Originally posted by: CptCrunch
I have full synthetic (tho not really synthetic now (mobil1 5w20 full synthetic)) and it runs fine in summer/winter. Just dont switch to synthetic if you have put in non-synthetic motor oil in the past, especially with a camry with that many miles. You will cause problems and have oil leaks/burning oil
Originally posted by: chucky2
The truth is that most 5W-20's are in the upper cSt range of the 20W scale, and that most 5W-30's are in the lower cSt portion of the 30W scale - this is when @100C.
Then, you've got 5W-30's shearing down into upper 20W range anyways, and 20W's being a better "built" oil that don't shear down as much.
Chuck
Originally posted by: cprince
I thought that the lower number is the viscosity when the oil and engine are cold, and the higher number is when the engine reaches operating temperature. http://auto.howstuffworks.com/question164.htm
If this is the case, then the oil would be too thin when your car warms up to operating temperature.
Originally posted by: chucky2
The truth is that most 5W-20's are in the upper cSt range of the 20W scale, and that most 5W-30's are in the lower cSt portion of the 30W scale - this is when @100C.
Then, you've got 5W-30's shearing down into upper 20W range anyways, and 20W's being a better "built" oil that don't shear down as much.
So basically, unless you're tracking your ride and beating the ever living sh1t out of it, you'll be fine.
The reason Ford and Honda went to 20W's instead of 30W's was not only that it saves on gas...it's that 20W's are going to reduce startup wear (where most wear occurs) and that oil technology had finally progressed to the point that dino (read: cheaper oils not having to be synthetic) oil had finally reached the point where 20W would be viable for protection.
Chuck
Originally posted by: wonderwrench
I see your point but why do most if not all oil companies state "SAE 5W-20 should only be used in vehicles where SAE 5W-20 is recommended by manufacturer."
The reason is, the oil companies do not want to be responsible for any possible damage done. If the manufacture specifies 5w20 oil the oil company is not liable as long as their oil meets specs.
The auto manufacturers can claim tighter clearances make up for 5w20 but its a line of bull. They are just doing everything they can to meet CAFE standards.
Yup most engine wear happens on startup. Thats one of the reasons conventional oil is crap. Synthetic is the only way to go. Better hot and cold and they keep engines much cleaner.
On some statements made other posters. I would never use 10w40 in any modern car unless it was called for by the manufacture. Conventional multiviscosity oil's are made by taking a lighter oil and adding viscosity index improver's to make the oil perform as a thicker base oil would at high temperature. So a 5w30 oil is really a SAE 5w oil with viscosity index improver's added to make it perform like a SAE 30 oil at 100C. 10w40 is too far of a stretch. This is because you need to add to much viscosity index improver to get the 40 rating. So get rid of the 10w40. Any car made in the last 30 years should be just fine using 10w30 in hot climates and 5w30 in cold climates. If under extreme heat or load go to a 15w40 or synthetic oil.
Originally posted by: wonderwrench
The only reason Ford and Honda went to 5w20 is for increased fuel economy. Most makers of 5w20 oil have a warning that says " Only use 5w20 if it's recommended by your cars manufacturer " or similar.
Originally posted by: LTC8K6
5W-20 is not any thinner than 5W-30 when it's cold, though.
Originally posted by: exdeath
Originally posted by: wonderwrench
The only reason Ford and Honda went to 5w20 is for increased fuel economy. Most makers of 5w20 oil have a warning that says " Only use 5w20 if it's recommended by your cars manufacturer " or similar.
Also has to do with the increased complexities of valve trains with hydraulic lifters, variable valve train tappets, increase manufacturing precisions and closer tolerances, etc. The thinner oil can reach these areas better, particularly when the engine is cold.
SVT engineers recommend 5W-20 on the Cobras for example because of the tight hand built clearances of engine components.
Originally posted by: wonderwrench
Originally posted by: exdeath
Originally posted by: wonderwrench
The only reason Ford and Honda went to 5w20 is for increased fuel economy. Most makers of 5w20 oil have a warning that says " Only use 5w20 if it's recommended by your cars manufacturer " or similar.
Also has to do with the increased complexities of valve trains with hydraulic lifters, variable valve train tappets, increase manufacturing precisions and closer tolerances, etc. The thinner oil can reach these areas better, particularly when the engine is cold.
SVT engineers recommend 5W-20 on the Cobras for example because of the tight hand built clearances of engine components.
Thats what the manufactures say, its still BS. They use 5w20 to increase fuel economy and 5w20 oil specs called for less burn off than previous oil specs required. So 5w20 helped achieve lower emissions. Read this http://www.epa.gov/otaq/cert/dearmfr/ccd0112.pdf
Sure is strange that the EPA would be so tight on the use of 5w20 if the manufacturers were only using 5w20 because they tightened clearances and for better startup lubrication. 5w20 and 5w30 should have the same viscosity cold so this is a moot point.
