6.4L Warm-up Time

[Ancient_Guy]

I'm posting the warm-up time for my '08 F350 6.4L in hopes that someone can tell me if it is abnormal or not. It seems awfully long to me and I'm suspecting a stuck thermostat which doesn't fully close. I'm writing here about the engine warm-up time - The tranny warm-up is OK, very fast.

Outside temperature -- 15 deg. Truck heater turned off.
1. Initial warm-up at fast idle ---------------------- 15 seconds.
(abnormally short, sacrificing engine for science)
2. Gauge needle makes first detectable movement ---2.9 miles in 11 min.
(driving very slow to protect engine)
3. Needle just touches the "normal range" mark ----- 4.1 miles in 15 min.
4. Needle passes into the normal range ------------- 4.6 miles in 17 min.
5. Needle fully up and steady ---------------------- 7.5 miles in 22 min.

This 6.4L is a big hunk of iron so I suppose it should take longer to warm up than a typical large aluminum auto engine but these figures mean I could drive to the center of the city of Minneapolis from the suburbs before the engine is fully warm - And it hasn't even gotten cold around here yet!

I did not re-run the test with the cab heater on but I imagine it would lengthen the warmup.
Thanks.

[MrJohnWayne]

Not sure bud. Here where I'm at it takes about 10 minutes (7 miles) for the truck to reach op temp and that is with 40* outside temp.

And yes it is a 6.4, not the truck in my sig.