# Changing my oil question **URL:** \ **Category:** Factual Questions\ **Created:** [September 27, 2014, 4:36pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721 "2014-09-27T16:36:30Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [September 27, 2014, 7:02pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/21 "2014-09-27T19:02:55Z")
> [@Stratocaster](#): > > Joey P, I suspect that’s right re: the salt sea theory, in which case the oil would be a bit less dirty than it otherwise would have been. But from what I’ve read in this thread, nothing to depend on, and there doesn’t seem to be some sort of “rule of thumb” that says how much it might push out the need for a change. FTR, I would still recommend an actual oil change on a regular (or more than regular) basis. Since you’re burning oil, all that dirt and carbon is going through the cylinders and is going to cause other issue eventually. Whether it’s something cheap like ruining your spark plugs or something expensive like knocking because there’s so much carbon buildup that there’s extra compression in the cylinders. You might want to use some oil or fuel additives to keep everything cleaned out. ---
**Author:** ![RivkahChaya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rivkahchaya/32/8919_2.png) [@RivkahChaya](https://boards.straightdope.com/u/RivkahChaya)\ **Post date:** [September 27, 2014, 7:14pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/22 "2014-09-27T19:14:12Z")
> [@LSLGuy](#): > > The filter just gets dirtier & more full of gunk over time. And once it gets gunked up enough, it starts interfering with the flow of oil, leading to inadequate lubrication of moving parts. When you change the oil, you also change the filter for a fresh clean one. This, plus, any time the car is low on oil, which it is if the OP waits for it to be down a quart, or even half a quart before he fills it, the oil runs hot, and will burn even in the place it’s supposed to be, let alone in the cylinders when it slips past the rings. Burnt oil is ineffective oil, plus, burnt oil is reduced in volume, so it looks like you’ve lost even more, and it clogs the filter faster than unburnt oil. So, adding oil for the reason the OP is adding it is actually probably a reason to change it _more_ often, not _less_ often. In fact, changing it more often may result in having to add slightly less. Not none, and not so little that it makes up for the cost of the extra changes, but you reduce the risk of the engine suddenly oiling out, and becoming a giant doorstop in a couple of minutes flat. Honestly, I’d be scared to drive a car that needed that much oil added that frequently. Find someone who is looking for a parts car or a demo car, and sell, ASAP. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [September 27, 2014, 8:28pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/23 "2014-09-27T20:28:21Z")
A quart a week is excessive for normal driving habits, but what a lot of folks seem to be missing is that the OP puts 30k miles per year on this car. For what normal folks drive, it’s more like the equivalent of a quart every month or so. When you are losing oil like that, you’re most likely either talking about a leak (which the OP has said wasn’t the case in their car) or well worn piston rings. Those advocating getting this fixed seem to be ignoring the fact that redoing the piston rings is basically an engine rebuild. It’s not a $400 job. This is more like a $2000 to $3000 job. You have to go through an awful lot of oil before an engine rebuild makes any kind of economic sense. The OP is probably better off running the car into the ground and buying a new one. On most cars, getting the oil changed regularly isn’t anywhere near as crucial as some folks make it out to be. I had an old Nissan pickup truck, and like most Nissan pickup trucks, the thing ran forever but rusted apart. A friend of mine nicknamed it the Bondo Bandit and refused to park next to it. When it got to 200k miles, I stopped doing all maintenance on it, including oil changes, and waited for it to die so that I could get a new truck. It went for 5 years and over 60,000 miles without an oil change. Never lost a drop of oil, and had no engine problems at all. The fuel pump (which is in the gas tank, not related to the engine at all) finally went out on it. I could have fixed it fairly easily, but I used that as an excuse to finally junk it. Note that I’m not recommending that you ever do this to one of your vehicles, just showing that as long as you’ve got oil in the engine, even old oil, chances are you aren’t going to do any major damage. Some engines, however, have a tendency to build up sludge. If you don’t change the oil on these regularly, the sludge builds up and blocks the flow of oil, and then the engine self-destructs from the lack of lubrication. No cite, but I’ve heard that a lot of Toyota engines fall into this category. Based on the potential sludge issue, if I were the OP, I would probably change the oil every 3 months or so. That’s a bit more than every 5,000 miles, but should be often enough to prevent any sludge problems. That’s just my opinion, though. For a factual GQ response, no, there is no consensus on what to do here. A lot of mechanics fall into the category of YOU MUST CHANGE THE OIL OFTEN OR ELSE VERY BAD THINGS HAPPEN and a lot of others are like eh, don’t worry about it so much. I’m just an idiot back yard mechanic, but I’m in the latter category. I have a Dodge Dakota pickup that was basically in the same shape as the OP’s Toyota. I had to put a quart of oil in every month or so (I drive it a lot fewer miles than the OP). It’s run that way for about 100k miles (it has a total of just shy of 200k miles on it now). I changed the oil about every six months. The engine still runs fine. The frame, on the other hand, is not so fine. The part that holds the rear leaf spring in place rusted and snapped, and the frame cross member in the back also rusted and snapped. So basically the only thing holding the back of the truck together is the weight of the bed on top of the suspension. So now it’s sitting in my driveway waiting to get scrapped. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [September 27, 2014, 8:41pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/24 "2014-09-27T20:41:14Z")
I have a 2000 Saturn. It burns one quart of oil every two weeks. My wife’s car is a 2001 Saturn. It burns one quart of oil every week. So I’m always checking and adding oil to the cars. I don’t mind. It’s _much much_ cheaper to simply add oil versus fixing the problem (likely the rings). And I change the oil filters a couple times a year. I’ll keep doing this until something major goes wrong. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [September 27, 2014, 8:44pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/25 "2014-09-27T20:44:21Z")
> [@Stratocaster](#): > > I buy it at Walmart, in 5-gallon containers. Forgot to mention that, because I go through so much oil, I _ **only** _ buy oil at Walmart in 5 quart containers. I buy the cheapest 10W-30 on the shelf. ---
**Author:** ![RivkahChaya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rivkahchaya/32/8919_2.png) [@RivkahChaya](https://boards.straightdope.com/u/RivkahChaya)\ **Post date:** [September 27, 2014, 9:01pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/26 "2014-09-27T21:01:04Z")
I judge when to do a change by the color of the oil, the mileage, and the time. I do one every 10,000 miles, regardless, but that rarely happens. I do one every six months regardless. I do one if the oil is getting dark, AND it’s been more than three months. Right now, my car is going on four months/2,000 miles since the last oil change, and the oil is almost the same color it was when it went in, so I won’t be changing it soon. The car is 20 years old, but has been pretty well maintained. One of my cousins drove it in Chicago for about 8 years, which, if people don’t know, is notorious for using a really corrosive salt that causes body rust. As a result, the catalytic converter back was replaced several years ago, although after 14 years, it wasn’t a bad run. More unusually, the gas tank had to be replaced, and I put lines in as well. I found someone who would do it along with brakes and tires when the car was already up on the lift, so I got a deal. Even with the repairs a 20-year-old car needs, I still average less than $100/month, and that includes retrofitting it with a new AC system a couple of years ago after a week of 100’F+ temperatures. I’m pretty amazed the car doesn’t burn oil, but it doesn’t lose any at all between changes, and the color has me convinced it isn’t mixing with radiator fluid, or anything. ---
**Author:** ![Stratocaster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/stratocaster/32/16393_2.png) [@Stratocaster](https://boards.straightdope.com/u/Stratocaster)\ **Post date:** [September 27, 2014, 10:03pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/27 "2014-09-27T22:03:30Z")
> [@engineer\_comp\_geek](#): > > When you are losing oil like that, you’re most likely either talking about a leak (which the OP has said wasn’t the case in their car) or well worn piston rings. Those advocating getting this fixed seem to be ignoring the fact that redoing the piston rings is basically an engine rebuild. It’s not a $400 job. This is more like a $2000 to $3000 job. You have to go through an awful lot of oil before an engine rebuild makes any kind of economic sense. The OP is probably better off running the car into the ground and buying a new one. That is essentially my strategy, and you described what I was told much better than my feeble attempt to recreate it. “Can this be fixed?” “Yeah, but it’s a really big job.” The car runs great. I’ll keep putting oil in it until it doesn’t, then I’ll buy a new car. ---
**Author:** ![Stratocaster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/stratocaster/32/16393_2.png) [@Stratocaster](https://boards.straightdope.com/u/Stratocaster)\ **Post date:** [September 27, 2014, 10:06pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/28 "2014-09-27T22:06:27Z")
> [@Crafter\_Man](#): > > Forgot to mention that, because I go through so much oil, I _ **only** _ buy oil at Walmart in 5 quart containers. I buy the cheapest 10W-30 on the shelf. Yep, I meant 5-quart (not 5-gallon). Whatever’s cheapest. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [September 27, 2014, 10:13pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/29 "2014-09-27T22:13:51Z")
If your car lets out a big puff of smoke after idling or when first starting there is a good chance valve seals could fix the problem, I am not familiar with your engine but sometimes seals can be done very inexpensively. ---
