I've had mechanics tell me my cabin filter is bad on a vehicle that didn't have one.
I've had mechanics show me how gross my spark plugs were in a diesel engine sedan.
I've had mechanics tell me I need new tires on a truck I had just replaced the tires on two weeks beforehand, and driven in mud.
I know more about my truck's issues than the guy who just did an oil change and casually glanced at a couple other things.
All that said, I still appreciate an actual mechanic (not the lube guy who started on Tuesday) telling me what they found wrong. You ever know when you might actually miss something.
Those are shit mechanics who are just trying to steal as much money as they can. I would avoid them and call them out whenever possible. I've had some good mechanics who go out of their way to save you time and some who have actually helped without charging extra. Not to say it's required but the stigma of bad mechanics has ended up being the way it is by having people oblivious to what happens under their car's hood.
Yeah, I don't go back to places like that, I leave reviews, and I tell anyone who mentions car trouble "don't go to this place here"
There's a shop about 35 minutes from me I've been at for awhile now, they've saved me quite a bit of money over the years and the ONLY time I've had an issue with something, THEY contacted ME to ask me to come back in so they could fix a mistake.
I had a diesel mechanic tell me that the diesel engine in my school bus needed new glow plugs. This was at least a more reasonable scam as diesels normally do have glow plugs, I just happened to know that my engine (a DT466e) doesn't have them.
To be fair, I've told someone spark plugs on a diesel after I changed a few on gas cars.
They have glow plugs. I knew what I was saying, but it was a long day.
They go in the boom holes and help with said booms. Don't look at me because I'm not an English major. When I order parts I point to the catalog and grunt like a caveman, because my brain is smarter than my mouth.
If you have a clogged air filter you will damage your engine. Most of the time slapping the air filter against your leg to get the dust out helps. If you see oil on it then there is a serious issue, that could have been from not changing your filter.
An old air filter will do one of two things. Make your engine run rough because it isn't getting enough oxygen, 1/3rd of what makes your car go forward. Or allowing dirt to get into your engine and that will 100% damage your engine. Imagine if you will, instead of lube you used grit soap. Please don't ruin your car over a $30 part. Filter is cheap, engines are expensive.
Change your own air filter. One of the easiest things you can do for maintenance. It's either clips or a size 8mm socket... usually. Then you don't have to pay some kid $100 for 2 minutes of labor. You'll feel better for doing something and you will also get better gas mileage. If the answer to when was the last time you changed your air filter is "I don't know" then it's probably time.
Air filters are such an easy part to replace it's insane. I pop that bitch out once in a while and slam that bitch against the wall. Also you should check you vacuum filter too since it's basically the same thing.
You change your own oil, but don't rotate your own tires? Changing tires seems like the easier of the two, especially if you already have everything to lift the car?
"Easy" in terms of complexity, yes. "Easy" in terms of strength required to mount and dismount wheels (especially the big heavy ones on the SUVs so many folks have these days), no.
Even my automotive engineer friend who can basically repair his whole car alone often pays for his oil changes because of the convenience of not dealing with old engine oil and its disposal
In most places you can drop off used oil at your local auto parts store for free. It's still super easy.
The only vehicle I don't change my own oil on is my truck, which has off-road skidplates you need to remove first. I could do it, but I decided it was better worth my time to have a shop do it.