Lately, my 2.5 has been running very cold during highway trips. The temperature gauge shows a normal 1/3 or so deflection during city driving, but when on the highway with a constant speed, the temp gauge is down to the second hash mark. I travel in Oklahoma/Texas so the cold weather shouldn't prevent it from properly heating up right? Thought maybe spark plugs aren't igniting mixture 100%, but does anyone know what it could be or what it could cause?

 

change your thermostat... which should be changed with coolant.

 

Same here. I don't think it's a problem. It heats right up when I exit the highway and do some city driving.

 

both of you replace your thermostats. Its not normal. the temp gauge is not supposed to fluctuate much after it has reached normal operating temp. Should take no more than 5-10 mins of driving to reach normal operating temp.

 

X2 You are also hurting gas mileage.

 

Is the normal place for the needle to be in the middle? Because my temp gauge has been doing the exact same thing since I bought the car.

 

It should be just below the middle or so.

 

How long should it normally take to get there? Mine takes like 15 minutes...

 

A good OEM thermostat should reach operating temp in < 5 minutes of driving at 40-60 mph. You should notice the temp needle begin to rise quickly in 2-3 mins in moderate outside temps(50-70 F).

good luck

 

2 to 3 minutes of moderate driving and the heater has already kicked in full force.

 

What if the engine runs a bit colder? What does that do?

 

it's not at its max efficiency