Car overheats when driving, not when idling.

Seen this happen a lot. Make sure the fans are running in the correct direction.

I'm going to be a little ignorant here; how do I tell and in what direction should they be going?

If they are mounted in the engine compartment they should be pulling air through the radiator. If they are mounted just behind the grill they should be pushing air through. Both types of fans will be exhausting air into the engine compartment. Make sense?

Sounds like a bad water pump. An engine that overheats only when driving has a coolant circulation problem. You replaced the thermostat so the next suspect is the water pump. Other causes may be a cooling system blocked by rust and junk, air trapped in the cooling system, a lower radiator hose collapsing under higher engine RPMs, and a very low coolant level. This is not an airflow problem. An engine that overheats only at idle has an airflow problem. BTW I've seen water pumps that don't leak or make noise but the impeller inside has rusted away causing poor circulation. Hope that helps! Jim

I am currently having the same problem with my 2016 Hyundai Elentra, overheats when driving but if I slow down or stop for a second the temperature goes back down. The car is fine while idling. I was just wandering if you ever fixed the problem if so what was the solution? TIA