# Honda Civic (06) Oil Viscosity **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** civic, honda\ **Created:** [July 12, 2013, 10:46pm UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302 "2013-07-12T22:46:40Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![ibekarl](https://avatars.discourse-cdn.com/v4/letter/i/ea5d25/32.png) [@ibekarl](https://community.cartalk.com/u/ibekarl)\ **Post date:** [July 12, 2013, 10:46pm UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/1 "2013-07-12T22:46:40Z")
I just bought an 06 Civic w/ 101k miles. Honda says to use only 5W20 oil, but I used 5W30? Will there be any negative consequences from this–lower mpg or otherwise? Or is their guidance baloney? ---
**Author:** ![missileman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/missileman/32/1366_2.png) [@missileman](https://community.cartalk.com/u/missileman)\ **Post date:** [July 12, 2013, 10:52pm UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/2 "2013-07-12T22:52:56Z")
Read your owners manual. My vehicle manual gives me the option of using 5W30 over 5W20. I don’t think it’s as much baloney as it’s a way to increase fuel economy which looks good on the factory specs of your Civic. ---
**Author:** ![RemcoW](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/remcow/32/2471_2.png) [@RemcoW](https://community.cartalk.com/u/RemcoW)\ **Post date:** [July 12, 2013, 11:08pm UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/3 "2013-07-12T23:08:06Z")
rtfm ---
**Author:** ![Hokiedad](https://avatars.discourse-cdn.com/v4/letter/h/439d5e/32.png) [@Hokiedad](https://community.cartalk.com/u/Hokiedad)\ **Post date:** [July 13, 2013, 12:07am UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/4 "2013-07-13T00:07:54Z")
The problem is that higher viscosity oil is bad for the engine at startup, which is when the majority of engine wear occurs. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [July 13, 2013, 12:26am UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/5 "2013-07-13T00:26:39Z")
5W30 will be virtually the same viscosity as 5W20 at startup. ---
**Author:** ![UncleTurbo](https://avatars.discourse-cdn.com/v4/letter/u/e9a140/32.png) [@UncleTurbo](https://community.cartalk.com/u/UncleTurbo)\ **Post date:** [July 13, 2013, 12:34am UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/6 "2013-07-13T00:34:52Z")
I wouldn’t do another oil change, but the next oil change make sure you use 5W-20 from then on. It isn’t about start up. Your '06 Civic has the Vtec motor and the heavier weight of the oil in a hot engine is not providing the flow characteristics engineered into the variable valve mechanism. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [July 13, 2013, 12:56am UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/7 "2013-07-13T00:56:31Z")
You’ll get answers from both extremes here but the bottom line is to do what the owner’s manual says-period. Some will claim its just for MPG government calculations but others in the engineering field will say that things like bearing clearances and valves can be affected. I’ll with what the manual says which is 5-20. ---
**Author:** ![jtsanders](https://avatars.discourse-cdn.com/v4/letter/j/c2a13f/32.png) [@jtsanders](https://community.cartalk.com/u/jtsanders)\ **Post date:** [July 13, 2013, 2:02am UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/8 "2013-07-13T02:02:28Z")
I’m with Uncle Turbo. Just go back to the 5W20 the next time you change oil. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [July 13, 2013, 7:09pm UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/9 "2013-07-13T19:09:30Z")
Having used 5W30 instead of 5W40 once will make no difference whatsoever. Both base oil weights have a viscosity index (weight) of 5. The “post W” number represents the ability of the oil to resist flow (its viscosity) when it gets hot. This ability is accomplished by the addition of “viscosity modifiers”, which are microscopic coiled polymers that uncoil when the heat up and halp the oil resist flow at heat. The tradeoff is that the modifiers don;t have the same ability to lubricate, and as more oil is displaced with modifiers the ability of the oil to lubricate becomes reduced. In short, 5W30 maintains its viscosity when hot slightly better but 5W20 lubricates slightly better. The difference is extremely minimal in context with all the other variables that affect the engine’s life. Minimal enough to be below measuring. Your engine’s wear at 400,000 miles will probably be the equivalent of what it would have been at 400,005 miles. Now slap your wrist and go back to bed. You can sleep soundly. ---
**Author:** ![JosephEMeehan](https://avatars.discourse-cdn.com/v4/letter/j/ecc23a/32.png) [@JosephEMeehan](https://community.cartalk.com/u/JosephEMeehan)\ **Post date:** [July 13, 2013, 7:17pm UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/10 "2013-07-13T19:17:10Z")
Nice post the same mountainbike ---
**Author:** ![ibekarl](https://avatars.discourse-cdn.com/v4/letter/i/ea5d25/32.png) [@ibekarl](https://community.cartalk.com/u/ibekarl)\ **Post date:** [July 13, 2013, 8:54pm UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/11 "2013-07-13T20:54:35Z")
Thanks, guys. I’ll switch to 5W20 next oil change regardless–that won’t be too long, because I change oil every 3k–don’t believe in this 7.5k stuff. Nor do I trust the oil usage readout. ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [July 14, 2013, 3:29am UTC](https://community.cartalk.com/t/honda-civic-06-oil-viscosity/80302/12 "2013-07-14T03:29:03Z")
Thank you Joseph.