Car Maintenance You Can Still Do Yourself

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Is it harder – or easier – to work on “new” cars?DIY 1

Many people have been intimidated  into submission – and don’t even check their car’s fluids anymore. This is too bad – because while it’s true new (and recent vintage) cars are more complex than cars have ever been, in some ways, they’re actually easier to work on.

The bottom line is you can still do a lot yourself – and save yourself both time and money. For instance:

* Serpentine belt –DIY 2

Many late-model cars have just a single “serpentine” belt that drives accessories like the air conditioning compressor, the power steering pump, the water pump, alternator and so on. In the not-so-good-old-days, it was common for each accessory to be driven by its own belt. Many engines had at least two and more often three belts to deal with. Not only that, but each belt had to be tensioned correctly by manually applying leverage, then tightening the bolts that held the item in place. It was actually harder to change/adjust belts in the old days than it is today. Because today, if your car has a serpentine belt, you only have one belt to change – and the tension is taken care of for you by an automatic tensioner. Typically, the job involves nothing more complicated than using a wrench or socket to apply some force to the tensioner, in order to release the tension on the belt – which can then be slipped off the pulleys. To install, just work the belt around the pulleys (follow the diagram on the sticker under the hood – most cars have these) and then, using your wrench or socket to leverage the tensioner, slip the belt over/around the tensioner pulley – and release. The correct tension will be set automatically – and you’re all done. This is a job that can still be done by an average person – with basic tools – by the side of the road, if need be. Don’t be afraid. It’s actually simpler than it used to be in the days of multiple drive belts. Serpentine belts can last a long time – 50,000 miles or more – but it’s a good idea to check annually for signs of pending problems such as cracks, which indicate the the belt material is beginning to deteriorate.

* “Air box” (filter) replacement –DIY 3

Checking (and replacing, if need be) your engine’s air filter is still more or less the same as it was 30 or 40 years ago. The difference is getting at the filter. In the past, there was (typically) a round housing with a lid held in place by a wingnut. You spun loose the wingnut, removed the round lid – and removed the also-round air filter. Easy. It still is today – only now there is (typically) a box held in place with snaps or large plastic screws – and the filter inside is flat. It can look intimidating – but it’s not. In most late-model cars, the snaps can be undone without any tools – and if there are plastic (or similar) screws, these are usually easy to turn out with a basic screwdriver. You should not need more than that in the way of tools. So, undo the snaps – or back out the screws – and pull off the top. Now you can pull out the filter. If it’s obviously dirty, it probably should be replaced. If it’s not so obvious, you can try holding it up to a bright light (or sunlight). If you can see light through the filter, it is probably still ok. If you’re in doubt, lean toward chucking and replacing. Air filters are cheap. A dirty one that strangles your engine – or lets it suck in abrasive particles – can lead to expensive problems. Typically, a filter is good for about three years/30,000 miles – though this varies depending on such things as whether you drive down dusty roads a lot (more frequent filter changes) and so on. It’s a good idea to check once a year, regardless.

* Recharge the AC –DIY 4

The AC system in your car operates by cycling refrigerant (in most new and late-model cars, the compound is R134a) through a liquid and then gaseous state, over and over. And over time, as the system ages, some of this refrigerant (at the molecular level) escapes past seals and even permeates through rubber hoses. As the refrigerant level falls below what it should be, the system doesn’t work as efficiently – it doesn’t cool as well – and may even not cool at all. Sometimes, you can recharge the system yourself – and save a bunch of money. Most auto parts stores sell DIY recharge kits, which consist of a can of refrigerant with (ideally) a gauge and a hose to connect the thing to your car’s AC lines. There is a high pressure and a low pressure side. You want the low pressure side (the kit’s instructions will explain how to pick the right one). You connect the hose to the AC low pressure line, then start the car’s engine and cycle the AC system on. Now, you’ll press the button on the can of refrigerant – it operates like an aerosol can – while watching the gauge on top, which will have a yellow (low charge), green or blue (proper charge) and red (overcharge) face with a needle pointing to – hopefully – yellow and moving to green/blue as you recharge the system. Be careful not to let the needle pass into the red (overcharged) zone or you might damage the AC system. These kits really are idiot-proof, so don’t be intimidated. If your AC system is otherwise ok and merely has a small leak issue, you may be able to restore normal operation for $20 or so  (the cost of a recharge kit) vs. $100 or more to have a shop do more or less the same thing.