**Author:** ![DingoelGringo](https://avatars.discourse-cdn.com/v4/letter/d/9d8465/32.png) [@DingoelGringo](https://boards.straightdope.com/u/DingoelGringo)\ **Post date:** [September 27, 2014, 10:39pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/30 "2014-09-27T22:39:28Z")
> [@Stratocaster](#): > > We have emissions tests, and so far, no problem passing them.Maple syrup. > > Hmm, I do get your Dead Sea theory. But even if that’s true (if I’m following), the contaminants that remain (if they are the salt in the analogy) would still ultimately be diluted within a full complement of oil, and the oil would be no less dirty (but no more) than if I wasn’t burning and replacing oil. I think. IOW, unlike new salty water, the new oil has no contaminants. But the “old” contaminants could still be in there, obstinately refusing to burn a portion through the tailpipe along with the oil. In which case, my frequency for changing oil, whatever it was, wouldn’t be affected. I’d drain the oil and use one of the newer synthetics. They’ve been around a couple of decades, so don’t know why i called them new, but give it a try and see if the consumption doesn’t go down. ---
**Author:** ![GreasyJack](https://avatars.discourse-cdn.com/v4/letter/g/df705f/32.png) [@GreasyJack](https://boards.straightdope.com/u/GreasyJack)\ **Post date:** [September 27, 2014, 10:48pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/31 "2014-09-27T22:48:49Z")
There’s basically two reasons why you change your oil. One is you get viscosity breakdown and the oil itself stops lubricating. The other is contaminates that build up in the oil. With modern cars using modern motor oils, you can go a _really_ long time before you start getting viscosity issues. Removing contaminates is the limiting factor by a wide margin. With an oil burner, you’re replenishing the oil but (if it is the rings) the contamination issue is actually _worse_ because the same weak rings that are letting oil into the combustion chamber are also letting way more combustion gasses past into the oil. If anything, you probably ought to be changing it _more_ than usual. I will say that an '08 Rav4 is a pretty nice car, even with 175k on it. Unless you’re really jonesing for a new car, the better option for when it does finally die would be to just throw a used engine in. If it were my car, I’d probably consider just doing it now since if it really is burning close to a quart every 500 miles, it’s a matter of when not if the engine goes for good. > [@Senegoid](#): > > OP, do you live in a state with required smog checks? If you’re smoking oil, you may have a problem passing that. Believe it or not, burning oil generally won’t cause you to fail an emissions test. They’re supposed to fail you if you’ve got visible smoke, but beyond that at least in the states I’m familiar with their equipment doesn’t detect it. Especially now that many states don’t do tailpipe inspections at all. You can burn a _lot_ of oil before you start actually seeing smoke. Last time I lived in a smog state I had a truck that near the end was doing about a quart/300 miles. It would smoke coasting on the highway and such, but it behaved itself at the smog station and never had a problem passing. Although a bad oil burning problem is also likely to eventually foul the catalytic converter, which _will_ cause the car to fail. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [September 27, 2014, 11:18pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/32 "2014-09-27T23:18:09Z")
I would say you may need more frequent oil changes under the circumstances that you mention (or hint at), not less. If the ‘barrier’ between combustion and lubrication has broken down as much as it seems your oil is shooting through it’s life very very fast, the oil you lose is really inconsequential to this, so you will in addition to the added new oil will have some very old depleted oil. If you were however leaking oil on the ground at that rate you may never need a oil change or even a filter change as that is how old cars used to be lubricated (and modern oil filets once clogged will break thru so it would be unfiltered, but the replacement rate would make up for this). ---
**Author:** ![JerrySTL](https://avatars.discourse-cdn.com/v4/letter/j/e274bd/32.png) [@JerrySTL](https://boards.straightdope.com/u/JerrySTL)\ **Post date:** [September 27, 2014, 11:39pm UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/33 "2014-09-27T23:39:41Z")
> [@dolphinboy](#): > > It’s certainly not great for the environment to burn copious amounts of oil. A quart of oil versus many gallons of gasoline over the course of a 1,000 miles isn’t that big of a deal. They are both hydrocarbons taken from crude oil. Of course the car’s emission system deals with the unburned hydrocarbons of gasoline and I doubt that the catalytic converter does much with engine oil. ---
**Author:** ![HoneyBadgerDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/honeybadgerdc/32/1033_2.png) [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)\ **Post date:** [September 28, 2014, 12:01am UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/34 "2014-09-28T00:01:08Z")
I switched to synthetic about 30,000 miles ago and my consumption stayed approx the same. ---
