RE: Oil change opinions

[firefighterjake]

I change out the oil in my WRX religiously every 3000-5000 miles as most owners recommend doing so due to the turbo and possible issues with bearings.

The other day I changed the oil and then looked at my wife's Legacy and was mildly surprised to see that it's been close to a year since I did the oil in her car.

Now before you think I am a terrible mechanic (which I am incidentally) I should add that I did the 12,000 mile maintenance at 11,500 back in 2016 and now, almost a year later, she is up to a whopping 14,500 or so miles -- well below the recommended 6,000 mile oil change interval, but well over the "or six months" interval.

Since she was out of work for so long and then landed a local job with a 10 minute commute she just didn't put on the mileage.

So here's my question: just how bad is it to not adhere to the time interval vs. the mileage interval. I mean to say I can completely understand the mileage as a moving vehicle = wear and tear on the engine and the oil being actively filtered. However, an unmoving, unstarted car would not have any wear and tear, right?

 

[festerw]

I wouldn't be terribly concerned, the short commute would be the only worry if it doesn't get up to operating temp.

Sitting is mostly a concern because with temperature swings you'll get condensation. Parked in a garage is better but it can still happen.

My parents have a similar distance and we change theirs once a year for the last 5 years and it still runs great for a nearly 300k engine.

 

[peakbagger]

My ford fiesta doesnt really have an oil change interval, it adjusts the interval to the type of conditions the car is run through. I run very long trips for work and not a lot of short runs, I go at least a year and usually have it changed when in for my sticker. I have run synthetic for years, the oil can last much longer than a year. One of the synthetics used to push a super oil filter which extended the oil change interval for years. Turbos have 99% of their wear during start up and shut down. There used to be device called a turbo luber that would keep oil flowing after the engine was turned off. Most turbos recommend idling for few minutes prior to shutting the engine off to cool the bearings down. Most companies that sell turbos recommend synthetics.

 

[jatoxico]

I'm with these guys ^^^, wouldn't worry about it. Check the dip stick and see how the oil looks, prob good idea to give the car a good long run now and again.

 

[brenndatomu]

I don't pay much attention to those time interval recommendations...I don't know anyone who does...

 

[aaronk25]

And here lies the problem. Oil that has been run continuously becomes more acidic. I don’t believe in condensation from weather or sitting but do very much believe that based on how much anti acid is left in your oil near the end of a oil change you might be out if anti acid reserves in the oil.

Acidity comes from combustion blow by that gets past the rings, valve guides ect. If the vehicle sits unused for a period of time, say 2 weeks or a month, with oil that is acidic, then rust and corrosion start particularly on smooth surfaces such as cylinder walls. When you start the engine the piston rings scrape off the corrosion/rust and what is left is slight pitting of the surface which will eventually wear down rings and cause high oil consumptions.

It’s almost impossible to wear a engine out that’s run frequently but we “rust or corrode” them out all the time. Especially in aircraft and boats where they sit unused a long time. This is why before extended periods of storage the oil should be changed, not when it’s ready to be commissioned but prior to layup.


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[firefighterjake]

OK . . . sounds like I'm probably good then.

Both the WRX and my wife's Legacy require synthetic oils and she does a "longer" ride (30-45 minutes) about every three or four weeks and is typically driving locally about once a week.

I may change the oil though just to be on the safe side since as I say it has been nearly a year.

 

[peakbagger]

You must be lucky with your Subaru's, I know more than few folks who ended up changing their oil 1 quart at a time as they are always adding oil

 

[firefighterjake]

You must be lucky with your Subaru's, I know more than few folks who ended up changing their oil 1 quart at a time as they are always adding oil

So far, so good. I know some Subarus in the past have had oil usage issues.

My wife was "lucky" enough to have a head gasket issue with her last Legacy, but she still loved the way Subarus handle in the snow and opted to buy another.

 

[blades]

head gasket- seems to be a common issue on Subaru's of late.

 

[jatoxico]

So far, so good. I know some Subarus in the past have had oil usage issues.

My wife was "lucky" enough to have a head gasket issue with her last Legacy, but she still loved the way Subarus handle in the snow and opted to buy another.

