I'd go with OEM as well, but what you've written doesn't tell me there's anything wrong. You are in Bemidji after all (when I lived there in the '50s it was "the icebox of the nation" - before Alaska became a state). Diesels, and Sprinters in particular, don't generate a lot of waste heat, so they naturally don't "...get up to temp easily at 40F or under.". Hopefully you have the booster heater and if you do, you should use that to get your engine up to temp quicker/easier.
FWIW. My 2004 T1N has always been OK for heat. The other day I watched things a bit closer to get some timing. About 30 F ambient. A 1/2 mile back street drive to the expressway entrance ramp. About 2 miles to the toll barrier 55 mph limit. 65 mph limit from there.
Started van @ approx. 7:42 a.m.
Temp hit 145 F about 7:48 a.m.
Temp hit a couple ticks below 180 F about 7:56 a.m.
About 8:07 a.m. still just under 180 F. I reduced the cabin blower fan speed and adjusted the vents because it was starting to get a bit hot.
Not very scientific, but gives an idea of how mine works. Same basic results in colder weather. It just takes a little longer to hit the temperature benchmarks.
I think Gears hit on a good thing to check with the jiggle valve. Anything which allows too much coolant to by-pass the stat will keep operating temperatures down. Any by-pass leakage will not affect summer driving temperatures so much.
I also think the 12 minute change out time and $75.00 parts described by Mr. Schmancy is better time spent and cost effective than a visit to the shop for evaluation. I'd try that first.Hope this does some good. AP/vic
Another data point.
I had problems with my radio/cell phone Bluetooth interface today. Got a call. Laws, common sense, required me to pull off to answer. Pulled into a school parking lot. Old man in a van. Stranger Danger!!!
Anyway. 23F ambient by my dash. Around town driving had my engine temperature up to around 175F interpreted from my OEM gauge needle. Idled during my 16 minute phone conversation. I didn't touch the throttle the entire time. The gauge fell to about 150F and remained there until I drove off. It didn't get anywhere near the low end 110F mark.
FWIW. vic
As always, clicking the blue arrow icon within any quote box will take you to the original post/thread.
If you are describing what happens on the highway, then you should re-read my post above.
