Hi Theone....that sounds really odd. I assume that your owners manual specified 0-20? Darrell.

 

Unsure of why it may feel that way... But the interval is every 10,000miles for oil and filter change. The oil is supposed to be 0w-20 so does not sound like u did anything wrong

 

Could it be that I added a little over 4 quarts?

 

I guess you added the correct amt. of oil Theone, according to the owners' manual? Darrell.

 

Its very well possible that the oil isn't labeled correctly. I had a similar problem years ago. To make a long story short the oil I put in my car was noticeably darker and thicker as compared to what I have always used. The oil was the same brand and same weight but my car seemed somewhat sluggish and my mpg's dropped by 2 to 3 miles per gallon.

The next time I did an oil change I went to the store got the same oil and the oil was a much lighter color(just like it used to be) and was much thinner and mpg's went back to normal and the car wasn't sluggish.

I just know during that one oil change that it wasn't the right oil or it was formulated wrong.

 

Check your oil levels, to much oil will damage an engine as well.

 

I went ahead and changed the oil on my car at 15,000 miles and went with
Castrol Full Synthetic 0w20 on my 14" Corolla S with the CVT.

My car feels different now. The acceleration is not as responsive and the SPORT mode also lags to respond. Did I use the wrong oil weight? I used approximately 4.3 quarts and ever since then I noticed the car's acceleration change.

You used the correct oil and put in the correct amount if you also changed the filter so the oil is not the problem. My guess is this is all psychological unless you also have a big drop in MPG.

 

Yea, I tend to agree with what was said about all in your mind, you did everything right, and there is nothing wrong with the brand of oil you used or the amount.

 

Unless you used the wrong oil, I think you're just got a placebo effect going on.

 

Even if you put in 60 weight oil you wouldn't feel the difference. The only difference is you'll get decreased fuel economy at the benefit of increased wear protection.

 

I always use 5-40w in a group IV or V oil such as Amsoil or Redline for extra protection of valve train and rings. Manufactures went to 0-20w for increased gas mileage to meet CAFE standards, but it doesn't protect as well as a heavier weight oil. This is controversial, but I err on the side of heavier oil at the expense of gas mileage (which is probably not that significant).

 

No disrespect but today normally the lighter the oil the better protection. The only exceptions would be if the weight of the oil is so light that it breaks down under excessive heat, pressure, or some contaminate and the synthetic oil will not do that in a normal personal vehicle.


Think of it this way. I will exaggerate to make the point. Take a can of STP and a can of 0w-20 synthetic. Cut 4 pieces of cardboard and put some STP on two of them and 0w-20 on the other two. Now rub the 0w-20 pieces together and then rub the two STP pieces together and see which one is harder to slide.


Of course the 0-20 is easier because there is less friction. The same principle applies in an engine. As long as the oil is not too hot and losing its ability to protect the thinner the better.


The 0w-20 synthetic is good for up to 400 degree "F" and down to -50 degree "F" with protection.


In your case using 5w-40 you are actually doing harm to your engine especially at start up when the oil is not pumping yet and is cold.


5w-40 synthetic is only good to about -30. That means on cold start up regardless of temperature the oil is thicker than it should be and it does not protect as good as an 0w would. So in the end you are losing MPG and causing added wear to your engine by using 5w-40. So thicker is NOT better in your case or most any other drivers case. Now on the race track under extreme pressures and heat it would be different. You would go for a higher viscosity for wear protection due to heat and pressure and not worry about the loss of MPG.

By the way, the first number is the winter protection number. The "W" denotes winter. The second number is the summer protection number and does not mean higher protects better. Only that it will hold up under higher temperatures and pressures. The thinner the oil the better the protection as long as it is not breaking down and I assure you your oil is not getting 400 degrees so you absolutely do NOT want 40 weight summer oil.


I strongly suggest that you run what the manufacturer calls for.


Here is a link with some explanation.
http://www.toyota-4runner.org/gener...r.org/general-discussions/68847-why-0w-20-synthetic-oil-explanation-inside.html

 

^^ I agree with saved, heavier oil doesn't mean better protection at all. Most wear happens at cold startup and 20 weight oil flows faster, sooner and better in a cold engine than any thicker oil.

 

Just look at the viscosity index at cold and hot temps. At cold temps it can't be thin enough and at hot temps it can't be thick enough. Ideally you'd run a 0W-60 but that's $$$ so high end cars use the cheaper 10W-60 oil.

 

A 0w in a 0w60 is not the same as the 0w in a 0w20. The 0w doesn't stand for a weight seeing there is no such thing as a 0 weight oil....

 

It is a little more complicated than that. The term "weight" is not a really good designation for the first number or even the second with multi viscosity oil. Also yes there is "0" viscosity oil, it is just tested differently to come up with that designation. And finally yes "0w" is "0w" regardless what number follows.


Here is a couple links that gives some good information. One is a little deep and the other no so much. I hope this helps. :smile:
http://www.carbibles.com/viscosity.html
http://www.upmpg.com/tech_articles/motoroil_viscosity/

 

Nah, I have studied oils for close to 8 years and if anyone wants to get enlightened on true information directly from industry insiders and lab technicians, please head over here:


http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm


Everything can be confirmed there. No offense intended, but I am not going to get into an argument with someone that states a 0w60 and a 0w20 are the same viscosity at -20c.


BTW, they have tested that the 0w20 we get from the Toyota dealer is amongst the best in the industry! Almost no wear at all!

 

BTW, they have tested that the 0w20 we get from the Toyota dealer is amongst the best in the industry! Almost no wear at all!

That's because it's thicker than other 0W-20 oils. So unless you're buying Toyota's oil get something thicker if you want wear protection.

 

 

A couple of quick notes:

1) Anything below operating temp is considered "cold". If you live in sub freezing temps where oil doesn't flow then a synthetic 0W-xx maybe helpful.

2) Wear doesn't happen during startup, it happens during warmup. Thick oil doesn't cause wear, thin oil does. During warmup when the viscosity drops is the increased the chance of wear. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3482440/Castrol_engineers_talk_on_star

 

A couple of quick notes:

1) Anything below operating temp is considered "cold". If you live in sub freezing temps where oil doesn't flow then a synthetic 0W-xx maybe helpful.

2) Wear doesn't happen during startup, it happens during warmup. Thick oil doesn't cause wear, thin oil does. During warmup when the viscosity drops is the increased the chance of wear. http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3482440/Castrol_engineers_talk_on_star

There are several hundreds used oil analysis reports which completely refute your claim. Lab results can't be argued.


Thick oil in cold conditions resists flow which means vital components gets oil flow slower than with a thinner supported oil for a given engine.