Hey guys, before I call the shop I'd like to get some input about an issue that started recently. I have a 2006 v6 and about a week ago noticed the car is not warming up all the way. Now it's winter so of course I start it up about 15 mins before I leave for work in the morning, but even after that and a 10 mile highway drive, the needle on the dash temp gauge is still low, and even fluctuates sometimes. It doesn't go to the mid point but also doesn't go all the way back to cold either, just kind of hovers about 1/4 way between cold and the middle sweet spot I expect it to be. The car is driving fine, shifting fine, etc. Everything I've read has mentioned the thermostat valve stuck open allowing too much coolant to get in. Does this sound right? How dangerous is this to my engine, as in, do I need to call the shop asap for service? Anyone ever had this problem before? I'm concerned my wallet is going to get destroyed D:

 

If the meter is not going back to cold and is staying between cold and normal, then it's not your thermostat stuck open. More than likely a temp sensor gone bad.

 

Do you get heat out of the heater?

 

Is there fluid in the bottle? You may be low on fluid because of a broken thermostat housing Very common on the 4.0

 

Yes there is heat still. It's not as toasty warm as before, but still working.

 

I did check my coolant level yesterday and there is still fluid but it is on the "low" line.

 

Probably the thermostat housing then. Small leak and won't really pressurize the system well. Look on the back side of the housing to see if there is any evidence of fluid. Most of the time it splits back there and spews coolant under the intake manifold. If you don't see it when the car is sitting, start it up and get it as warm as you can and look.

 

A faulty radiator cap will result in low or no pressure as well.

If it's luke warm and no leaks, I'd bet thermostat stuck open.

 

I recently read that on the new cars that you have a rich fuel flow for some minutes after start up, and that it could "wash" the cylinder walls of oil protection. I think that was until about 40 F. The article recommended that warming the car up while was driving was faster and better for the car. I have an '05 GT, don't have the cold weather you have, don't drive it as a "daily driver" but, I do know that after is sits for several days that the lifers clatter only for second or two before the oil makes them quiet. So, as long as your water isn't frozen, you be good to go for a "easy drive" warm up. Especially if you are using a synthetic oil. Then again, I see you are in VA, I'm in NC, so it doesn't get that cold there! As I was typing I was recalling some movie where they talked or many, many degrees below zero. We don't have that here at all.