Motorcraft 5w20 on a long trip in the summer heat?

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Oct 13, 2003
Greencastle, IN
I have an '03 F150 with the 4.2 v6. I am driving from Indiana to California and back this summer and expect to put on 5500-6000 miles. This will be highway driving which should be easy on the oil but I expect temps will reach 100F or so. With the UOA's I've seen on this oil, which many show plenty of TBN after 3,000 or 4,000 miles, I am wondering if I could make this trip without an oil change midway through?
I'd be very confident that this oil would go that long under those conditions. Highway driving is very easy on the oil, even in 100F temps, as long as you're at steady throttle the oil temps shouldn't be high at all. In stop and go traffic in 100F temps the oil would get a lot hotter, but not on the highway, it should be closer to the engine's coolant temperature under those conditions.
"Summer = Hard on oil." Not necessarily. Good point, Patman, one that's missed by many folks. If a cooling system keeps the engine at a constant XXX degrees F, then the oil neither knows, nor cares, if the outside ambient temperature is 50 degrees or 110 degrees. For cooling systems which are more than capable of sufficient cooling, even when towing in August, the only real oil challenge is winter cold-starts. [ March 10, 2004, 08:32 PM: Message edited by: TC ]
These Motorcraft oils are very good and you will have no problems with them. MC, Pennzoil and Chevron might be the best bargain in oils right now, even among synthetics.
I made a trip in my f150 4.2 automatic last summer. Texas to Michigan, and back. You're in for a surprise! I used the cruise control set at 72 - 73 mph. On some hills the truck down shifted out of OD, to 3rd, to 2nd gear! I thought it would blow up before I got the cruise disengaged. That trip was much harder on the motor than my daily driving is. This motor just can't handle the wind resistance at highway speeds. I recommend 10w30 blend and a heavy duty WIX 51516 for your trip.
Every single older owners manual that permits teh sue of 5w-20 says : Eitehr " DO not run at ambient temps above 70F" or "Do not use in profonged hiway driving" Yes, oils have gotten better but consider, that in those days engines tended to run cooler! Your application calls for a 50 weight oil, regardless of what the wonersd amnual says. Its still an internal combustion engine and buld clearances really havent changed all that much since the 80's. Fred... [Smile]
As if we haven't made made any headway in producing higher quality oils in the years since those recommendations were made... Honestly, a 5w20 oil formulated to meet the Ford spec is in all likelyhood a better quality oil than those found in other grades under the same brand. I'm growing more tired with the old school thick oil is better perception every day. I've been using 5w30 oil constantly since 1988, while many folks here would have you convinced I should have had multiple engine failures by now. As suggested, bring a qt or two with in case you do need to top off. You'll be fine without foing an oil change until you are bak.
If mine I'd be tempted to run Delvac 1 or similar. 100 degree temps may not stress the oil under a steady moderate cruise but throw in some western mountain passes or stop and go driving.Your engine will be seeing few of the warmup cycles which favor the lighter grades. IMO the 5W-40 is closer to the target here.
BTW Some western areas in summer far exceed 100 degrees during the day. The lower Colorado river valley sees 108 on cool summer days. 120 can be counted on at least occasionally with 115 very common. This weather is on the upper edge of what the engines are designed for. You'll really get the feeling of heat when you pop the hood after running across the desert in 120 degree weather.
I took a trip from Indiana to Florida last September and wanted optimal gas milage so I used M1 0w-20. Granted, my trip was a lot shorter than yours will be and the air temp was less, but if you are concerned you may consider using M1 as it is a true synthetic and take some top off oil with you. Also, I have seen a line of thinking on this board that the thinner oils are better at cooling the engine.
Service it right before you leave and pack some top up oil and you should be fine. When you add oil, you are always giving the TBN a boost. Sustained hi-speed Interstate driving will always require some top up oil. Use the Motorcraft oil or a full synthetic in the grade Ford recommends and you will be fine.
Just to add to my comments above, I lived in Colorado for five years with frequent trips to Utah, Arizona, and Nevada. I ran all using 5w30 in a little 4 cylinder with a three speed auto. I'll let you figure out what kind of rev's that motor saw on mountain passes and freeway cruising. All I can say is life is much better now with a V8. [Smile] Never missed a beat in the heating or cooling systems under those conditions. Perhaps it has more to do with proper regular maintenance...
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