Overheating

[ger]

Engine overheats only when external temperature reaches above 84 degrees. Suggestions? I'm thinking thermostat sticking.
Thanks

 

[EdP]

Engine overheats only when external temperature reaches above 84 degrees. Suggestions? I'm thinking thermostat sticking.
Thanks

If the thermostat did not open at all it would overheat when it is 30 degrees outside since there is no circulation. If it is partly open, possible. You can check it in a pot of water on the stove. Not sure how easy it is to get out.

How are the hoses? If one collapses it would restrict flow.
Are radiator fins clear? Any noise from the water pump? Coolant should be good for 10 years.

 

[DaleNet]

Also, did you have the coolant changed recently? These are closed systems and if the air did not get bled, you will get an air lock that will stop flow when hot.

 

[glennk]

Start the car, open the hood and turn the A/C on. Both fans under the hood should be spinning.

 

[optimagenesis]

Engine overheats only when external temperature reaches above 84 degrees. Suggestions? I'm thinking thermostat sticking.
Thanks

When was the coolant service done on your vehicle.
Coolant overtime will lose heat exchange and rust inhibitor chemicals agents. have your fan checked if it is working properly. Check the coolant reservoir level.
Update please

 

[joegr]

Start the car, open the hood and turn the A/C on. Both fans under the hood should be spinning.

Both fans?
DH only has one engine cooling fan. I want to see a picture of your apparently custom setup.