Today many oils that are not 5w20 meet the ILSAC GF-3 spec so they have no more burn off than 5w20 oil. So using 5w20 only really increases fuel economy and only marginally at best. 5w20 will increase engine wear at high engine loads and or high temperatures. Oil can only be so thin before metal to metal contact occurs. Also keep in mind over the last several oil spec changes they have all but eliminated the use of Phosphorus and zinc which were the best extreme pressure lubricants available.
Most if not all conventional oils today are not capable of protecting engines under extreme conditions because of the lack of Phosphorus and zinc. 5w20 just will not cut it sorry, the oil film is just to thin at high temps. And do not say people do not drive under extreme conditions as very few do not. Idling in traffic with the ac on when its 90+ degrees . Pulling a trailer when its 90+. Driving at high speed over long distances when its 90+.
The days were engines last near forever if taken care of are over. Synthetic oil's ability to stay in acceptable viscosity range under extreme temps will help but Phosphorus and zinc will affect them also.
Originally posted by: exdeath
Originally posted by: wonderwrench
Originally posted by: exdeath
Originally posted by: wonderwrench
The only reason Ford and Honda went to 5w20 is for increased fuel economy. Most makers of 5w20 oil have a warning that says " Only use 5w20 if it's recommended by your cars manufacturer " or similar.
Also has to do with the increased complexities of valve trains with hydraulic lifters, variable valve train tappets, increase manufacturing precisions and closer tolerances, etc. The thinner oil can reach these areas better, particularly when the engine is cold.
SVT engineers recommend 5W-20 on the Cobras for example because of the tight hand built clearances of engine components.
Thats what the manufactures say, its still BS. They use 5w20 to increase fuel economy and 5w20 oil specs called for less burn off than previous oil specs required. So 5w20 helped achieve lower emissions. Read this http://www.epa.gov/otaq/cert/dearmfr/ccd0112.pdf
Sure is strange that the EPA would be so tight on the use of 5w20 if the manufacturers were only using 5w20 because they tightened clearances and for better startup lubrication. 5w20 and 5w30 should have the same viscosity cold so this is a moot point.
Today many oils that are not 5w20 meet the ILSAC GF-3 spec so they have no more burn off than 5w20 oil. So using 5w20 only really increases fuel economy and only marginally at best. 5w20 will increase engine wear at high engine loads and or high temperatures. Oil can only be so thin before metal to metal contact occurs. Also keep in mind over the last several oil spec changes they have all but eliminated the use of Phosphorus and zinc which were the best extreme pressure lubricants available.
Most if not all conventional oils today are not capable of protecting engines under extreme conditions because of the lack of Phosphorus and zinc. 5w20 just will not cut it sorry, the oil film is just to thin at high temps. And do not say people do not drive under extreme conditions as very few do not. Idling in traffic with the ac on when its 90+ degrees . Pulling a trailer when its 90+. Driving at high speed over long distances when its 90+.
The days were engines last near forever if taken care of are over. Synthetic oil's ability to stay in acceptable viscosity range under extreme temps will help but Phosphorus and zinc will affect them also.
You have an engineering degree?
Also what is the piston to wall clearance of the 2003 Cobra 4v SC engine? Look it up. The engines are built by hand and the engineers who designed and built them say 5W20 and they are a bunch of gear heads who crave power and couldn't care less about 1 MPG. The design was validated on a dyno alternating between max power and max torque for something like 400 hours non stop. That's more extreme than anything you're thinking of.
I hardly think 5W20 was chosen to increase fuel economy by .5 mpg on a car that's only rated 16 MPG in the first place... I just don't think MPG was a priority. Tight clearances may help in efficiency and in meeting CAFE standards (*puke*) thus indirectly linking 5W20 to the cause and effect result of higher fuel economy. But 5W20 is merely a necessitated byproduct to the tighter clearances that are more responsible for the efficiency gains than the oil itself.
It's a bit of a misnomer and logical fallacy:
1) engine built tighter to improve efficiency and mileage
2) thinner oil required for the tighter components
3) therefor thinner oil was chosen for better mileage
I wonder what is worse, going with a lighter oil that flows better at the expense of decreased lubrication or no lubrication at all when you hammer the throttle and oil pressure spikes and the thicker oil doesn't flow as well momentarily in a tight engine.
Originally posted by: wonderwrench
I can use the 2005 Ford GT 5.4L 4V SC engine as my example. NO 5w20 here.
I wonder why they used 5W50?. This is a hand built engine. Holds 9.5 qts of oil. Has a huge oil cooler. Dry sump oil system. ??? Dry sump and 9.5 qts of oil, I don't think you could run the sump dry on this baby.