I have a 2013 f150 stx. Earlier thus year it ran a little hot because of low coolant. I found where the coolant was pooling on the frame front of motor but couldn't find the actual leak for a long time. Last weak I found it leaking i believe from the gasket on the water pump. How common is it for the gasket to go bad but not the pump? I'm hoping I can replace just the gasket.

Not the best angle but it's hard to see

 

Not common at all. If its not leaking from above the pump I would go ahead and replace the pump. You probably arent seeing the weep hole. Make sure its not trailing from farther up.

 

I got home today and checked it. My son drove it to school and back. It was bone dry. Refilled the reservoir and it leaks for a few minutesand stops.
I was thinking maybe a weep hole but it didnt do this before. I might just do the whole water pump

 

Water pumps on the 5.0 is already a common issue, so even if it was just the gasket (it's probably not) pulling off a nearly 13 year old water pump and replacing the gasket while putting the old pump back on is pure foolishness. Especially when The replacement pump can be bought for under 150 dollars. I'd even be more inclined to just do nothing and simply check and top off coolant every day vs. pulling and reinstalling the same pump.

 

Some of these trucks also suffered with a leak at the reservoir bottle hose. Some one here has a link in their signature about leaks: is it @Spiky ?

 

Inspection mirror and flashlight works best for checking the weep hole from top of the engine looking down in my experience.
I am currently chasing a coolant leak as my garage smells like coolant when I come in at night. Checked every hose, fitting, radiator that I can see and no witness marks of coolant yet. Fun waiting for failure to rear its ugly head.

Strongly suggest you change the pump as well if in there or you will just have good practice for doing it again sooner than later most likely. RockAuto has Gates pumps for $50-60 that come with the gasket. Most people put in a rotorcraft thermostat while doing this job as well.

 

Looks to me like there is a leak trail coming from behind the water pump pulley. Time for a new water pump.

 

Yep. Mine currently has a small leak in this location. A few weeks ago when I crawled under the front end to check some other parts I noticed the steering shaft was wet with coolant tracing it back to the quick disconnect fitting on the bottom of the reservoir tank. Ordered a kit to delete the quick disconnect fitting… seems these trucks really don’t like quick disconnect fittings.

For the OP a quick search on the web will show you that the Coyote motors are notorious for water pump reliability. You can find some posts where people had their pumps fail with only around 20k miles (though rare) while others have over 150k miles on them with no issues.
Also as already mentioned with the age of the truck if it hasn’t been done before then it definitely wouldn’t hurt to go ahead and replace the thermostat while you’re there along with new radiator hoses. If you do end up replacing the thermostat make sure that you go with a motorcraft one as aftermarket ones are known to cause issues and also if you go with a cooler thermostat it’s best to have the fans retuned to come on earlier with the cooler temps (a step most people skip).

 

Ive never been one to replace the gaskeg but not the part on something. This time i was just wanting to be cheap. Trying to get my other truck going so i was trying to be cheap. Lol..
I dont know if this is tbe original or not so it probably is smarter to replace the pump too

 

I dont have a good video but now as i fill tbe reservoir I can see water bubble out towards the bottom of the pump. Im hoping it's the pump and nothing elss