So my mom recently picked up a 2010 Explorer. Pretty nice, very low miles for the year. Around 70k I think. I was checking it out the other day and noticed on cold start (very cold, it was around 5°) there is a fairly loud tick or click noise. Pretty random interval... and seems to go away as soon as it starts to warm up. The thing has a partial warranty for the first month so just wanting to make sure it’s not serious.