1995 Ford F-150 with a 5.0L. I have a leak somewhere. I can fill my overflow tank up to where it says cold fill and drove it for 10 min and check it and it's gone. I don't know where it's leaking or if it is. Someone help me. I'm going to unhook the hose to my heater core and bypass my heater core tomorrow to see if that's where it's leaking. Any advice or suggestions help. Thanks in advance!

 

1st: Make sure your radiator is actually full, not just the overflow tank. 2nd: More than likely emptying that fast means the leak is in the overflow tank/line from tank to top of rad. If the leak were in the system your overflow tank would remain full until the system started to depressurize and sucked all of the fluid back in.

 

I know the rad is full because I filled it today and the overflow to the fill line. And that's what I was thinking the leak was going to be at but I called my dad and he said it could be that or the heater core. Because sometimes in he truck you can smell antifreeze which happens a lot when your heater core leaks.

 

Does the line from the overflow go from the bottom of the overflow to where on the rad? I will check it tomorrow before I bypass the heater core.

 

The heater core would drain the radiator, and you would have a huge puddle just behind the front passenger tire, may also end up with coolant in the cab depending on where the hole is.

 

Alright thanks man! I'll see if I can find it tomorrow.

 

You should see it as soon as you look towards the overflow/radiator cap. It comes from the bottom of the tank to a nipple just below the rad cap. You should pull the overflow tank assembly (remember to disconnect the washer fluid connector) and check it for cracks.

 

Usually when the heater core is going bad you have a bitch of a time defogging your windshield (like on a rainy night). That's a pretty sure sign.
There's an access door right behind the glove box that makes it fairly simple to swap out the heater core - take you easily less than an hour to do. And they're not real expensive.
Go to a wrecking yard and practice pulling one out. If it's in good shape, shove it in your truck. Just don't pull the hoses off (under the hood). Cut them off.

 

Pulling one in a junk yard for practice is a good idea. However, even if the unit looks perfect I wouldn't use it. Once all the fluids are drained from when the junkyard takes the truck in air gets in there and can start oxidizing the aluminum. I've known 6 people personally that used cores out of the junkyard that looked to be in great condition. 4 of those cores either developed small leaks or burst on a seam within 2 or 3 months.

 

Alright thanks guys. I think I'm going to take it down to a rad shop and have it flushed and rodded. Hopefully it is just plugged up. If it's not that I'm going to check the water pump then I guess just remove the new thermostat I might have got a faulty one.