High Mileage Preventative Maintenance

[Loya1ty]

I've always stuck to the maintenance intervals and will remain to do so, but I'm trying to determine the parts that may be worthwhile to get done over the next 2 months so I don't need to worry about it later (i.e. approaching and past 200k).

 

I'll need to do the 180k service next year and am budgeting that out, so the goal here is to absorb some cost now on potential unforeseen bits rather than when I (hopefully) buy a house next year as well.

 

What I plan/thinking to do over the next 2 months at ~170k miles that aren't included in normal maintenance guidelines:

Coolant flush along with radiator hose and clamp replacements. anyone else do this and at what miles/why?

Engine and/or transmission mounts - is this really needed for efficiency or just nice to have for ride quality?

02 sensor replacement - I'm thinking this will help my MPGs and overall engine running (use to get 28ish, now around 25mpg) Any experience with the brands in the attached photo (otherwise I'll just get Bosch)?

exhaust leak test and seal if any

putting some fuel additive the next 2/3 fillups

Valve Spring replacement or cleaning - last time at the shop it was mentioned some noise coming from that area. I'd have them do that work most likely.

 

Insight is much appreciated. I know there aren't a whole lot of us with high mileage 5th gens, and some of you GT folks like to replace all your parts at any given time anyway but just trying to clean the car up for the long haul so i don't have to buy a new car due to death (last 2 times), but can choose my next toy while having a low cost daily. It's been a great steed thus far.

[ibr_adam09]

Do a compression test or leakdown test.

On your next oil change, send a sample to BlackStone Labs. An analysis report will give you an idea on the health of your engine based on the wear elements in the oil.

I'd stick with name brand on the o2 sensors (like Denso, Bosch)

I'd change the mounts, at 180k, the rubber is or will soon be shot

[rgeo13]

^^x2 for blackstone lab test. $28 but can tell you a whole lot. For an extra $10 you can have them test the life of the oil to give you a better heads up on intervals. For example, if you change oil every 5k, they may say "oil looks great, try a 7k interval". Knowing how your oil holds up under your specific driving habits and engine can allow you to personalize your interval and make sure you aren't changing it too soon...or too late. Which can save you money.

[Scubaboo]

I do coolant maybe every year or two. I want the system to be clean and rust/gunk free. I see a lot of turbo Subarus with gunky cooling systems and I believe it's because these engines are hard on coolant as it is also used to cool the extremely hot turbo. Hoses get hard over time so they do need to be replaced periodically, but they arent as bad as some cars like early 2000-era BMW's that have cooling systems pressurized so high that they kill hoses often. If they get crunchy when squeezed or turn brownish I will replace them, if not probably at around 100k or so.

 

Mounts I replace when they are physically broken. Can be hard to see on some style mounts so I also check by reving in place and looking for excessive engine movement. They can be replaced earlier and can improve NVH slightly.

 

O2 sensors IMO I would spring for an OE/OEM part. They last so long and have a direct effect on engine operation and are relatively cheap so I dont see the need to gamble with other brands. I'd be interested to hear if people have had luck with replacement brands though.

 

Second the suggestion of a more comprehensive check up including compression and leakdown. Rebuilds are expensive but a pre-emptive one will be cheaper and easier than one done because of a failure that grenades the engine.

 

Also, you are probably due for your 2nd/third timing belt service by now?

[Loya1ty]

Great info, thanks! I'll definitely do the oil analysis and ask the shop to perform a compression test and exhaust leak test (I could probably do myself, but rather not).

 

I also thought it odd that they don't recommend a coolant flush often (I think I read somewhere every 11 yrs or something random).

 

Still undecided on the mounts, but I'm sure they're abused from PA winters. Will most likely do them for peace of mind. It's probably me being paranoid, but I feel as though I can feel some shaking at certain times during idle or specific RPM. The thing about the boxer engines is it's easier to feel the shakes horizontally, vs vertical vibrations working against gravity.

