Hopefully putting this info its own thread will help clear up the confusion caused by the oil viscosity change in 2001.
Nobody should be running 5w20. The switch from 5w30 in 1999 to 5w20 in 2001 on identical engines had nothing to do with wear or reliability issues and everything to do with Ford saving a few bucks by meeting CAFE standards.
Mike Riley, Product Design Engineer with Ford Motor Company:
Quote:
"Moving to 5w20 was driven by ... CAFE requirements. The company believes the switch to lighter viscosity 5w20 oils will reduce carbon dioxide emissions by 190,000 metric tons a year and reduce US fuel consumption by over 21,000,000 gallons a year."
FRPP Group:
Quote:
"DO NOT go back to using 5w-20"
Scott Whitehead - Engine Development Systems Engineer, Ford Motor Company:
Quote:
"I've seen the dyno testing. I've probably looked at several hundred engines disassembled and spread out on inspection tables. And I've been involved in testing to resolve issues where varying the oil viscosity was part of the test. Please do not put 5w-20 or less into a mod motor. Please. This is especially true in 4v motors. 5W-30 is probably a good oil for the street with mixed temperatures."
Often times the bean counters prevail over the engineers, usually to the products detriment. Running the lighter weight oil reduces the engines lifespan, mostly in the connecting rod bearings but everywhere that depends on oil viscosity. BMW's M3 engines are small cubic inch, high reving DOHC engines similar to ours and are spec'd for 15w-60 motor oil. Food for thought.
The fuel mileage difference from running 5w-20 vs 5w-30 is probably less than half a mile per gallon but Ford calculates that over 10's of thousands of cars and realizes a substantial improvement in CAFE figures ($).
Even if you drive like you're on estrogen therapy and never rev your engine over 4000 RPM, your engine will experience accelerated wear because a lot of damage occurs at startup before the oil begins circulating. A balance needs to be struck between oil that is thin enough to circulate efficiently at startup but still retains enough film strength to protect the bearings before oil begins to flow.
There are lighter weight oils that contain anti-wear additives that provide superior protection (Red Line, Amsoil 0w-30 (only)) but these additives often preclude the oil from meeting CAFE standards, not that I care about that for my limited use hot rod. If you believe these manufacturers claims and dont mind taking some risk than those two options may be acceptable.
I think it is best to stick with the wisdom and experience of a Ford engine development engineer who spent hours blowing up DOHC engines using different oil viscosities. Someday I may change my mind and try a specialty oil but for now, 5w-30 Mobil 1, Amsoil and Red Line get my vote.
Todd
Nobody should be running 5w20. The switch from 5w30 in 1999 to 5w20 in 2001 on identical engines had nothing to do with wear or reliability issues and everything to do with Ford saving a few bucks by meeting CAFE standards.
Mike Riley, Product Design Engineer with Ford Motor Company:
Quote:
"Moving to 5w20 was driven by ... CAFE requirements. The company believes the switch to lighter viscosity 5w20 oils will reduce carbon dioxide emissions by 190,000 metric tons a year and reduce US fuel consumption by over 21,000,000 gallons a year."
FRPP Group:
Quote:
"DO NOT go back to using 5w-20"
Scott Whitehead - Engine Development Systems Engineer, Ford Motor Company:
Quote:
"I've seen the dyno testing. I've probably looked at several hundred engines disassembled and spread out on inspection tables. And I've been involved in testing to resolve issues where varying the oil viscosity was part of the test. Please do not put 5w-20 or less into a mod motor. Please. This is especially true in 4v motors. 5W-30 is probably a good oil for the street with mixed temperatures."
Often times the bean counters prevail over the engineers, usually to the products detriment. Running the lighter weight oil reduces the engines lifespan, mostly in the connecting rod bearings but everywhere that depends on oil viscosity. BMW's M3 engines are small cubic inch, high reving DOHC engines similar to ours and are spec'd for 15w-60 motor oil. Food for thought.
The fuel mileage difference from running 5w-20 vs 5w-30 is probably less than half a mile per gallon but Ford calculates that over 10's of thousands of cars and realizes a substantial improvement in CAFE figures ($).
Even if you drive like you're on estrogen therapy and never rev your engine over 4000 RPM, your engine will experience accelerated wear because a lot of damage occurs at startup before the oil begins circulating. A balance needs to be struck between oil that is thin enough to circulate efficiently at startup but still retains enough film strength to protect the bearings before oil begins to flow.
There are lighter weight oils that contain anti-wear additives that provide superior protection (Red Line, Amsoil 0w-30 (only)) but these additives often preclude the oil from meeting CAFE standards, not that I care about that for my limited use hot rod. If you believe these manufacturers claims and dont mind taking some risk than those two options may be acceptable.
I think it is best to stick with the wisdom and experience of a Ford engine development engineer who spent hours blowing up DOHC engines using different oil viscosities. Someday I may change my mind and try a specialty oil but for now, 5w-30 Mobil 1, Amsoil and Red Line get my vote.
Todd
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