Changing Oil Brands Oddity ?

Status
Not open for further replies.
Joined
Sep 10, 2010
Messages
3,806
Location
PNW
In my last oil change I ran Valvoline Advanced 5W30 (no issues) before changing oil out to QSUD 5W20 ... Surprisingly , for the first couple of days the engine ran slightly rough and the gas mileage actually dropped before smoothing out and the gas mileage improved . Is there any truth to the belief that this happened as a result of the new oil needing a little time to remove the old add pack on metal surfaces before laying down it's own new add pack on metal surfaces and smoothing out ?
 
I've moved back & forth between the two grades just as you did. In fact, I've use the same oil brands & weights just as you did, going from one to the other in the same order you did. However if anything, I noticed a smoother/quieter engine with the QSUD.
 
Last edited:
It's more likely that the gas you used had changed in some way. However, what you experienced has been noted before and could have something to do with the change in additive systems, although unlikely.
 
Originally Posted by alarmguy
No truth, your engine roughness had nothing to do with the oil change/brands.



Incorrect. Flat Earther !
smile.gif


The add pack changeover effect has been discussed for decades.

I though my VW was going to blow up it ran so bad after an OC.
Going from a Ti DP oil to a different package had a similar
"engine is about to blow" effect.

It's that bad sometimes.

ChrisD46 you should have stuck with the Valvoline advanced. Best stuff out there right now in 5W30
 
Last edited:
I highly doubt changing oil brands or weights had anything to do with engine running rough. If that was the case "almost every" car would go through this rough running engine phase.
I think gasoline or possibly MAP/MAF sensor got a piece of dirt on it.
On the very, very, very outside.........0001%, maybe, maybe going to "thinner" oil did not let 1 or more hydraulic lifter pump up for some reason.
Either that or car was mad
mad.gif
about getting QSUD 5W20 and wanted it's Valvoline blood back, because Halloween is coming..................
shocked2.gif
 
Originally Posted by JohnnyJohnson
I change weights and oil almost every OCI and its never been an issue in the 15 years + I've owned the Corolla.


Me too, never noticed any difference after the initial psychological effect of feeling smoother just 'cause new oil is in there.
 
Originally Posted by ARCOgraphite
I stand by my observations over 70 cars and 100's of oil changes.

I'm just a sensitive guy
smile.gif



You may be right, i just never noticed...
smile.gif
 
I've never seen any sort of change in the engine when changing oils.

I once had a headlight go out right after changing the oil though.
 
Originally Posted by ARCOgraphite
I stand by my observations over 70 cars and 100's of oil changes.

I'm just a sensitive guy
smile.gif



I believe you. With that many oil changes on many cars and being in tune with the engine, you're likely bound to hear some differences. There was once a member on here that used to work for XOM and he described it as "seating". Now, I'm sure this only happens in a smaller percentage of cases, but I can see it being totally legit. Especially if you're maybe changing from one oil with a very unique and different chemistry to another.
 
I've noticed some oils make the engine quieter, but never experienced rough running from switching brands.
 
I change oil mfg all the time and sometimes even grade, albeit less often than I do change mfgs... and I've never noticed an appreciable difference in mpg's. What I do notice when it comes to mpg's is my occasional lead foot!...‚

However, some lube brands do seem to produce more "noise" in my valve train for the first few hundred miles but it almost always settles down...I say "seems" because I have no real scientific way to substantiate that other than my calibrated ear and having sat behind the steering wheel for all 164k+ miles on my vehicle....‚
 
Last edited:
*It wasn't a huge difference but noticeable I believe - then like I said after a day or two the QSUD settled in and appeared to run smoother like I thought it should ... Probably just a placebo brain cramp .
 
Status
Not open for further replies.
Back
Top