I’m in need of some serious help here. I bought this truck in and around May of 2019 from a private seller. When I test drove it, the only issue I noticed is the AC compressor is loud like the bearings are shot it it but it’* still blows extremely cold and doesn’t leak. After about 2 weeks of having the truck, I noticed there was oil spots in my drive way so I decided to give the truck some TLC. So here is a list of things I replaced that weekend.

Valve cover gaskets.
intake manifold gaskets
oil & filter
coil packs
spark plugs & wires
air filter

Two weeks after doing all that work, I was down in Florida working and it was a hot day so I decided to take my lunch and sit in the AC in the truck. It started running hot. So the following weekend, I done more work on this truck. Repairs are below...

New clutch & fan
new water pump
new thermostat
radiator flush
heater core flush

After all that work, it fixed the running hot issue but it did not fix the fact that my low coolant light continues to come on. I’ll check the tank, and it’* almost empty. Does this roughly every week or so. No signs of a coolant leak anywhere. No smoke from exhaust. No milky oil. No wetness anywhere around motor that I can see. No sweet smell in cab. No wetness in cab.

Where is my coolant going? I’m ready to just put this truck up for sale.

Unrelated repairs....

front diff fluid change
transfer case fluid change
rear diff fluid change
new u joints
new transfer case output seal
new rear main seal
rebuilt transmission less than 5000 miles ago
Complete front suspension replacement ( inners & outer tie rods, upper control arm, pitman arm, idler arm, sway bar end links, sway bar bushings, lower ball joints, driver & passenger wheel hubs, front Brake Rotors, front brake pads )
new battery
new starter

This is the first time hearing about either of these.

How much you want for it?
Your coolant is going somewhere. I would guess the intake needs to be done again.

Have you checked the weep hole on the water pump?

Separately: You can drive with the radiator cap (well, overflow tank cap on this) loose so pressure won't build and see if that slows the leak. That could help narrow your search a bit. Could.

Secure the loose cap so it doesn't vibrate off.

Boilerplate: Temporarily. For diagnostic purposes only. Closely monitor coolant temperature for the duration of this test. Individual results may vary. Professional driver on a closed course. Yada yada.

No, I have not checked the weep hole. Honestly, didn’t know there was one. I put some UV dye in it this evening. Going to drive it tomorrow for a while and shine a light and see if I can see anything that way. I’ll post results.

Cool, looking forward to it.

Okay so, I’m an idiot. I put the dye in the truck last night. Drove the truck around for work today and after about 2 hours of driving around I stopped at a car wash and popped the hood to see if I could see the dye.

FOUND THE LEAK.

When I replaced the water pump and thermostat, I replaced the Y pipe hose as well. In doing that I broke the quick connect on the return from the heater core. Replaced it but never thought to replace the input quick connect. Well apparently it has a small-ish leak in it. Saw the dye coming out the bottom side.

Left the car wash and went straight to my local parts store and bought a new quick connect and swapped it out when I got home this evening. I’m sure that stopped my leak since that’* the only place I saw dye. I did go ahead and do a thorough search with the UV light just to be safe. Also had a friend double check.

Hopefully this didn’t waste too much of your time and I do appreciate the in sight. I’m far from a mechanic if it was not apparent.

Thanks!

You are a better wrench than many on here.

Yup, what carfixer007 said ^^^^^^^

Glad you got it sorted out!