Engine temp. How quickly does yours rise?

Hey there folks. My 92 4.0L takes forever to reach operating tempurature. It usually will take about 10-15 minutes of driving for it to get up to temp. If it is really cold out (below zero celcius) it rarely ever makes it off the 40 degree peg on the guage. I am thinking that perhaps the t-stat is screwed (failed open) and it isnt allowing the engine to reach prime operating temp. Any other ideas or testimonies of the same problem?

My 99 heats up in about 3 minutes if I take off. 5-7 if it sits and idles.

About the same 5 min or so of country driving out to the main roads, about 10 if I let it idle. Not so much concerned about the coolant reaching operating temp it is more the oil temp that think about. That takes about 20+ minutes to heat up sufficiently to cook off the moisture that is generated during the warm up process. Next time you run it for 5 min check your oil, generally it will still be pretty cold on the dipstick. I guess I kinda tick off drivers behind me in the morning during the winter cause I'm a granny driver for the first 20 minutes staying 5mph under the speed limit on the back roads.

With that kind of problem the thermostat wouldn't be failing to open, it would be stuck open. Might be your problem, my engine heats up in just a few minutes. If the t-stat is stuck open then coolant is flowing freely through the radiator.

Yea, thats what I meant. T-stat failed in the open position. I believe that is a saftey feature on all t-stats manufactured today. I guess its time to change that sucker out and see if that makes a difference.

Thanks for the replies folks

My 92 does the same thing. I have put a new t-stat in it, made no difference. Even with the rad. 1/2 blocked it doesn't get up to 210. JIM.