Hello I own a 02 3.8L and today I noticed that when I was on the highway going 65mph my car was running a lil hot. Ive noticed over the years with past cars that my past engines have cooled off on the highway rather then heat up with the wind blowing against it.. Now why would my engine be hotter on the highway and cooler (below normal) on the streets?

 

I had the same thing happen and it was because I was missing the air dam. Take a look underneath and see if it is intact. Check the simple things first...lol

 

could have debris in font of or between the radiator and the a/c condenser, could be missing the air dam, low coolant level, sticky thermostat

 

If the thermostat was faulty wouldn't it throw a code?

 

no codes only come from electronic sensors

 

Some cars do have a sensor after or on the thermostat for just that reason but this car does not.

 

Definitely check between the radiator and condenser. I found years worth of leaves and junk shoved in there in mine.

 

The 3800 engine likes to run around 210° which should be the middle of your gauge, this is normal. If you have been running lower than that then you have been too low and actually losing economy and performance.

If your temps where higher than the 210 mark then check what other's have suggested. Also make sure you are not leaking coolant from the heater hose manifold where it goes into the intake and waterpump.

Massey

 

really? My gauge is always between 160 - 200. If I'm idling for at least 5-10min it'll keep rising until I start driving again and it'll drop back down.

Its suppose to be at least 210? How come mine doesn't? Fluid is topped off at radiator cap. Do I add some also to the overflow jug?

 

I think that's what it is for but that won't cause your issue if the rad is topped off. What does the temp gadge say when your idling versus cruising?