[Fosterslaw77]

Ok went on a 1000 mile each way trip. Towing roughly 3k plus enclosed trailer with my bike in it. My deltas were between 7-14 depending on temp. When cool out...under 60 degrees the spread was on larger side. When above 60 degrees they were closer. At one point on I 81 in NC the grade was steep and long and spread went as far as 22 degrees it was about 65-70 degrees out, near top and as soon as I crested hill they dropped immediately to where they were before....within a couple minutes. Usually when empty my truck averages 6-10 degree difference. It's is a 2006 f350 Harley model with 65k. It's is a stock truck with just a 4inch turbo back...muffler only. What do we think about health of the truck. ECT was about 204 and eot was about 226. Top, I run Mobil.1 5/40 right now trying t-6 next time just to see.
Thanks josh

 

[srjd]

the best way to tell is unloaded on flat highway doing about 70mph

 

[Snake]

Correction: 60-65 mph.

Gradually get the truck up to temp (ECT 190 or more). No wide open sprints or stuff like that. Then drive at a constant 60-65 mph for 10-15 min. If you see more than 15* difference in ECT and EOT, the oil cooler is clogged.

As mentioned, no trailer and no load in the bed.

 

[Fosterslaw77]

I have yet to find an area of flat ground for 15 min even 10. I have done it and even going up mild grades it stays at 7-10 tops so I guess it's good for now. So the larger spreads are normal for towing I assume?

 

[Snake]

Yes, you'll see larger deltas when towing. How big they are depends on how hard you're working your truck (weight of trailer, speed, hills, etc). As a FYI, the 6.0 defuels when EOT hits 253* to prevent damage to the engine.

I'm not sure how big the hills are where you tested, but a 7-10* delta is worth keeping your eye on. Sounds like your oil cooler is partially clogged. Probably not replacement time yet, but you're likely to get to that point.

 

[Gridder]

Had delta average of around 22 deg. when testing as others stated on my 05 before replacing oil cooler. Since then have pulled camper (guessing 8500lb. loaded) possibly on same hills as you were pulling and I can't get a 22 deg. delta. Only time delta near 15 is if I top a steep grade and coast. Oil cooler getting plugged, may want to consider coolant flush with restore & restore plus although some suggest this may completely plug oil cooler.

 

[Snake]

I'm one of those who firmly believes that a chemical flush on a partially clogged oil cooler will result in a fully clogged oil cooler. I've seen it happen far too many times.