Hi..I just put coolant in the overflow three days ago and it gone again! I'm getting ready to go on a road cruise 2200 miles and need to find out whats going on. the heater works, the water pumps seems to be fine, no whining no sloppyness, belts are good, cant see any obvious issues with the hoses oil is clear transmission fluid is clear Any suggestions would be appreciated

 

It's either leaking onto the ground, or into the engine. You said the oil looked good, have you noticed any white smoke coming from the exhaust?

It's most likely leaking externally. Do a really good check for leaks, watch under the truck when you park it, etc

 

no smoke! I think it maybe the lines between the overflow and the radiator?? its really hard to see, i can see some moisture near the bottom of the radiator on the frame. I've only had the vehicle for 6 months only 140,000 miles on it

 

If your oil looks good, you can still have a leak into the top of the engine. Hopefully, it is not a failure of the lower intake manifold (LIM) gaskets. To check for leaks, it may be necessary to pressurize the system with a hand pump at the radiator cap. This can help find small leaks like pin-holes.

 

thank you

 

Wouldn't the coolant eventually make it's way into the bottom end, and be visible on the dipstick if the LIM gaskets were leaking? Or is it such a small leak, that it doesn't show up?

 

If there is a small leak and the engine is hot, I could imagine that the water could evaporate instead of accumulating in the oil sump. However, if there is a small leak, it will only get worse with the possibility of a catastrophic failure dumping pressurized coolant into the lifter valley.

 

If we're being hypothetical, coolant could be boiling off too, or else being sprayed into the engine compartment and then evaporating without being noticed.

If you're planning a 2200-mile road trip and can't find where it's leaking from, it might be time to admit defeat and take it into a shop where it can be looked at. Even if it's something like the intake manifold gaskets (a pretty good guess on these) or radiator (another good one) it's going to be cheaper and easier to fix it beforehand even if you have to pay someone.

 

Coolant cannot be seen with the naked eye when looking at your oil, dipstick, or whatever.
A lot of times the "chocolate milky" substance people mistake for coolant is actually water. But yes, coolant could also be leaking.
I work in an oil lab,we test both new and used oil. Water and coolant in used oil gets an immediate phone call to the customer.

In this situation, I would take it in. Let them check it out, print out what's wrong, and go to the parts store to buy whats on the list.