Engine smoother after oil change

I think it's the same reason its best to have clean oil before getting emission tested. Contaminants in the dirty oil and crankcase vapors passing thru the PCV system to be re-burned then sensed by O2 sensors and the fuel mix is adjusted accordingly. I have experienced the same with my engines and has nothing to do with the brand or weight of the oil used.
I've never thought of it that way. Huh.
 
About 20 years ago, our family car was a GM with a 3800. Pretty sure it was the Series 1.

I left the car with my Uncle to check out levels, etc. We used to have the resources to do this. Early 2000s.

I got the car back.. I said Uncle! Wow! What spark plugs did you put in! Are these the AC Delcos? You said don't use Bosch on an American car, it runs GREAT! Wow! (I really thought he tuned up the whole car.)

He looked at me like I was crazy, and said, All I did was change the oil.
 
I was getting my oil changed at a dealership & I kept smelling a burning oil smell after oil change, my engine was also idling quite roughly, they use Ac Delco 5w30 full synthetic, I decided to change my own oil to save money & I bought Castrol GTX 5w30 full synthetic & an stp oil filter the car has ran smoother ever since it doesn't idle rough anymore either, I'm not sure what the problem was, but in my effort to save some money I have a car that runs a lot better, I drive a Chevy HHR with around 255000 miles on it.
 
I was getting my oil changed at a dealership & I kept smelling a burning oil smell after oil change, my engine was also idling quite roughly, they use Ac Delco 5w30 full synthetic, I decided to change my own oil to save money & I bought Castrol GTX 5w30 full synthetic & an stp oil filter the car has ran smoother ever since it doesn't idle rough anymore either, I'm not sure what the problem was, but in my effort to save some money I have a car that runs a lot better, I drive a Chevy HHR with around 255000 miles on it.
Lets see you went from a stealership $130 + oil change to around an under $40?
 
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I was getting my oil changed at a dealership & I kept smelling a burning oil smell after oil change, my engine was also idling quite roughly, they use Ac Delco 5w30 full synthetic, I decided to change my own oil to save money & I bought Castrol GTX 5w30 full synthetic & an stp oil filter the car has ran smoother ever since it doesn't idle rough anymore either, I'm not sure what the problem was, but in my effort to save some money I have a car that runs a lot better, I drive a Chevy HHR with around 255000 miles on it.
I wonder if the tech got sloppy and spilled oil on the engine when he'd change it, hence the smell of burning oil.
 
I was getting my oil changed at a dealership & I kept smelling a burning oil smell after oil change, my engine was also idling quite roughly, they use Ac Delco 5w30 full synthetic, I decided to change my own oil to save money & I bought Castrol GTX 5w30 full synthetic & an stp oil filter the car has ran smoother ever since it doesn't idle rough anymore either, I'm not sure what the problem was, but in my effort to save some money I have a car that runs a lot better, I drive a Chevy HHR with around 255000 miles on it.

I had the same problem after my last dealer change. It was running rough and there was even goo on the dipstick.

Not sure what they did. Maybe they didn't completely drain the old oil?
 
Anecdotally, there were guys who polished and waxed airplanes during WWII trying to get that little extra edge in speed. Did it work? I don't know, I wasn't born yet. :ROFLMAO:
Steve McQueen took his tank engine apart to attempt to hot rod/speed it up and then he could not get it to run anymore! LOL
 
I wonder if the tech got sloppy and spilled oil on the engine when he'd change it, hence the smell of burning oil.
I'm not sure on the burning smell, but with the results I got from changing it myself I think I'll be doing it myself from here on out, I've been checking it periodically & all is good, plus no burning oil smell.
 
I had the same problem after my last dealer change. It was running rough and there was even goo on the dipstick.

Not sure what they did. Maybe they didn't completely drain the old oil?
It's a possibility, unfortunately in this world honesty is a rare find these days, personally I'm choosing to do my own oil changes for now on, I'm not in a position to buy a new car right now, so I prefer to be on the safe side.
 
The only oil with which i can say i have really noticed an improvement in smoothness almost right away would be Valvoline Maxlife 10W-40, really liked that oil, sadly it's gone up in price a lot, used to be 28€ /5L where i bought it, now 40€/ 5L jug 🙁 making it almost twice as expensive as all the other A3/B4 10W-40s.
 
I'm not sure on the burning smell, but with the results I got from changing it myself I think I'll be doing it myself from here on out, I've been checking it periodically & all is good, plus no burning oil smell.


One big advantage of doing it yourself is that you become more familiar with the vehicle. Check things out underneath. Check all your fluids. Check your tires including the spare if you have one.

Anyone else doing it is concentrating on getting you in and out quickly. All that other stuff is ignored.
 
Steve McQueen took his tank engine apart to attempt to hot rod/speed it up and then he could not get it to run anymore! LOL
Steve McQueen's Military Occupational Specialty (MOS) was Tank Engine Mechanic. A tank didn't stay out of service waiting for a rebuild or for the TC to hotrod it. The story is a myth.
 
Yes it's possible.
Since viscosity and other properties between the 2 brands of oil plus old vs new fresh oil can make up the difference.
I also think it depends on how "connected" you are to your car and how well you are sensitive to how it feels and drives.
Every car I have acquired was used and clearly feel they get smoother over time with my care and my DIY work on them, notably oil changes. I guess all my cars' previous owners do not believe there's a difference after oil changes.
 
Steve McQueen's Military Occupational Specialty (MOS) was Tank Engine Mechanic. A tank didn't stay out of service waiting for a rebuild or for the TC to hotrod it. The story is a myth.
The story (myth?) may in fact be one. Yet it has been in books and videos about his life for many years. It is also stated that many of the things he got away with , not due to any fame (he was virtually an unknown-nobody) in the Marines (1947-1950) would get you kicked out today ASAP with a speedy dishonorable discharge. He was also under age and his mother had to sign for him to be allowed to join. They mentioned how young , innocent and child like he looked may be the reason he was cut so much slack in those military years. He opted out of the Marines and headed for a new life just months before his entire tank squad was completely wiped out in the beginings of the Korean war.
 
"I went to a mechanic shop and fixed my car and feel it runs better now", says the car owner. His friend said "likely placebo, just because you went to a mechanic doesn't mean your car is fixed".
 
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