Had the same head gasket issue on wife's Legacy. Became a known problem with our year (2004) over the time we owned it. Subaru's official factory fix, which they never communicated to us, was to add radiator leak stop . Ended up having the dealer do the head gasket (who promptly wrapped an O2 sensor around the axle) then a couple years later we rebuilt the tranny . She finally overheated it so I traded it. Wife put 120K+ on it and it was very good in the snow car but left me with mixed feelings on Subaru.

 

[firefighterjake]

head gasket- seems to be a common issue on Subaru's of late.

Well "as of late" being a 2003 Legacy . . . we'll see if the problem pops up on this one.

 

[fbelec]

what years are the head gasket issues and what motor?

 

[firefighterjake]

what years are the head gasket issues and what motor?

I don't remember the motor or years ...,but I thought they finally lived that problem.

 

[jatoxico]

Was the 2.5 non-turbo esp early-mid 2000's.

 

[semipro]

In the shops that I worked in many of us would periodically re-torque the head bolts on cars with aluminum heads to prevent head gasket failure. This was done one bolt at a time in the specified order and was not done on engines with the torque-to-yield type head bolts. I've always done this on my vehicles and have never had a head gasket failure.

The theory is that aluminum expands more under heat so the head bolts stretch more than on cast iron heads. Re-torquing compensates for that stretching. It may also be why manufacturers went to torque-to-yield type head bolts as this makes the bolts act more like springs rather than solid.

Edit: I change the oil every 5k miles or when the oil maintenance system light comes on for my vehicles that have one.

 

[Dobish]

i didn't change the oil in my wrx for about 3 years... i just kept adding some when it got really low! Not surprisingly, I blew a head gasket....

I drive about 10 miles per day in Ole Rusty, so it takes me forever until I have to change the oil....

 

[fbelec]

question: in the ford 302 the heads ran so hot that the oil would sludge up so bad that the oil would all get pumped up to the head via the push rods and the return holes would get blocked. did many of these in my day. now for the question. would synthetic oil do the same thing?

 

[Seasoned Oak]

Change oil once a year in each vehicle. At inspection time. I only put a few thousand miles on each one, but a year is long enough in IMO . I only use synthetic oil. Still have few quarts of that graphite oil from the 70s in my garage.

 

[EatenByLimestone]

I put 5k on my truck this year. Most of that was driving to the cabin, 90 miles away and back. I'm on oil I put in last January. I think I'll have the oil changed today as winter is almost here.

 

[DickRussell]

.... I know some Subarus in the past have had oil usage issues.

My wife was "lucky" enough to have a head gasket issue with her last Legacy....

My son got burned on a used Legacy he bought from a private party. The head gasket went and the cost to fix wasn't worth it. But he got another Subaru, this one a more recent Crosstrek. I think they are basically a good car.

On the oil consumption issue, some Subarus, from I think 2011 to 2015, were on a list of cars that had excessive oil consumption. As mfg tried everything to boost CAFE, some things had unintended consequences. After a few years that had been addressed. Subaru actually had a decent criterion, over a third of a quart per 1200 miles, that would qualify for a fix, mostly a new short block. My wife has a 2012 Forester that was on the list. When we got the notice, it was time for an oil change anyway, but I pulled the dipstick right away, and saw nothing on it! The place where I had an oil change done two days later said it was down about three quarts, out of about six. When it was time for the next change, I took it to the dealer where we got it. They started the 1200 mile test run, and I noted that following the change the oil was right at the "full" mark. Naturally I monitored the drop in reading on the dipstick as time went on. On the morning I drove it back for the end of the 1200 mile check, I noted that it was near or past about a third quart low. After they had the car in the shop for almost a half hour, out of my view of course, they came back and said no problem, the level was right where it ought to be, and no further action was needed. I out went with them to check, and sure enough the level was near the full mark. I was disgusted, and left. It would have been my word against theirs. After I got home, and the engine cooled down in the garage, I pulled the stick and noted that not only was there more oil in there than when I left home in the morning, but there was more oil in there than at the start of the 1200 mile check! They had added about a half quart oil out of my view, invalidating the test.

