2003 overheating on trip

[Jeffr]

Hi All,
So, for the first time I took a ride in my 03 to see my grandsons in Temecula, CA from Sun City AZ. Round trip ended up being about 775 miles. I must say I was a little nervous due to not having it very long and the things I've had to replace since owning it for only a few months. All went well except for the return trip, right around Quartsite I was on and incline and the heat gauge went red. Then I reduced my speed and babied it and it came down. Was this a mistake on my part for maybe not switching gears from D5 to D4 of is this normal, can't imagine it is. What do you experts think?

 

[biddle]

Please follow the prompts on future posts. Your subject "D4 to D5" didn't have a model year or summarize your post about overheating. Good topics get more responses.
I updated your subject.

You can use an OBDII Reader to monitor your coolant temperature along with a phone app like Torque.

 

[JohnS]

Without knowing the details, warm temps, high elevations, and steep inclines all make it harder for the cooling system to keep up.

 

[Old Red Bird]

Hi All,
So, for the first time I took a ride in my 03 to see my grandsons in Temecula, CA from Sun City AZ. Round trip ended up being about 775 miles. I must say I was a little nervous due to not having it very long and the things I've had to replace since owning it for only a few months. All went well except for the return trip, right around Quartsite I was on and incline and the heat gauge went red. Then I reduced my speed and babied it and it came down. Was this a mistake on my part for maybe not switching gears from D5 to D4 of is this normal, can't imagine it is. What do you experts think?

Not normal, was the top down, or up using the A/C ? The reason I asked, when the a/c is on the fan works contant, if no a/c is used fan works by coolant temperature' maybe the fan is not working, or maybe the coolant level was low, if it was an extreme angle.