Engine MUCH Better with 10-40?

Messages
189
Location
NJ, USA
Hi, Before I start - I note immediately that I am not imagining things. I have a 4cyl 2005 Honda Accord Auto. I recently posted how I changed oil to 10W-40 (Castrol Syntec) due to the fact that I got some for free and that I was worried about using this thick oil in an engine that recommends 5W-20. Ok, here is the thing; the engine "pulls" much faster and better with 10-40. Also, it shifts into the next gear slightly "later" with this oil making the car feel faster of the mark. I drove a friend's Accord with 5W-20 back to back (also 05 4 cyl) and difference is amasing. Any comments? I do intend to switch to 5-30 after the next oil change or even back to 5-20 but I just might put 10W-30 (instead of 10-40). Comments?
 
Messages
7,409
Location
Austin, TX
quote:
Originally posted by Accord2005NJ: Also, it shifts into the next gear slightly "later" with this oil making the car feel faster of the mark.
That would indicate it's taking longer to reach the RPM shift point, thus, the car is taking longer to accelerate. This result agrees with virtually all dyno tests I've seen which shows less HP/Torque with thicker oils. But it's clear you've convinced yourself a long time ago that thicker oil is better for your car. Just use it if it makes you happy.
 
Messages
5,747
Location
North Texas
quote:
Originally posted by Accord2005NJ: Hi, Before I start - I note immediately that I am not imagining things. I have a 4cyl 2005 Honda Accord Auto. I recently posted how I changed oil to 10W-40 (Castrol Syntec) due to the fact that I got some for free and that I was worried about using this thick oil in an engine that recommends 5W-20. Ok, here is the thing; the engine "pulls" much faster and better with 10-40. Also, it shifts into the next gear slightly "later" with this oil making the car feel faster of the mark. I drove a friend's Accord with 5W-20 back to back (also 05 4 cyl) and difference is amasing. Any comments? I do intend to switch to 5-30 after the next oil change or even back to 5-20 but I just might put 10W-30 (instead of 10-40). Comments?
I used 15W50 once in my 97 Honda Civic when it required 5W30 and let me tell you that the starter didnt like that. It would take longer to turn over but two weeks later i traded my car in for my Tacoma.
 
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1,550
Location
North Texas
Syntec 10w40 is slightly thinner than regular old dino at the same viscosity, so thats why you are getting away with this experiment [Wink] At 210*F syntec is 70.9 which is about the same thickness as Havoline dino 10w30. At 100*C it is 13.2 which is slightly thinner than regular dino 10w40 at the same temp, but still thicker than 10w30. I would guess what you are feeling is slightly increased compression. I also guess once you've driven a few miles you will also notice the gas guage going down quicker than your friends car with 5w20. It's all a trade off, but if it were my car i'd be running 5w30 as that has proven itself time and time again in Hondas. In addition the 5w20's also seem to be proving themself as well. Try some syntec 5w30 and see how you like it. Or if you are a brew-master you can mix your 10w40 syntec with some 5w20 and get a 7w30. Instead of GermanCastrol, you will be making NewJerseyCastrol [Wink] Then again, i dont like to mix, i just doesnt feel right:P
 

Accord2005NJ

Thread starter
Messages
189
Location
NJ, USA
Wow, Some of you would have me in front of a firing squad for using 10w-40? I am just asking guys, there is no need to get hostile. I intend to drain it soon as a matter of fact and use 5/10-30 Mobil1. I gotta admit I am just a bit uncomfy using 5-20 in the summer.
 
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1,835
Location
Ky
I have used and have been using 10W-40 oil without any problems. If one changes their oil regularly and takes descent care of their car,they should not have any problems using this weight. Many years ago,this weight may have caused problems but todays oils are much better and are more refined.This weight of oil should not cause any problems. If the oil isnt causing you any problems,I see no reason not to use it as long as it doesnt void the warrenty.
 
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1,979
Location
Dallas, TX
If it meets the requirements that Honda has set forth for that engine, (SL, etc) it will not void his warranty. Something that I noticed about both of my Civics is that they really seemed to 'perk up' after an oil change, regardless of what I used. Perhaps this is what you're experiencing?
 
Messages
1,627
Location
Timberline
quote:
Originally posted by Schredder: I know my cars seem to run better after they're washed...haha
It does, if radiator washing is a part of that - after mud accumilation of course.
 
Messages
3,094
Location
Metro Detroit
quote:
Originally posted by CBDFrontier06: If it meets the requirements that Honda has set forth for that engine, (SL, etc) it will not void his warranty.
Depending on the wording of the owner's manual, it might actually void the warranty. If Honda is anything like GM, who says "Do not use any other weight", guess what? "Oh I'm sorry, Mr. Accord2005NJ, we're not covering this engine repair as you didn't use a motor oil consistent with the guidelines in your owner's manual." I'm not saying engine repair is a likely scenario, but it's wise to abide by the manufacturer's advise when they can make the decision whether or not to warranty a repair job. Realistically, he could probably get away with anything thinner than gear oil, but if it were my car, I'd be using 5w-20 like the manual said.
 

Accord2005NJ

Thread starter
Messages
189
Location
NJ, USA
Hi, The car just seems to run as if turbocharged a bit. The shifts, however, are a bit harder so i am thinking of switching back to 5-30or 10-30
 
Messages
461
Location
Fredericksburg, VA
That's a good question. You might study a schematic of the oiling system. If you could measure the pressure near the piston, you could probably calculate if it is lifting off without doing a more involved test.
 
Messages
27
Location
California
The higher shift points you have noticed are due to the application of more throttle to overcome the friction of the thicker oil. The computer senses the increased load and raises the shift points, just as it would while climbing a hill.
 
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1,375
Location
Elizabeth. Colorado
It sure doesn't sound any different from all the guys here after they add the elixer of life, Auto RX. He's just going against the grain, not with it. Off with his head!
 
Messages
2,513
Location
Richmond, VA
I use a mix of Havoline 10W-30 and Delo 400 15W-40 truck oil in my 2002 Chevy Cavalier 2200 OHV and my impression is that the thicker mix is better than thinner oil (the engine seems quieter). Gas mileage is the same. I average 31 mpg combined driving. I plan on doing a UOA at the end of the summer and will post back in the UOA section and will make a comment to the "thick oil" threads I see in the other sections. Oh, BTW the mix I use is 2 quarts truck oil and top off (2 1/2 qts Havoline).
 
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