After a couple of months, and reading online that a retest was possible, I took the car to another dealer. After a second 1200 mile test run, the service manager there, in my presence this time, verified that the consumption was indeed significantly more than the allowed amount, and declared that we needed a new block. By then the car had over 80K miles on it. A few days later, while using a loaner car from them, ours was ready with a new block, all at no cost to us. Now, do you think I ever will go back to the first dealer, even to let them wipe the windshield?

 

[firefighterjake]

My son got burned on a used Legacy he bought from a private party. The head gasket went and the cost to fix wasn't worth it. But he got another Subaru, this one a more recent Crosstrek. I think they are basically a good car.

On the oil consumption issue, some Subarus, from I think 2011 to 2015, were on a list of cars that had excessive oil consumption. As mfg tried everything to boost CAFE, some things had unintended consequences. After a few years that had been addressed. Subaru actually had a decent criterion, over a third of a quart per 1200 miles, that would qualify for a fix, mostly a new short block. My wife has a 2012 Forester that was on the list. When we got the notice, it was time for an oil change anyway, but I pulled the dipstick right away, and saw nothing on it! The place where I had an oil change done two days later said it was down about three quarts, out of about six. When it was time for the next change, I took it to the dealer where we got it. They started the 1200 mile test run, and I noted that following the change the oil was right at the "full" mark. Naturally I monitored the drop in reading on the dipstick as time went on. On the morning I drove it back for the end of the 1200 mile check, I noted that it was near or past about a third quart low. After they had the car in the shop for almost a half hour, out of my view of course, they came back and said no problem, the level was right where it ought to be, and no further action was needed. I out went with them to check, and sure enough the level was near the full mark. I was disgusted, and left. It would have been my word against theirs. After I got home, and the engine cooled down in the garage, I pulled the stick and noted that not only was there more oil in there than when I left home in the morning, but there was more oil in there than at the start of the 1200 mile check! They had added about a half quart oil out of my view, invalidating the test.

After a couple of months, and reading online that a retest was possible, I took the car to another dealer. After a second 1200 mile test run, the service manager there, in my presence this time, verified that the consumption was indeed significantly more than the allowed amount, and declared that we needed a new block. By then the car had over 80K miles on it. A few days later, while using a loaner car from them, ours was ready with a new block, all at no cost to us. Now, do you think I ever will go back to the first dealer, even to let them wipe the windshield?

A Tale of Two Dealers . . . I suspect one has permanently lost all sales -- not to mention service and parts . . . while the other has earned your business.

 

[blades]

SOP, Went through that kind of thing with a Nissan dealer in early 80's ( dealer long gone now). What is particularly infuriating is this always seems to take place in warranty situations, if it's out of your wallet no problem.

 

[Marshy]

I change out the oil in my WRX religiously every 3000-5000 miles as most owners recommend doing so due to the turbo and possible issues with bearings.

The other day I changed the oil and then looked at my wife's Legacy and was mildly surprised to see that it's been close to a year since I did the oil in her car.

Now before you think I am a terrible mechanic (which I am incidentally) I should add that I did the 12,000 mile maintenance at 11,500 back in 2016 and now, almost a year later, she is up to a whopping 14,500 or so miles -- well below the recommended 6,000 mile oil change interval, but well over the "or six months" interval.

Since she was out of work for so long and then landed a local job with a 10 minute commute she just didn't put on the mileage.

So here's my question: just how bad is it to not adhere to the time interval vs. the mileage interval. I mean to say I can completely understand the mileage as a moving vehicle = wear and tear on the engine and the oil being actively filtered. However, an unmoving, unstarted car would not have any wear and tear, right?

Oil can oxidize when exposed to air. That causes the oil to breakdown. I personally don't think it's a major concern as I've never had a problem if I put fresh oil in a motor and stored it for 5 months. After storage I'll drive it for the 3000 miles before I change it.

You should be more concerned with your wife's car driving short commutes and not getting fully up to temp. This will cause condensation and will emulsify the oil causing sludge and deposits. Especially in the colder season.

 

[jatoxico]

I have a sense that because these days oils are formulated to go far beyond the old 3000 mi interval that the add packs are much better at buffering acids and other time associated problems. Don't have any first hand knowledge on that though.

As I said before I do think running the car to temp periodically is important.