2002 Ford Escape Steering noises on hot days

When do you hear the noise, over bumps, when turning?

You can't go by what was found on other cars. Ford has more trouble with steering and suspension parts separating, leading to loss of control and crashes than any other manufacturer. The warning clue that an inspection is needed is the squeaking and creaking noises. There are plenty of causes of those noises that are not serious safety issues, but you don't want to assume that. Any car should be inspected at a tire and alignment shop when a noise shows up. The people there are experts at finding those causes of noises, as well as tire wear and other alignment problems.

To go in a different direction, the description of the symptoms and observations in the original post suggest the noise is not related to the steering and suspension systems. The clues are that temperature and humidity affect it. The best suspect is the rubber seal where the steering shaft goes through the firewall. If you can get to it, you can pull it back with a hooked tool so a lubricant can be sprayed onto the shaft. Spray White Lube works well. That's a lithium-based grease that won't wash away when it gets wet.

Probably!

How's that for a definitive answer? Actually, I'm very familiar with that problem in the mid '90s when working at a very nice family-owned Chrysler dealership. There was a rubber cover to pop loose under the dash, then the rubber seal could be pulled back with a cotter pin pick. That's a pick with a screwdriver handle, and the pick has a 90 degree bend on the end. I used Chrysler's "Spray White Lube", but other manufacturers have the same stuff under their own name. That stuff works well because it sprays on very runny. The juice runs into tight places and takes the grease with it, then the liquid evaporates and leaves the grease behind. (Works real well for noisy door hinges). I solved the noise on about a dozen cars, but on those, the noise usually went away in warm weather. Winter was when they acted up the most because the previous grease became hard and ineffective.

Since you observed the noise is related to moisture, I have a suspicion water is hitting the seal from under the car. Due to ease of access, I'd look under the dash first, but you may have better luck getting to the seal from under the car. In my experience, just spraying grease at it will not be a permanent solution. You need to get the grease under the seal, and that means pulling it up in one spot.

CV joints do not make that kind of noise. They will only make a clicking noise when the grooves the marbles run in are worn, and that only occurs when turning to one side, and usually only when backing up. If you do hear a rubbing noise or a high-pitched squeal from the half shaft, suspect the inner CV joint's seal in the transmission housing. Spraying a lubricant on it, if you can get some in there, will make the noise stop, but that is only a short-term cure. The noise will come back within a few hundred miles, but that's enough to verify the diagnosis.

The clue to the steering shaft seal is the vehicle doesn't have to be moving. Axle seals only make noise when the half shaft is rotating, meaning the vehicle is moving.