 

And something I found out around 125k is they don't have the typical timing belt, but a chain instead. I guess it can be adjusted based on readings. So took care of the water pump, drive belt, pulleys, and tensioners then. Don't plan on revisiting those before the car is gone.

[Scubaboo]

^Just saw you have a '13 2.5 and yeah those have chains.

 

Yeah I never saw the coolant flush interval but I think it was either not mentioned or some random long time. Not good for a car you plan to keep a while.

[dgoodhue]

Coolant change interval is 135k miles for my 2012 and every 60k miles after that. [i am not sure about the FB25.] I would replace the radiator cap as it is cheap and some have overheated the engine due to malfunctioning radiator cap. The 5th Gen EJ253 & EJ255 has a 60k mile interval for the fuel filter assembly as well.

 

For my 2.5i Outback (I would have done the same with my 2.5i Legacy as well), I am just following the factory service intervals, change the differential, transmission fluid, power steering fluid and replace what breaks as it happens. I don't know if your really going to prevent any significant repairs.

[colinmi]

I did the my radiator hoses at about 100k while I had it apart to do the timing belt and water pump. When I hit 200k I'll do the same thing I think. Don't forget that other little hose on the water pump when ordering the parts.

Its good to have a plan on replacing anything made of rubber.

Check the CV joint boots on your axles. Replacing them before they split and let dirt eat up the joints can save a lot of money. Especially check the front one closest to the exhaust. I'm planning on replacing mine when I do the struts this summer.

[ehsnils]

I'd like to add the following:

 

• Transmission fluid changes, also for the differentials.
  
• Remove the injectors and have them checked/cleaned to make sure that they are good and are giving equal amount of fuel. Too lean on one cylinder can give you a burnt valve. It will also help the fuel economy.
  
• Valve clearance check and correction if needed. Even if the compression test checks out this is good to do.
  

[Robert L]

IMHO, change oil regularly, keep up on filters and plugs, and forget the rest. I know this portably is not a popular view as we all like to work on our cars but from someone who routinely puts 300,00 to 400,000 miles on his cars it has worked best for me. Hoses, clamps etc are designed to last a lifetime, or at least 10 years, in over 50 years of driving and working on cars, I have never had one burst.

 

Also, again IMHO, oil analysis are a waste of money, as the results are not going to change what you do with the engine. For instance it they discover a high level of a wear metal are you going to rebuild the engine? There is a saying in medicine, that says, if the test results do not change your treatment plan, don't do the test.

[Scubaboo]

Man I wish I could get away with putting 300,000 to 400,000 on any car with just plugs/oil/filters.

[DrD123]

Yeah - for long term operation with an EJ engine, don't forget the timing belt at 100k miles - it's an interference engine. For the FA/FB engines, you are going to want to do a decarboning operation periodically (I think most recommend 30k miles or so) as the lack of port fuel injection means no fuel washing the valves, which means significant carbon buildup which will rob performance. (I figure with time, that issue will be solved with direct injection engines, but for now it's an issue with most of them). Also - particularly if you live somewhere where it rains a bunch or is humid, replace the brake fluid (flush out through to the calipers) to prevent corrosion/damage which can result in failed seals, etc. Replace oil, coolant, PS fluid, and (if you have an MT) the clutch fluid (brake fluid) per the normal intervals. I flush the clutch when I flush the brakes, which is relatively infrequently for me as I live in a desert and the fluid is almost clear after 3 years, which is my normal interval. Other than that, I agree - filters and plugs, then just fix whatever is leaking/broken/worn out, or if you want to improve handling or something (upgrade). In general, we dump cars when either they are requiring too much maintenance (our van was leaking from the RMS, PS rack, etc. when we got rid of it at 285k miles) or it gets hit and totalled by a fellow New Mexican (drivers around here are, well, really bad)

[Loya1ty]

wholly revival, batman lol. Covid has significantly reduced the amount of miles I've put on the car... so I've literally done none of the things I've laid out in my initial post

 

edit.. okay I guess I did put some high mileage additive in a few fill ups haha it did seem to make it run smoother, but could have just been placebo.

Edited December 9, 2020 by Loya1ty