Ten Common But EXPENSIVE Mistakes DIY Mechanics Make

Here at Budget Mechanic we love doing our own car repairs because it saves us a ton of money. But there are some mistakes you can make that will turn a DIY car repair job that's meant to save you money into a repair bill that costs way more than the shop would have charged you in the first place. Unfortunately over my 20 years of working on cars I've seen people make these mistakes way more than you think. So today we're counting down the 10 most common DIY repair mistakes working our way down to the one I see more than any other. Let's go. Now number 10 involves these guys. Dirty shop rags. Now when you're working on your engine you're going to have some rags right? And as you know things get a little busy a little disorganized. You've got tools up there by the windshield. You've got fire stuck in the frame here. The mistake comes when you leave rags in the engine compartment. So you may be thinking what's the big deal with a couple dirty rags? Well let me tell you. Rags are a whole lot lighter than all the other tools that you've got laying around and I have seen it so often where they will actually get sucked into parts of the engine. Usually when stuff has to do with air moving. An example of this could be if you left the rag here and started up the engine you have a big cooling fan on the front of your engine which could suck this big old rag inside and chances are this rag is going to stop that fan suddenly from turning and you run the risk of actually breaking the fan. And replacing a cooling fan can easily be around $500 just from a little rag. Even worse if the hood was closed when this happened or you didn't notice that the rag was in the fan your fan could not be running you could overheat your engine below your head gasket. Now it's a super expensive mistake. Another couple examples include belts and pulleys. So if the corner of the rag gets caught in your serpentine belt and gets dragged all through there it's going to cause a ton of damage. Another example is if your car has a turbo. Those things are like little high velocity vacuum cleaners and they can suck a rag from across the engine compartment straight into that turbo. It's probably going to explode it or break it and pieces of that can go into your engine. One other thing that can happen is if you've got a hot engine and you have a rag which are often soaked in oil or grease laying on a hot exhaust part can actually get them to catch on fire. Getting a fire in your engine compartment is something you want to avoid. So like I said this sounds really simple but it's way more common than you think and you can end up causing hundreds of dollars of damage all the way up to potentially an engine rebuild just from a dumb little rag. So if you're like me and you like having rags around when you're working on your car just make sure that before you turn the key and turn the engine on you don't have any rag anywhere near your engine. Now this next mistake is pretty common amongst DIY mechanics because it's not as obvious and that is when you're working on your suspension elements and you tighten everything up when they're not under load like when it's up on a jack. When a car is just sitting on the ground normally the suspension is in what I call a neutral state which means it can go up some and down some depending on what bumps are going over. This is not in a neutral state because it's up on a jack so everything has drooped down when the car is lifted it's at the maximum extent of its travel which is all fine and good if you're working on suspension and replacing parts. The mistake people make though is tightening everything up when the suspension is at its maximum position here then when the car gets lowered back down it puts a ton of extra strain on certain suspension elements and they wear out a lot faster. It's like if you were putting a belt on in the morning and you sucked your gut way in and set the belt it's going to feel really tight the rest of the day. Now the reason this happens and what a lot of people don't know is that certain parts of your suspension particularly bushings that are made out of rubber they can't actually spin indefinitely they have a range of motion so that's why it's important that you set them and lock them in place at that neutral state. So real common ones are lower or upper control arm bushings sway bar bushings some lower shock mounts have that rubber bushings there's other parts. So in addition to having to replace your suspension elements more often which can add up really fast improperly tightening suspension can also throw off your alignment which will wear out your tires more often those are really expensive. So if you're going to be doing your own suspension work especially on one of those bushings that I mentioned before you want to get everything hand tight put the wheel back on and set the car back down on the ground then do your final adjustment. Now the next one involves a tool that we all know and love but the mistake is using vice grips to work on your car. Now I get it vice grips are super handy and they grab really hard but a lot of people rely on them as some sort of a universal tool instead of taking the time to go grab the right socket for example you clamp on with one of these and start tearing things apart. This is especially true I found when people don't have the right big socket and they come across a nut they got to get off and they look at these and like oh those are big they'll fit around it I'll use this. If you think about it vice grips have really sharp teeth they work by sinking into the metal of whatever you're grabbing. If you use them they end up really damaging the nut or bolt that you're grabbing onto. I view vice grips as kind of an emergency last resort tool to get off something that's really stuck just because it's so