* Oxygen sensor –DIY 6

You may have noticed a plug-in looking thing with an electrical pigtail connection on your exhaust manifold(s). This is the oxygen (or O2) sensor. It sniffs the exhaust stream, relaying information back to the computer in order to maintain the ideal air-fuel ratio, which is important for gas mileage and critical for emissions control. Often, when the “check engine” light comes on, it is due to a problem with the O2 sensor. The way to know for sure is to have someone with an OBD scan tool “pull” the trouble code(s) from the car’s computer. Some parts store chains – for example, Advance Auto – will do this for you for free. If the OBD reader indicates a problem with the 02 sensor(s), you can DIY replace  this part yourself. Most just screw in. If the O2 sensor is readily accessible, you might try doing it yourself. Unplug the pigtail and – using a wrench or socket of the right size (there are special sockets designed just for 02 sensor removal) carefully remove – and replace.  Don’t forget: The trouble code will have to be cleared to get the “check engine” light to go off.  The OBD scan tool can do this.

 * Replace cabin filter –DIY 7

What started out as a high-end feature found only in high-end cars is now a commonplace feature in most new cars, even economy cars. These little jewels filter out particulates, pollen and so on – which can be a great help for people with allergies. But like the engine air filter, the filters don’t last forever. As a general rule, they need to be replaced about every three years or so. This is – usually – a very simple, DIY-friendly job. Your vehicle’s owner’s manual should have detailed instructions, but typically, what’s involved is finding and removing a small access panel that’s most often located somewhere in/around the windshield/cowl area, the front passenger side footwell area or “kick panel.” Pop the old filter out, pop the new one in. You can buy a new filter at your dealer – or an auto parts store.

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  1. Another good DIY article, Eric. I’m constantly teaching people just how easy it is to maintain their own vehicles. Doing it yourself also helps you avoid trips to repair shops and dealerships that want to desperately sell you every flush that BG provides.

    A couple of tips I’d like to add if you don’t mind. On the o2 sensor: generally they are a 22mm, or a 7/8 sized which is really just about the same measurment. Just a point of information for anyone reading this who wants to attempt an o2 replacement, but doesn’t know what socket or wrench to use. Also, looking at the specific o2 fault can help you decide when to replace the faulty sensor if money is tight. O2 sensors have heating elements built into them to bring the sensor up to operating temperature faster. Think of it like a heating blanket for yourself. The goal of the o2 heater element is to get the fuel system into “closed loop” faster. In closed loop operation, the o2 sensor takes over, and the engine computer no longer relies on base fuel maps. If one “pulls” an o2 heater code(P0154 for instance), one should not worry too much about this code immediately. Generally, the fuel system will still go into closed loop operation even if the heater is bad. It will just take a few minutes longer. The exhaust will still heat the o2 sensor. So, if you don’t mind the CEL on you can forgo that repair until you feel comfortable shelling out the dough for a new o2 sensor. The downfall here is that if you have another engine fault you will not know, because the CEL is already illuminated. It’s also good to know what sensor is bad, the “front o2” or the “rear o2”. On many vehicles, the rear o2 is only used for catalyst monitoring, and is only rarely used for fuel adjustments. However, this is no longer the case on most newer vehicles. Catalyst efficiency has taken a front seat in fuel mapping.

    If the sensor is stuck in the exhaust DON’T srtip it out, or round it off. This will make your repair more costly when you have to take it somewhere to have the sensor removed. I’ve had to use the torch to take out many stuck o2 sensors.

    On the pollen, or in-car air filter: they are amazingly easy to replace in just about any newer model vehicle. If you live in the country, or park your vehicle in the garage, I’d advise you to check the filter at least every couple of months. Rodents love to make their nests in and around the pollen filter housing. Which means that when the HVAC blower motor is switched on, you’re breathing in rodent excrement; gross! If you see a nest, take a shop vac, and remove the nest. Use a mask when doing this. After the pollen filter is replaced, switch the HVAC system to “fresh air” mode, turn the blower motor on high, and use a can of lysol to clean the system. Spray the lysol onto the cowl, and the blower motor will suck the lysol into the HVAC system. This may seem like a trivial point, but I’ve been turning wrenches a long time, and I see rodent infestations at least once a week.

