Oil Viscosity for DOHC

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tmhutch

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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
 
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ShortThrow50

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i run 5w-20 synthetic. Just changed the oil too. Im not about to dump the oil and let that money go to waste based on what that frpp guy said.
 

01MGSVT

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i run 5w20 full synthetic and no problems!! i know alot of people run 0w20 in there cobras and no problems!! so i wouldnt worry about it!! if youve been running 5w20 since 2001 and no problems...why change now :bs:
 

Serpentor

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I use 0-w40 and 5w-40 for turbo diesel truck in the summer here. I burn no oil while still getting awesome mileage. That particular weight of Mobil1 is also supposed to have more of the additives for protecting wear.
 

tmhutch

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lol, that's OK. I know some people will find it useful. As long as the information is all in one place and easily accessable for everyone.
 

VNEMUS

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I think this a great reminder to people, Todd, especially since the average post 99' 4V DOHC owner doesn't have millions of miles of dyno testing, tear down and parts analysis experience under their belt to know otherwise. I've have yet to read a solid argument with documented tech proof from a more reliable source that would not make me follow this advice.:shrug:

I vote to add this information to a sticky and hopefully more people who have yet to be made aware of this debate will see it and make the choice that best suits them.:beer:
 

sideways03

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Thanks for the tip! I was always unsure which to go with, but now it is 5w30 Mobile 1 from here on out :beer:
 

Brutal Metal

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lol, that's OK. I know some people will find it useful. As long as the information is all in one place and easily accessable for everyone.
NO I wasn't making that comment about YOU hutch, It was addressed to the people that consistently say I'm using 5W20 and don't give a F about what anyone else says..:lol:
 

st4ng07

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Actually the main reason they switched to 5w20 in the mod. motors is due to 5w30 taking out followers on some of the mod motors, and also giving a slight improvement to gas mileage.
 

tmhutch

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I think this a great reminder to people, Todd, especially since the average post 99' 4V DOHC owner doesn't have millions of miles of dyno testing, tear down and parts analysis experience under their belt to know otherwise. I've have yet to read a solid argument with documented tech proof from a more reliable source that would not make me follow this advice.:shrug:

I vote to add this information to a sticky and hopefully more people who have yet to be made aware of this debate will see it and make the choice that best suits them.:beer:


Thanks for reiterating that point. I dont think the importance of Scotts statement can be overstated.

I'd like to see it as a sticky too but they are trying to limit them. As a result, these types of posts are now being put in the FAQ section.



Thanks for the tip! I was always unsure which to go with, but now it is 5w30 Mobile 1 from here on out :beer:

:beer:



NO I wasn't making that comment about YOU hutch, It was addressed to the people that consistently say I'm using 5W20 and don't give a F about what anyone else says..:lol:

OK, gotcha. I agree. Let'em run corn oil in the crank case if they want to:eek:



Actually the main reason they switched to 5w20 in the mod. motors is due to 5w30 taking out followers on some of the mod motors, and also giving a slight improvement to gas mileage.

If you have an official source for the follower issue, I'd like to see it. I think it's possible that the poor casting quality and extreme core shift of the 99 heads had more to do with that than the oil. Running a 30w oil shouldnt cause a properly set up valvetrain to fall apart.



I have one question why did the artcle start off being wrote by Scott Whitehead and end with the name Todd as if he wrote it????

The italicized print and quotation marks are meant to separate Scott's words from mine. I'll put a little extra space between the two paragraphs for additional clarity.
 

st4ng07

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I just finished my ford training a few months ago, One of the instructors was talking to me about this. Also was talking to one of the senior master techs he remembers this change happening and something about a tsb. I will def. try to find some more information about this. I guess it only happened to a couple of mod motors. One thing I do not get if ford would have changed it only for cafe req., why did they not change it on the 4.0 SOHC? That still uses a 5w30? I mean climate plays a huge role in which viscosity to run. Definitely an interesting subject.
 

nicolosijm

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Recently switched to 5w-30. I bought my 01 cobra with 32,000 miles about 8 months ago.Didn't notice any oil burning or blow by. I started running Mobile 1 synthetic oil immediatley. 2 months after purchace and running 5-20w I started noticing smoke on start up. If I warm up the vehicle in the garage I would also have a rancid synthic oil smell. Did a compression check and everything was at about 175-180 psi. Drove behind my vehicle and no smoke under hard driving conditions. Installed a catch can on driver side and collected about 5 oz of oil every month. Total loss is about 3/4 quart per 3000 miles. Recently switched to 5-30 and immediatly notice less rancid oil burning smell durining start-up. Will post oil-catch can collection values in future. I'm curious to know if 99 cobra owners experience this problem. It seems 01,03, and 04 Cobra & Mach 1 experience this blow-by (they are the ones that call 5-20w oil). Can 99 owners (using 5-30) chime in on this?
 

st4ng07

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NOTE: Oil use is normally greater during the first 16,100 km (10,000 miles) of service. As mileage increases, oil use generally decreases. Vehicles in normal service should get at least 1,450 km per liter (900 miles per quart) after 16,000 km (10,000 miles) of service. High speed driving, towing, high ambient temperature and other factors may result in greater oil use

Oil consumption is average in vehicles, its bound to happen. That spec. is straight from fords manual.
 

Brutal Metal

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NOTE: Oil use is normally greater during the first 16,100 km (10,000 miles) of service. As mileage increases, oil use generally decreases. Vehicles in normal service should get at least 1,450 km per liter (900 miles per quart) after 16,000 km (10,000 miles) of service. High speed driving, towing, high ambient temperature and other factors may result in greater oil use

Oil consumption is average in vehicles, its bound to happen. That spec. is straight from fords manual.
Yeah but some guys here say they go 4K miles without burning a drop of oil which I find hard to believe? Come on the dipstick is gonna go down a bit?
My new motor burns about a half quart every 4000 miles..
 
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