**Author:** ![RivkahChaya](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/rivkahchaya/32/8919_2.png) [@RivkahChaya](https://boards.straightdope.com/u/RivkahChaya)\ **Post date:** [September 28, 2014, 12:34am UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/35 "2014-09-28T00:34:22Z")
> [@GreasyJack](#): > > I will say that an '08 Rav4 is a pretty nice car, even with 175k on it. Unless you’re really jonesing for a new car, the better option for when it does finally die would be to just throw a used engine in. If it were my car, I’d probably consider just doing it now since if it really is burning close to a quart every 500 miles, it’s a matter of when not if the engine goes for good. I threw a used engine in my uncle’s 72 Chevelle when it was about 18 years old, and hit 180,000 miles, because one of the cylinders failed so badly, it had no compression at all. I used to do points and plugs on this car. I bought an engine from an 80’s Pontiac that had been in a bad rear end accident; engine cost $400, and it fit on the block, which we had steamed and checked for cracked. It was usable. The guy put the engine on the block, gasketed everything, and hooked up the engine mounts for another $400, but I had to transport the engine myself. I regasketed the cylinder head after having it machined; I also replaced freeze plugs on the engine before it was installed. I rebuilt the carburetor, and installed the new distributor, which had a rotor (no more points! yay!) and hooked all the electrical systems. While I was at it, I changed belts and hoses, and flushed the engine. I’d had the radiator pressure tested, and it was good. It ran for 10 more years. Probably would have run for even more, but my uncle wanted something smaller, gas efficient, and with safety options like airbags. We sold it to a collector who was either going to try to restore it or use it for parts. Chevelles were really big for a while. I realize that $800 to switch out an engine for this car is too low an estimate, but it will be less than the estimate for the ring job, and the engine will be better than the one I put in the Chevelle, and won’t need all the tinkering I did. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [September 28, 2014, 1:05am UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/36 "2014-09-28T01:05:47Z")
> [@Joey\_P](#): > > > [@LSLGuy](#): > > > > I’m surprised somebody hasn’t mentioned this already … the oil filter. > > I did. ☹ Sorry. Your post wasn’t there when I downloaded the thread & wrote my reply. It was there when I posted my response. I shoulda ETA’d but didn’t. ---
**Author:** ![Duke\_of\_York](https://avatars.discourse-cdn.com/v4/letter/d/f6c823/32.png) [@Duke\_of\_York](https://boards.straightdope.com/u/Duke_of_York)\ **Post date:** [September 28, 2014, 1:21am UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/37 "2014-09-28T01:21:37Z")
Maybe this will help. > **[Wynns Stop Smoke Oil Treatment 325ml | Halfords UK](https://www.halfords.com/motoring/engine-oils-and-fluids/fuel-and-oil-additives/wynns-stop-smoke-oil-treatment-325ml-176610.html)** > > Shop the latest Wynns Stop Smoke Oil Treatment an oil soluble supplement, reduces exhaust smoke due to oil burning. at Halfords UK FEATURES & BENEFITS OF WYNN’S STOP SMOKE OIL TREATMENT Reduces exhaust smoke due to oil burning Improves the viscosity properties of the oil at high oil temperatures Seals the gaps between worn engine components Improves compression and engine performance Reduces engine noise Ensures a strong protective oil film under high temperature conditions Is compatible with all mineral, synthetic, single and multigrade oils Will not harm catalytic converters Suitable for petrol, LPG & diesel engines Ideal for cars with excessive blue/grey exhaust smoke due to oil burning Especially effective in older engines with worn components View the Safety Data Sheet ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [September 28, 2014, 1:43am UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/38 "2014-09-28T01:43:20Z")
Its getting late in the year here for higher viscosity oils but you can reduce the amount of oil lost in some cases by using straight SAE 30 or SAE 40 oil. Most of the close tolerances in the engine that require a smaller molecule like a SAE 20 or the 5W-30 will be worn enough so that a 40 weight will probably do just fine until cold weather becomes an issue. Don’t ask me where i got this idea 😛 And first assumption as to cause of oil consumption will be valve guides. And the Cat and EGR system will keep the blue smoke much much reduced from the days long ago. ---
**Author:** ![actualliberalnotoneofthose](https://avatars.discourse-cdn.com/v4/letter/a/e79b87/32.png) [@actualliberalnotoneofthose](https://boards.straightdope.com/u/actualliberalnotoneofthose)\ **Post date:** [September 28, 2014, 4:09am UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/39 "2014-09-28T04:09:42Z")
> [@Stratocaster](#): > > Way less cost than that. I buy it at Walmart, in 5-gallon containers. And unless I’ve been misinformed, this is not a $300 or $400 fix. I’ll probably be getting a new car soon, I’m not spending one or two thousand to get this fixed. > > Besides, I’ve already acknowledged my horrible shame. Can someone actually answer the question posed? Hey, maybe I’ll buy it from you. I have no problem with the shame, and I live in a civilized place that apparently has fewer regulations and laws against being poor and that sort of thing. So, as long as I don’t tell busybodies on the internet no one will lock me up or take away my children for burning oil. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [March 6, 2021, 9:41am UTC](https://boards.straightdope.com/t/changing-my-oil-question/699721/42 "2021-03-06T09:41:37Z")
damn. How did this get to the top of my reading list? [Previous page](https://boards.straightdope.com/t/changing-my-oil-question/699721.md?page=1)