    If you park your vehicle in the garage, do not keep your garbage or your pet food close to your vehicle. Rodents like to grab a bite to eat, and climb right up into your nice warm car!

  2. 1. You cannot put R134 in older cars. And there are no kits for R12. R12 can run $65-$100 a pound and $200 to have a mechanic put it in. This is thanks to the EPA. At one time you could by R12 at Wal-Mart on sale for $.99 a pound. And a recharge kit for $10.

    2. 90% of the time 02 sensors are clogged. A free repair is to remove the sensor, soak in gasoline for 24 hours, air dry it and put it back in.

    • R134a indeed can be used in R12 systems. Conversion kits exist and are often little more than adapters and decals. (beyond the R134a of course) R134a works acceptably in an R12 system. Perhaps not as well, but acceptably.

      • To do it right you also need to flush the oil. The oils are incompatible over time.

        Another option is to use Duracool or other hydrocarbon refrigerants (anhydrous mixture of butane and propane). Functionally these work better than freons, are compatible with all oils and do not corrode the metal components. Of course they are flammable so it depends on if this bothers you or not.

  3. I do all of my own work–have done so since teen-age years. A back up car is an excellent idea. I have had one ever since.
    Obtain a set of factory shop manuals. They can be worth their weight in gold as they will have specific instructions on disassembly / assembly order and have proven to be invaluable.
    Chilton and Haynes manuals are fine, but do not go into detail the way the factory manuals do.

  4. Just my .02, they went with a sixties design “cartridge” style oil filter for the Prius, along with a ratchet release and turn, non-standard filter-flute size, all secured under a plastic panel underneath with those damnable polystyrene push plugs to close it – within a year mine needed a repair, and I eventually just took that section off after it fell down and drug on the road.
    All to make it more daunting for the “shade tree mechanic,” and sell 110 dollar oil changes! I think they make most of the dealer profit in their rip-off “service” depts!

  5. I saw a jetcopter engine compartment open once. Beautiful stainless steel hose fittings. Everything designed to be both reliable and serviceable.

  6. Is there any blog, magazine, etc. that rates new and/or used cars on their user serviceability? I don’t have much of a problem with new car technology. But I do have a problem with new car engine component layout and the like, or which models require proprietary custom tools, etc.

  7. Who’s stupid idea was it to put those dumb clips to hold the bulbs for the headlamps in cars? My Nissan Altima has those. What should have been a simple twist was a royal PITA.

    • You’ll see that the newer headlight bulbs are indexed so they can only be installed one way. Most newer vehicles use the style bulb you’re talking about. They’re not too bad once you get the hang of ’em.

  8. I just finished my wife’s timing belt (’05 Accord)
    I’ve now done 8 timing belts, two of which were on diesels.
    Anyone can do this, the hardest part is acquiring the numerous specialty tools to make it easier.
    I’ve probably saved 15 grand in the last 20 years doing T-belts, wheel bearings & CV joints myself.

  9. My 2000 Honda Civic is a good car, but horribly inaccessible for replacing common items such as oil filters and alternators. Front wheel drive complicates everything else; I’ll take replacing a water pump on my old slant 6 to any such pump on a FWD any day.

    • Hi Ross,

      I’ve found some to be better – in some cases – much better – than others. Current Subarus, for instance, have their oil filters mounted in such a way that all you have to is slide under the front of the car and put a filter wrench on. The filter is “right there” – and Subaru thoughtfully left the area around it open and accessible.

      Meanwhile, my Frontier pick-up pretty much forces you to jack the front end up enough that you can reach through the passenger side fenderwell to get at the filter, which is mounted on the side of the engine. It’s still not directly accessible, either. You have to slip your filter wrench (cup style) around the metal power steering lines, which are in line with the filter, just ahead of it. Then, you slip a “wobble” extender bar through/to the side of the metal power steering lines and now you can loosen the filter. Once the tension is released, you can turn it out by hand. The new one can be started/tightened by hand. It’s not hard, once you know the procedure – but a Subaru is much easier!

      One of the worst I’ve dealt with in recent years was an older (’90s) Cadillac with the Northstar V-8. The filter is mounted upside down on top of the engine, with brackets and wires making it almost impossible to get a hand on it (much less a tool) without taking things apart.

  10. A lot of step-by-step DIY maintenance videos can be found on YouTube. None of this car stuff is really that difficult but most people are afraid of DIY. The videos on YouTube can help alleviate the anxiety. My friend did a timing belt change on a Subaru using “YouTube skills” and on-line parts stores with cheap OEM parts. The Subaru Stealership wanted $1400.

