If I start my truck and drive about 5 miles to my current job (installing a hardwood floor) it doesnt get to temp... stop and go with a max speed of 50 mph (temp needle climbs about 5/16")

But if I jump on the freeway it warms up in 2 miles...average speed is 70 mph

By warm up, I mean the temp gauge hits maybe 175-180

Does the straight pipe prevent the engine from warming up sooner?

 

No , the straight pipe won't slow your warm up time, the manual tranny CTD seem to take longer to warm up , i have a less than 5 mile drive to school, nothing above 40 mph , and i am nice and toasty warm in the cab by the time i get to school. Might be time for a new thermostat , and if you don't tow , yank the fan off for the winter.

 

If you mean that your heater doesn't warm up until the rpms rise and cool back off when they go down then you should check the coolant level.Or are you just talking about the engine temp?

 

Engine temp...