, even if weakened. Plus the engine (early 1MZ-FE, before VVT-i) is a non-interference (freewheeling) type, so if the belt snaps, the valves and pistons should not be damaged and all I need is a tow to get a new timing-belt. If I stay in the US for more than a year, I plan to do these $1000+ of repairs in about a year's time. If I sell it before, I will be upfront about the repairs needed. Car drips no oil at all where it is parked. Perhaps indicating another minor problem, the smog certificates show that HC (hydrocarbons) in the 15mph test were 51ppm in 2012 and 2014 (2013 and 2011 just say “pass”) when the max allowed was 52ppm. 2010 it was only 9ppm; and before even lower. I have no idea why the hydrocarbons are high lately, but at least they are consistent. Also, now that I've been driving the car for a week, it has stalled on start-up twice when starting when the engine is already hot: engine sounds like it starts, RPM goes to normal idle for maybe half a second, but then RPM drops and engine stalls in just one second. One time the next try started the car fine, another time it repeated this stall once and started third time fine. I have no idea what caused these stalls and would appreciate guestimates. Otherwise it runs and idles fine, with no weird sounds or anything. After buying this car and reading about the 1MZ-FE V6 engine sludge issues, I first thought I should try a preventative flush with something like Auto-RX, before reading that this might actually cause more problems by flushing gunk to where it hurts more (blocking a passage); that Auto-RX would make more sense after opening and manually cleaning the valve covers, which I hope to not do for a year because I am low on money (and don't have a garage of my own where to do it cheaply). Plus Auto-RX might also clean up gunk around cracked seals and exacerbate the minor oil leaks that the engine has. So, the opposite alternative is to continue business as usual, maybe decreasing OCI to 3k miles, with stuff like Chevron Supreme (and use 10W30 for summer, as mandated by the manual). The half-way option is to change to a full synthetic oil with more detergents, in the hope of gradually reducing gunk and sludge from the engine. For that, I thought Pennzoil Platinum/Ultra or Redline sound like they might have too much detergents without the seal conditioners to keep my oil leaks from worsening, so I was thinking more along the lines of Valvoline Maxlife or Mobil 1 High Mileage, which have both a lot of detergents and seal-conditioners, to keep the leaks from getting worse, while hopefully reducing sludge gradually or at least keeping it from getting worse, with an OCI of 3k miles to begin with. Is this a sensible approach? The car is due for an oil change, with 4k miles from the last one. I plan on doing a roadtrip to Grand Canyon and thereabouts in late May – early June, where it gets quite hot. So I was planning on using 10W30. If the new oil does dissolve some of the possible sludge inside the engine, does that impact at all what grade I should be using? I was also thinking that it probably wouldn't hurt to try to “rinse” the injectors with some sort of fuel treatment with detergents, something like Redline SI1 or Gumout All In One (other recommendations welcome). Admittedly I don't really know anything about these. I guess it would be best to do the “first flush” before the upcoming oil change, rather than with nice new oil. Regardless of what else I do, I plan to change the PCV valve very soon since it is cheap and easy to do and a gummed up PCV valve one is one the major reasons the 1MZ-FE gets sludge build-up. I guess I would be better changing to a new PCV valve with new oil? Or maybe it doesn't matter? Any comments on any of the things I mentioned are welcome. Thanks!