# Best Motor Oil? (Highway Mileage) (Rick? Gary?) **URL:** \ **Category:** Factual Questions\ **Created:** [October 21, 2009, 1:00am UTC](https://boards.straightdope.com/t/best-motor-oil-highway-mileage-rick-gary/514549 "2009-10-21T01:00:07Z")\ **Posts on this page:** 4\ **Page:** 2
**Author:** ![Mr.Slant](https://avatars.discourse-cdn.com/v4/letter/m/c57346/32.png) [@Mr.Slant](https://boards.straightdope.com/u/Mr.Slant)\ **Post date:** [October 22, 2009, 5:45pm UTC](https://boards.straightdope.com/t/best-motor-oil-highway-mileage-rick-gary/514549/21 "2009-10-22T17:45:05Z")
Yeah, the outside temp issue I can see, maybe, but the “uses road salt” part is complete crap. ---
**Author:** ![Saintly\_Loser](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saintly_loser/32/4045_2.png) [@Saintly\_Loser](https://boards.straightdope.com/u/Saintly_Loser)\ **Post date:** [October 22, 2009, 6:25pm UTC](https://boards.straightdope.com/t/best-motor-oil-highway-mileage-rick-gary/514549/22 "2009-10-22T18:25:13Z")
> [@Mr.Slant](#): > > Yeah, the outside temp issue I can see, maybe, but the “uses road salt” part is complete crap. Not saying it isn’t, but couldn’t it be possible that road salt, perhaps mixed with water, gets kicked up by the front tires, into the engine compartment, and some of it gets into the airbox and not all of it is filtered by the air filter, so you end up with corrosive salt in the engine? ---
**Author:** ![Baracus](https://avatars.discourse-cdn.com/v4/letter/b/2bfe46/32.png) [@Baracus](https://boards.straightdope.com/u/Baracus)\ **Post date:** [October 22, 2009, 6:38pm UTC](https://boards.straightdope.com/t/best-motor-oil-highway-mileage-rick-gary/514549/23 "2009-10-22T18:38:06Z")
> [@Saintly\_Loser](#): > > Not saying it isn’t, but couldn’t it be possible that road salt, perhaps mixed with water, gets kicked up by the front tires, into the engine compartment, and some of it gets into the airbox and not all of it is filtered by the air filter, so you end up with corrosive salt in the engine? Doesn’t even have to be that complicated. Even when the roads are dry, salt on the roadway will be aerosolized by the traffic and undoubtedly some will end up in the engine. Not saying that it will be enough to make a difference, but I don’t think you can dismiss it out of hand. ---
**Author:** ![tim\_vipond](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@tim\_vipond](https://boards.straightdope.com/u/tim_vipond)\ **Post date:** [November 3, 2009, 12:54am UTC](https://boards.straightdope.com/t/best-motor-oil-highway-mileage-rick-gary/514549/24 "2009-11-03T00:54:45Z")
> [@Leaffan](#): > > As mentioned in a previous thread (that I can’t find) I now need to put very high mileage on a new car. I settled on a new (well new '09) Hyundai Elantra: great ratings for dependability and for fuel consumption. > > Are there any conclusive studies that prove that any particular oil is in fact better at protecting an engine (high mileage - completely highway) or am I right to think that any approved oil should suffice? Here are the oil viscosities for given temperatures for that particular vehicle: LUBRICANTS & FLUIDS: Engine Oil Grade 1…API\* Signature Series 0W-30 100% Synthetic Motor Oil (SSOQT) SAE 5W-30 Synthetic Motor Oil (ASLQT) XL 5W-30 Synthetic Motor Oil (XLFQT) Above 9F…15W-40 Above 0F…10W-30 Above 19F…20W-50 All TEMPS…5W-20, 5W-30 [1] [1] SAE 5W-20 is preferred. As long as you use an oil that meets these specifications, you should experience long engine life. There are indeed studies showing that certain oils do perform better than other oils in standard ASTM testing by independent labs. Here is one current study comparing top selling oils: [https://www.amsoil.com/lit/g1971.pdf?zo=1181889](https://www.amsoil.com/lit/g1971.pdf?zo=1181889) . [Previous page](https://boards.straightdope.com/t/best-motor-oil-highway-mileage-rick-gary/514549.md?page=1)