damaging to whatever you clamp it to. So you don't want to use it on everyday maintenance projects. For example I've heard of a lot of people using vice grips as the way that they remove and install the drain plug on their oil pan which is crazy to me because if you do that enough you're going to remove enough material on that drain plug you're not going to be able to get it out or you're going to mess up the threads you're going to have oil leaks or worst case you're replacing the entire oil pan. Another common mistake that people make with vice grips is grabbing onto tubes or pipes so for example these brake lines here if you were to grab onto it to hold it so that you could crack a nut these are very easy to crush and these are very strong. So if you were to crush a brake line with vice grips that would be an expensive brake system fix. So vice grips should be used as an emergency last resort after you've already tried the proper tool on a fitting you can't get it out go ahead and use vice grips but once you get that nut or bolt or whatever it is off you want to throw that thing away don't try to reinstall it you want to replace it with a new part. Now the next mistake involves one of these guys involves these guys and no your video did not skip back to the beginning but bear with me I'll explain. Now there's a few common engine repairs that you can do as a DIYer to save money that actually open the internals of the engine up and expose them to the outside world. The mistake I see is not covering openings in the engine while working. One really common one is the valve cover you remove that to replace the valve cover gasket but it opens up the valve train it opens up coolant ports and oil ports and if anything gets dropped in there tools dirt debris I don't know what it can cause some serious damage if it blocks an oil passage and you end up blowing some kind of bearing you're looking at an engine rebuild. If you drop some little tool inside of a valve spring you could end up damaging that valve have to get a top end rebuild those are very expensive consequences for a little something falling into the top end. Another really common job that has to be done is the removal of the intake or the plenum and in a lot of cars when you remove that you're exposing directly down into the intake port intake valve so again anything that gets dropped in there has access directly down into the valves and the cylinders. I had one job I did many years ago where I actually dropped a socket I saw it go in and it took me an hour with a magnet trying to get that thing back up through the plenum but if I wouldn't have gotten it out it could have jammed in the valves broken that valve or it could have gotten into the cylinder and blown up my engine. Another example is if you're working on a fuel pump in the back seat of a car you open that sucker up and you're looking straight down to the fuel tank so anything that gets dropped goes right into your fuel tank. So this is where the rag is your friend anytime you're opening up the engine and it's exposing passageways upward or things can fall inside you want to get it covered up. Another thing I like to do is if there's a passageway I'll shove a rag down inside of it that way it plugs it and anything that sits on top will get pulled away with the rag when I remove it. The next mistake has to do with your brakes and it's one of the most important steps when doing a brake job and I see people skip it all the time and that mistake is not greasing your caliper slide pins. Now I find that people don't grease their caliper slide pins because they don't even know that's a thing to do or honestly because they're just being lazy. Now these slide pin bolts are what allows the caliper of the brake system to move back and forth for proper braking and they have to be greased and slippery to enable this motion right here. Now if the grease gets really old and sticky or goes away then your caliper can no longer slide and it introduces a whole bunch of expensive problems. So without good grease on the pins the caliper can't move and essentially holds the brake pads on the rotors constantly and that creates a whole bunch of heat and ruins the brake job that you just did. So you spent $300 buying brake parts you're gonna have to redo that brake job very soon with all the heat that it's creating. Because of that heat you're gonna ruin the brake fluid that's in that line and you're gonna have to do a brake fluid flush as well and probably more importantly your brakes are being held creating heat and not working properly so your car could start pulling to one side or you get brake fade and the car won't even stop properly and that's dangerous. When you're doing your brakes just make sure that when you're putting things back you properly clean and re-grease your slide pins. Now you don't want to just use any old grease you want to use a proper brake grease that can handle the high temperatures and just be aware on this car the slide pin is built into the caliper bolt and on others it's a piece you just want to find where it is and grease it. Now this next one let's be honest has all to do with being lazy and that mistake is not removing the parts of the engine that need to be moved in order to do the job. Now we're all guilty of this you know that when you're trying to do that one job you're supposed to remove the intake first or remove the battery so that you can get to the part instead of doing the job properly you skip to step number five and you try to yank the part out without clearing things out of the way. A really common example I see all the time is starters or alternators where you're supposed to remove the fan and radiator first to make room and people take the fan off but then they're like the radiator is really hard to get out so I'm just going to try to scrape this alternator past it and they end