theedge67

Found this on a website talking about the changes to the 2004 Crown Vic Police Interceptor... keep in mind this is talking about the 2V 4.6L engines, not the newer 3V 4.6L with the VVT http://www.hendonpub.com/secure/arti...ils.asp?ID=226


"5W-20 Oil
Extended discussions were held, both in closed PAB sessions and in open sessions with Ford Fleet, on the use of 5W-20 oil in the 4.6L CVPI engine. In 2001, Ford changed from 5W-30 oil to 5W-20 oil. Lighter oil causes less friction which increased the fuel economy of the 4.6L V-8 and Ford’s overall CAFE rating.

Ford makes it clear, all the way down to putting 5W-20 on the oil filler cap, these newer engines should use 5W-20 oil. Not all agencies do that, including some extremely credible and influential agencies that use oil as heavy as 15W-40. Ford Fleet indicated that its oil viscosity recommendations should be followed, however deviating from those recommendations won’t void the warranty, unless the incorrect oil is determined to be the cause of the failure. In a related topic, Ford Fleet advised 5W-20 oil can be used in any 4.6L CVPI engine of any year all the way back to 1992.

Also on the topic of oil, Ford Fleet indicated that retail cars in normal use should get at least 1,500 miles per quart of oil. Ford Fleet emphasized the oil consumption with the 4.6L engine in police use (severe service) may be greater. If your officers never check the oil, and the oil change interval is the recommended 3,000 miles, it’s very possible that the engine could be several quarts low. If the change interval is much longer than that, the engine may well run completely out of oil. One maintenance issue is clear. Under severe service, someone is probably going to have to add oil between scheduled oil changes.
Ford also emphasized that one hour of idle time is equal to 33 miles on the odometer. Police departments with extensive idle time must factor this in to both the oil consumption rate and the oil change interval. If your patrol cars idle a lot, and you run longer than the recommended 3,000-mile change interval and you don’t check the oil frequently, your patrol car engines are at greatly elevated risk of failure."

metroplex

It's too bad the 2004-up CVPIs are still gutless wonders, even with the 80mm MAF, revised airbox, and straighter zip tubes.

Ford explained the use of 5W-20 in another article and basically it is done to save on gas mileage for the entire Ford fleet. Our powertrain engineers say the same thing (gas mileage purposes). Aussies use 5W-30 in their 5.4L quad-cam V8s in the Falcon XR8.

34124231user

Correct me if I am wrong but, fuel efficiency should = horsepower.

Lower friction and lower pumping losses = more horsepower.

Right?

theedge67

Correct, but if your only talking about .5 mpg difference between 5-20 and 5-30, I would guess that the HP increase is maybe 5-6 at best, probably more like 2-3. Thats just a guess though. The HP increase is probably more noticable at higher RPM's where there is less loss from the oil pump pusing the thinner oil.

metroplex

About 1-3 hp, but insignificant in general. The Ford GT and Shelby GT500 use 5W-50. Using thinner oil to gain horsepower isn't a good idea unless it is a dedicated race car where you can afford the downtime to rebuild the engine.

HOTLAP

I would tend to agree with you and have wondered for some time now what the effects of using 5W -30W would be in the 4.6 3V as I'd like the increased peace of mind. I realize everyone has an "opinion" on oil (especially brands) but can it be said that (all things being equal) 5W - 30W is better protection than 5W - 20W oil?

YardSpecial

I would have to say a FULL syn 5w-30 would be better in the summer months.( aussie is hot as hell)
I ran 5w-30 motorcraft full syn oil and dealer said it was a fine choice. Cobra is not for MPG anyway.

For now while your engine is tight I will stick with 5w-30 and see what my oil lab says (blackstone)