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Motor Oil Preference of V8 Owners

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As of 7/28/03

Brand/Weight Count Percent by Brand
Amsoil 2000 0w-30 4 3.7%  
Amsoil 5w-30 6 5.6% 9.3%
Castrol 5w-30 8 7.5%  
Castrol GTX 5w-20 1 0.9%  
Castrol Syntec 20w50 1 0.9%  
Castrol Syntec 5w30 5 4.7% 14.0%
cheapest "respectable" 5w-30 6 5.6% 5.6%
Havoline 10w30 1 0.9%  
Havoline 15w40 1 0.9% 1.9%
Imperial EXXON Syn 5w30 1 0.9% 0.9%
Mobil 1 0w-30 2 1.9%  
Mobil 1 5w-30 38 35.5%  
Mobil 1 15w-30 1 0.9%  
Mobil 1 10w-40 3 2.8% 42.1%
Mobil 1 0w-40 1 0.9%  
Motorcraft 5w30 5 4.7%  
Motorcraft 5w20 1 0.9%  
Motorcraft 10w30 1 0.9% 6.5%
Oil Extreem 5w3 1 0.9% 0.9%
Pennzoil Synthetic 3 2.8%  
Pennzoil 5w-30 4 3.7% 6.5%
Quaker State 5w-30 3 2.8% 2.8%
Red Line Synthetic 10w-40 1 0.9%  
Red Line Synthetic 5w-30 1 0.9% 1.9%
Valvoline 10w-30 Synthetic 2 1.9%  
Valvoline 5w-30 Synthetic 3 2.8%  
Valvoline 5w-30 3 2.8% 7.5%
Total 107 100.0%  


First let me say I am not a petroleum engineer. I am an engineer who has done some projects selecting oils for use in small gearboxes. I am familiar with some of the industry tests and most of the terms. 

I was concerned when I read that some of the V8 SHO users are selecting oils other than what Ford recommends. If I lived in a very cold climate, I think 0W-30 would be reasonable, especially if the car were parked in an unheated garage or outside. However, I don't see any justification for going to a higher viscosity. To go to 10W, 15W or 20W even in a hot climate risks damaging the oil filter on start-up and unnecessary running with the bypass valve open. Also raising the second number from Ford's recommended 30 to 40 or 50 could place extra load on the oil pump and extra horsepower robbing drag on the engine. What is the offsetting benefit for bearing these risks?

Best regards,
W. Jay Kellogg

I am not a lub engineer either, did not stay at a Holiday Inn last night,  but I agree with everything you say. Our engines were DESIGNED for 5w-30 spec motor oil. I have jumped down to 0w-30 for winter because it can help but I garage my car so I don't need to use 0w30.

If I lived in TX, FL, AL, Barstow CA and new the car would never see sub 100 F for the next 6 months one might risk a 40w but the guy using Mobil 1 0w-40 lives in Alberta CAN.  Kirk swears by Motorcraft 5w-30  and I could try it but I have at least 100 quarts of Mobil 1 5w30 in my garage I will use that up first. .My next 14 oil changes are "paid for" sitting in my garage and at 5k per change that is 70,000 miles.  

As engines age (150K) they can sometimes use thicker than recommended oil on hot days. 

It is the WWF mentality, if 5w-30 is good 20w-50 must be better?  

Have you ever found the oil thread on SHO CLUB? One issue you did not mention is a SHO sucks dry the sump in 7.5 seconds at red line. I don't know if a 40w or 50w oil will get back to the sump in time, at worst a 5w30 will always be better than uncovering the oil pickup in the sump.


Quaker State 5w-30

I can't for the life of me figure how some people think they are capable of making a better lubrication decision that the engineers who designed the machine. These guys using 20w-50 and 15w-40 are living in the past and should be driving a vintage auto. Of course that being said, these same engineers also spec'ed that damn camshaft, so don't expect to win many arguments that way.

Richard Nathan
Indpls., IN


Hey Tim,
My choice is Valvoline DuraBlend 5w30. It has the increased heat protection of synthetic but doesn't seem to sneak by the rings as well as the top dollar stuff. I change oil at 3k mi. and judging by the smell, taste, and appearance it seems to hold up well.

Just for information's sake, I also use only WIX filters.

Greg Newkirk

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