up puncturing the radiator and now they're $600 in the hole because they didn't want to take the radio out of the way. If you look at an engine there are all kinds of pretty fragile coolant lines vacuum lines plastic plugs that can be easily broken if you just leave them in the way of all the work that you're trying to do so if I was going to say replace this throttle body and I didn't clear things out of the way properly first I'm going to break something and that's going to make the job take way longer and cost a lot more money. So if you're going to do any job on your car don't be lazy take the time to remove the things that have to get out of the way in order to do the job right. Hey I hope you're enjoying this video if you're learning something or having as much fun as I am then make sure you subscribe to the channel as only 10% of you right now are actually subscribers and it's the best way to help us out. I know you know what this is and you should never use one when working on your car. Now of course I'm kidding but the mistake is using an impact for everything on your car. The problem is there's a ton of nuts and bolts on your car and some of them are made to crush washers to create seals some of them are made to stretch to create pressure and other ones are made to be tightened to a very specific tightness in order to keep things from leaking for example. Your impact doesn't know the difference. So a lot of people get under the hood and whatever job they're doing they use it with an impact. So for example if I was doing this valve cover I could easily find a socket that fits these bolts but I would most likely strip out those bolt holes. Now my valve cover can't be bolted down and I've got to somehow fix stripped out holes in the top of my engine. Another example is reinstalling that oil drain plug. Yes I have heard about people using their impacts for this. It's a big bolt sometimes but that's really thin metal. You could easily strip those threads out with an impact or you could cross thread it where it's all jammed up in there and you might not even know because this thing's so strong. Now you could be leaking oil everywhere which could destroy your engine or if you realize and have to fix it you could end up having to replace your oil. Now the biggest mistake that I see with an impact is on lug nuts. It usually leads to lug nuts being over tightened. The problem when you over tighten the lug nut is you generally start screwing up the threads on not only the lug nut but on the stud coming out of the hub and if that keeps happening eventually the lug nut will seize onto the stud and snap the stud off and that's a massive problem coming from just a simple operation of taking your wheel off and putting it back on. Now if you've seen any of my videos you know I do use an impact to put on lug nuts but it's very specific. I will start the lug nut by hand. I'll use the impact to spin it all the way snug so that I don't have to sit there with a wrench and spin each one 100 times but I don't use it to tighten the nut all the way because with your lug nuts and with pretty much every bolt on your car there's a specific torque setting that they should be tightened to to operate properly because lug nuts as well as most of the bolts on your car are meant to be tightened to a certain torque specification so a certain tightness in order to work properly. Now if you're not confident in doing that by hand you can use a torque wrench. So here's how to avoid expensive mistakes with an impact. Use it for removing bolts. It's great for that. Lastly if you're going to use an impact to put a bolt or nut on just use it to snug it up but always finish by hand or with a torque wrench. Now if you follow this channel at all you know I'm always harping about this because a huge mistake that I always see is people mishandling their battery. Now the biggest problem I see is people not disconnecting their battery before they do electrical work on the car. Common ones are when you're replacing your alternator or starter that have a big old positive lead going straight from the battery. So if you don't disconnect the battery before messing with that stuff you can touch something with your wrench and get a shower of sparks, tons of heat, worst case you can burn yourself or start a fire. Another example of a battery handling issue could be simply reversing the polarity on jumper cables or if you're installing the battery you put it in backwards and positive goes to negative and negative goes to positive that can really mess stuff up because you can actually blow out your ecu or different modules of your engine create really expensive electrical problems. But the biggest battery mistake I see is people improperly tightening their terminals. If you can reach under the hood and do this with your battery terminal it's way too loose. Doing that is going to cause a few problems. One, the battery probably isn't going to charge properly from the alternator. Probably going to stress the alternator out and you're going to have to replace that sooner than you would have had to and also it may just cause your car not to run. Next time you get in and try to start it up it's not going to run. It can also burn out relays and fuses which can make diagnostics in general really confusing. Here's the thing, proper battery handling is pretty simple. When you're ready to do some electrical work you disconnect the negative terminal on the battery that deactivates the electrical system. If you're reinstalling a battery or you're jump starting it you want to make sure the black goes on black and red goes on red. If you don't have something that's really clearly marking it there should be negative or positive marks on the plastic and if you don't see those another way you can check is that the negative terminal of a battery on the car side usually goes to the