    • Hi Tony,

      That’s very true! I think – my theory – that DIY has become less common because the “fix it” attitude receded (generally) during the ’80s and ’90s. People who grew up with parents who were not “fix it” types tended to not become “fix it” types themselves. Previous generations of Americans were also – in general – more self reliant in attitude, which inevitably resulted in their being more capable.

      Just as one can self-educate by reading widely, one can learn to be a decent wrench by wrenching!

      • Not to mention the huge resource that the web is nowadays. I would have killed to have some of the DIY videos available back in the day. It would have saved me a lot of headaches working on cars and making stupid mistakes.

        I recently installed a new stereo in my new car, a process which took less than an hour and didn’t get charged the $80 install fee the local installer wanted to charge. I used a video from youtube to do the install.

    • $1400 is definitely on the heavy side for a Subaru timing belt service. Generally, anything over $1000 is too much for just about any timing belt. There are exceptions like the NSX, or the old Dodge Neon. I hate that timing belt! Watching YouTube videos, in my opinion, can help with the procedure, but I doubt it helps alleviate any anxiety. Especially for anyone who’s never been inside of a front timing cover. It can be overwhelming. Even getting the belt one tooth off can set timing phase codes, which means you’ll be right back in there re-doing the job. Or worse, having a cam skip, or something that would throw the timing more than a couple of teeth off can lead to catastrophic failure. On Subarus, which are interference engines, this is especially true. Pulling the heads off of a horizontally opposed engine is not a fun job.

  11. Good article Eric, few people realize that many car projects can be DIY with a little effort and research.

    I need to replace the fuel selector valve on my 1986 F250 and then do a tuneup and old style belts on it this weekend. That engine compartment on that thing is so packed I dread doing anything on it. I would actually prefer to work on my 2010 Corolla bUt at least I’m not paying a shop 500+ dollars to do it.

    • Thanks, Tom!

      I hear you on the dread of dealing with the “snake’s nest” (and tight packaging) under the hood of a modern car. My solution is to have a back-up car. A car you can drive while you fix the other one. Not being in any rush – being patient – is the key. People often get themselves into trouble by starting a repair job Sunday afternoon on a car that they need for getting to work Monday morning. Never do this unless you are extremely confident that whatever the job is, it’s one you have everything you’ll need – including the skill/knowledge – to finish in time.

      If you don’t have to be finished tomorrow (or the next day) it’s no big deal if you get stuck mid-way through by something you don’t quite understand…. or by a bolt head that snaps off!

  12. I’d like to like the Miatas, but for their inability to accommodate, comfortably or otherwise, anyone over 5’9″ or so. But at least they’re cute in a New Beetle sort of way.

    • Hi James,

      I’m 6 ft 3 and 210. I fit ok in the Miata.

      Years ago, I did a tour of GM’s “ergonomic” labs – where they have a variety of anthropomorphic dummies. Some tall, some short. Some with long legs, others with shorter legs – and so on.

      There is an almost limitless variation of torso-to-leg ratios (and so on). The point being, people vary. What may be uncomfortable for you might be ok for me (and vice versa).

      This is why I never just go by the specs – legroom/headroom stats – but instead urge people to actually sit in and test drive the vehicle they’re considering (along with its competitors). Some cars you’d swear would never fit you turn out to be fine. While others – with lots of room (spec-wise) are nonetheless not comfortable… for you.

      • So very true. I was test driving the older model Scion xA years back in 2006 and it was one of the most enjoyable experiences I have ever had. It was fun, reminded me of my parents old Civic, and at the same time I was amazed that it had better leg room for the driver than I’d expected. No, it wasn’t incredible, but it certainly was respectable.

      • Hey Eric,
        I’m 6’3″, 220 and “all arms and legs”. I’m j-u-s-t able to shoehorn myself into the Miata’s driver seat (ditto with the final-gen Toyota MR-2 convertible), but I’m literally unable to sit up straight with the top raised. Driving the manual shift was functionally impossible, insomuch that I didn’t have enough room to comfortably and properly lift my left leg to operate the clutch. No joke.

        As you say, we won’t know until we try for ourselves. I tried. It didn’t work. And I’m really fond of those little drop head coupes. 🙁

        • Hi James!

