Mixing Delo 400 10w30 and 15w40 for the trip.

Messages
82
Location
Wimberley, Texas
Now that I have got 15w40 and the 10w30 will be picked up tomorrow, how much 15w40 should go in for the trip to Cali? Remember its like 3000 miles round trip and will be a great way to rinse the auto rx.I was thinking maybe half and half in my 5 quart system. They are both delo 400 so I don't think there is any chemistry difference there.But, the Lincoln specifies 5w30 for all temps,probably CAFE influenced.I guess you could call it a slow revving V8, so maybe I shouldn't bother with the 15w40. Maybe all 15w40 would be best for the trip, I don't know.3 people lots of luggage and driving all day 4 days in a row then it gets parked for three weeks(maybe dry start problem there) and then 4 days back.I think the 40c viscosity is like 115 so it would be pretty thick on start up each morning and after those 3 weeks.Maybe I ought to back off to just a quart or two of the 15w40. I figure I should get some in there as I feel the 10w30 will shear quite a bit.If 600 miles on there supreme sheared as bad as it did on this engine I would surely be doing it a favor with some amount of 15w40. What I really can't understand is the blind defendance of 5w30 on the crown vic and town car websites,but maybe with ford recommending 5w20 for this old engine they will defend that too [Roll Eyes] Anyway, thanks for all the help so far!
 
Messages
4,805
Location
Lakeville, MN
quote:
Originally posted by Mr TCar: What I really can't understand is the blind defendance of 5w30 on the crown vic and town car websites,but maybe with ford recommending 5w20 for this old engine they will defend that too [Roll Eyes]
Assuming this is the 4.6 V8, it may have something to do with the fact that 5w30 has proven itself to work very well in that motor. 10w30 has also been fine in a warmer climate. This overwhelming urge to thicken the oil up in these motors that were designed around an xw30 unless you are trying to deal with a consumption issue or a high mileage motor isn't necessary, IMHO, and will result in lower fuel mileage overall. UOA's haven't seemed to suggest a thicker oil is necessary, as any of the x30's or xw20's seems to result in excellent numbers from this series of motors. But what do I know, I'm running 5w20 in a full size truck with the same motor. [Razz]
 
Messages
47,643
Location
Duvall WA - Pacific NW USA
I highly doubt it'll make much difference at road temps. I would choose one of the two and dump it in and drive. I would only worry for cold-cold morning starts. That said I have run Delo 15W-40 at fairly cold temps without any issues...your choice.
 
Messages
4,805
Location
Lakeville, MN
Well, I was running a 5w20 in my '97 F150 with the 4.6 and 162,000 miles on it. No consumption issues. Are you having any consumption issues?
 
Messages
3,321
Location
Bolivia
If you have no consumption problems, I don't see a reason to rais the viscosity. Ford and I here use Chevron 5w30 in everything, with no issues. I haven't seen any shear in analisis. The only vehicle I raised to 15w40 was an Explorer with the 4.0 V-6 that someone put SAE 40 in at 1000 km. It has never been the same.
 
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