body and the hot side the positive side usually goes straight to a fuse box. Now when it comes time to put the terminal back on you want to make sure that this nut is nice and loose so that that terminal fits all the way down to the top of the battery. Sometimes I even hammer it down just to make sure then I tighten the nut that way it's a nice snug fit. Now this next one is often the first step in any car repair but if done wrong it can kill you and that mistake is improperly jacking up your car. Now whether you've got a bottle jack or a shop floor jack the main problem I see is where the jack gets placed. Now a lot of people put the jack under the side of the car in the middle of the frame where it's actually going to bend that pinch weld so the body of the car is actually going to get bent which if you choose to fix it is a big body repair very expensive. Another thing people often do without thinking is they stick the jack under the engine and start lifting and end up lifting on an oil pan or a transmission pan which is very thin metal and will often bend or crack and now you're leaking transmission fluid all over the place and you've got to replace that. Another thing people like to do is stick the jack on something that's not straight so maybe a control arm that's kind of angled and as they start to lift the jack slips out because it's on an angle and the car drops and if that happens while the wheel is off or you happen to be under the car it's going to be super expensive and or deadly. Now another mistake that I see that comes down to laziness is not using jack stands. If for some reason the wheel is off the car and it falls off the jack and you don't have a jack stand the car can actually fall back down breaking a lot of things underneath. The wheels off, rotors, calipers, oil pans, body panels, subframes, all things that are very expensive to replace and that's not even counting if you're underneath there getting cut. So just make really sure when you're jacking up your car to work on it you pick a good jack point so pick the reinforced spot underneath the body to lift on or use a straight flat frame point something that's really strong. Then when it comes to jack stands like I mentioned there's a trick to this. What you want to do is put the jack stand under the car and it'll lower the car gently onto the jack stand. So you can leave the jack there still holding the car but there needs to be some pressure on that jack stand so that it doesn't move. I had a friend that had a jack stand under a car and he's working on it and the jack let go but because the car wasn't sitting on top of the jack stand it shifted as it came down totally missed the jack stand and he almost got crushed. So just need to make sure that there's good contact there. And don't forget the wheel chocks. Don't be lazy and skip this step. Now this next one isn't what you'd expect but it gets people in a ton of trouble and it's the number one mistake I see among DIY mechanics and that is not properly documenting the repair. What do I mean by this? Well labeling your parts and taking good photos. Now one example of where this can bite you is say you're working on your ABS sensors or your brake lines and you get everything disconnected you can't remember how they go. You may put it back together in a way that looks right but the next time you go to turn right it rips out your brake line or your ABS sensor. Now you've got some really expensive problems. It could have been solved by taking a picture or your water pump for example. They often have different length bolts all around the flange. If you put a long bolt in a short hole and force it you could actually punch a hole in the side of your engine or a short bolt in a long hole you'll probably end up stripping those threads out. Another example is rear drum brakes. I've been working on these things for years and years and I still take pictures before I take them apart because there's so many parts all kinds of springs and if you get it wrong when you put them back together not only will the brake job take you way longer but you could actually end up risking having the brakes seize up which is a bad deal. Now the more in-depth the job gets the more trouble you can get in if you're not properly documenting the repair. One of the most serious examples of this is a timing belt or timing chain job. If you're not documenting and putting things back just the way that they're supposed to and you have say an interference engine you could start the engine up bend a valve break a piston and you're talking about a major engine rebuild. So with any job what you really want to do before you start working on it is take good pictures of how it looks that way you can put things back the way that they were. Now it can be annoying to do but you even want to do this as the job progresses and your hands are all greasy you want to try to get those photos as the job goes deeper you're really going to thank yourself later. When it comes to different bolts and where they go and which length goes where you want to put them back into the parts that you're removing so it's obvious where they go or put them in bags and label them or what I like to do is sometimes make little cardboard templates and push the bolts in the actual orientation that they're supposed to go. Some guys will even set up a video of them doing the whole job so that at any point they can rewind and see exactly how they took something. You just want anything at your disposal to give you a reference of how to put things. So again guys a little preparation taking your time to do it right could save you thousands of dollars of totally unneeded repairs. Now there's a lot more mistakes that DIY mechanics make than just these. In fact we made a video right here just on the mistakes that you can make during an oil change you're not going to miss that.