          Yup… it all depends on you. I’m close to your size (same height, weigh a little less) but the Miata’s ok for me. One that’s not ok is an original AC Cobra. I once had an opportunity to drive one – and barely could. How the hell Shelby fit his 6 ft 5 self in that thing is a feat that continues to amaze and astonish me!

          • Exactly right. It seems to depend on leg length vs. upper-body height. I’m 5-11, but when I test drove a Miata with the top down, I discovered I had to look over the windshield. Didn’t seem too safe in a rollover….

      • I’m 6.4″ and 275 lbs….the miata fits just fine on my left foot but I need another for the right foot. Thanks, but I’ll stick to my 2500 HD diesel pu for my fat a$$ body.

        • Hi Eric,

          When you’re a big guy, your options are somewhat limited! Sports cars are – usually – out for someone your size. I’m not far behind you – and these cars are often tight for me.

          It’s the same with motorcycles – if you ride, I’m not telling you anything you don’t already know. Someone your size probably can’t ride a Japanese sport bike without torturing himself. But a big Harley is perfect!

  13. Let me speak a word of praise for the air filter box in my 99 Miata.

    I think it is just about as easy as the round metal filter boxes of old with the wingnut on top.

    You just undo two latches and lift the thing off. That’s it, no tools required. And there is plenty of room under there to work.

    I used to have a 90 Miata that required removing some screws to get at the the filter. This is better.

    Easy peasy.

    • Amen on the Miata, Darren – they are superb cars. A track-day car you can drive everyday – for the next 15 years… and which almost never asks for anything, and when it does, it’s usually either easy to fix or cheap to fix and often both at the same time!

  14. I’ve done all of the tasks highlighted in this article. They are easy peasey (even for a non-wrench), as Eric suggests.

    I will mention that I do miss the round metal air filter housings from the days of yore. The wing nuts never required a tool, thus making lid and filter removal an always-expedient task. They were always up top, centrally positioned, and never in too-close proximity to emission plumbing. Modern plastic air boxes are none of those things.

    By way of example, have a look at the engine bay of a 3rd generation Honda CR-V:
    The air box is buried deep under the black plastic lid that sits under the master cylinder reservoir. I’ve not yet loosened the air box clips without bloodying at least one knuckle. I know that Honda had to find room for a lot of stuff in a comparatively small space, but still…

    Engineers. I have a love/hate relationship with them.

  15. Thanks for this, I never knew that was the O2 sensor. Air filter change was the first thing I ever did under the hood, back in like, freshman year of high school.

    Is serpentine belt the same thing as a timing belt?

    • Hi Brandon,

      “Is serpentine belt the same thing as a timing belt?”

      A serpentine belt is just the modern iteration of the multiple drive belts that used to be common. But they both perform the same function – turning (and so, powering) the various engine accessories. The pulleys on each accessory (e.g., alternator, water pump, etc.) are spun by the belt, which is spun by the rotational force of the crank pulley (it’s usually the bigger one at the bottom) which is spinning because the crankshaft is turning, which is being turned by the up and down motion of the pistons inside the engine. If the belt snaps, the accessories are no longer powered – so you’d lose (for example) the power steering and AC – but the engine itself would continue to run normally. At least, until it overheated – because the water pump would also not be turning.

      The timing belt is what coordinates the internal motions of the engine – the crankshaft spins, and in turns spins the camshaft(s) which in turn open and close the valves that feed air/fuel to the engine and allow spent gasses to escape. Everything has to be timed precisely and it is the timing belt that ties it all together, connecting the crankshaft to the camshaft(s) via the belt; the layout is similar to the external accessory drive layout – but if the timing belt breaks, the engine stops – in some cases, with catastrophic results. Usually, you’re just stuck. The fix is not technically complex (usually) but it does require disassembling most of the front of the engine – as well as some skill and special tools. It’s definitely not a job you can do by the side of the road with a screwdriver!

  16. Back in the 70’s, without all the anti-pollution stuff it was possible to sit inside the engine bay and work on the car. It was all to simple.

    Bikes are going the same way. It’s harder to fit big German hands inside a newer bike simply to get at things.

    Routine maintenance isn’t difficult, but for anything a bit deeper the amount of crap that needs to come off first makes for headaches. Some manufacturers have reduced the underbonnet impedimenta but it was especially bad in the 90’s.


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