Coolant reservoir empty

i have an 07 tundra with 364k miles on it. So as I always do before a 10 hr road trip I check all fluids. Coolant reservoir was empty so I filled it and looked inside radiator and it was low so I topped it off and headed out. 3 hrs into the trip I hear the radiator blowing steam. As usual some gets on the belt and I watch the temp Guage fluctuate a little Once it dried out all is fine. I stopped to get gas and looked at reservoir and it’s empty. Any ideas? Should I be worried?..

 

any leaks in the engine bay or residues you could see ?
364K miles: original cooling system still ? might be time for new radiator, thermostat and hoses.

 

if he made it on the original radiator to 364K i'm stoked

 

Yes original cap. I’m gonna change it first. No water in oil. No leaks of any kind on garage floor.

 

My water pump has been "seeping" since I bought my Tunny 4 years ago. Most likely a lot longer. I add a cup of coolant maybe every 6 months . Get down underneath and take a real good look at your pump. Seal may have finally failed.

 

I will get Oem parts. Yes original radiator. Only major repairs was the emissions air valve and both air pumps. Lower ball joint. That’s all.

 

The new oem radiator cap fixed the issue. Thanks guys

 

Gonna have to try that, having that exact same issue.

 

Someday in the future I want to say I have even 300k miles on my truck holly crap. That's awesome. I just rolled into 82k the other day. Lol