I let my sister use my Ranger for two weeks last month while her car was in the shop and I've noticed that the radiator has become thirsty. When I first got the truck back both the radiator and the reservoir were bone dry so I filled the radiator up and the reservoir half way. I checked the truck this morning and both are dry again, but there's no leak under the Ranger. What do you think could be the problem?

 

Blown head gasket that's why i refuse to loan my truck to anyone. Do you see any water coming from the tail pipe?

 

I have to go to town tomorrow so I'll check the tail pipe and get back to you. The funny thing is that I never let anyone drive my truck, but I made an exception this time because I felt sorry for my sis. Even the rest of my family were shocked that I did it. She's brutal on vehicles too and since she lives in town she probably started and stopped the truck 20+ times a day.

BTW, do you think trying a can of stop leak in the radiator would hurt anything at this point?

 

How long would you say it was from the time you filled it up to the time it was empty again.

 

I'd say it was a little more than a week. I forgot to mention that the last time I checked the radiator to find that it was dry again was also right after I got the truck back from my sister the second time. Since the last fill up I haven't really driven it that much so I'll keep a closer eye on how fast the coolant disappears this time out (if it still does). I'd also like to point out a couple things.

There's no oil leaking into the radiator and I haven't noticed any sweet or burning smells coming from the exhaust. I also didn’t notice any air bubbles in the radiator fluid when I had my brother rev the engine. As far as water coming from the tail pipe goes, it's just the normal amount of condensation that the truck has always produced. I'll keep you guys updated over the next couple days.

 

i have the exact same issue where every other month or so the reservoir is dry but there is no puddles under the truck, no antifreeze smell in the exhaust, oil looks good, no symptoms at all. i'm curious to see what you find out.

 

I would stay away from the stop leak man! That stuff tends to plug holes that should not be plugged! Keep an eye on the coolant level and see how fast it drops.

 

Thanks for the heads up on the stop leak.

 

Here's a quick update guys. I've put over 100 miles on the Ranger since I last topped off the coolant and right now I'd say that the radiator is about 80% full while the reservoir is completely empty. My brother in law isn't a mechanic, but he does service his own trucks so I asked him to take a look. He said the only leak he could see was a little bit of coolant leaking from the thermostat. I don't know much about working on vehicles myself, but does a leaky thermostat sound about right?

 

Make sure you check out your heater control valve. Mine leaked and I finally found it after a few months. Bought a new one from autozone and it leaked even worse. After a modification its holding up so far. I never saw any puddles either, I guess it only leaked after I started the truck to leave

 

i have the same issue just mines not too bad

 

I would go rent a cooling system pressure tester (free) and make sure you get the right adapter size for your radiator and pump it up to about 15 psi and see if it holds after about 5 minutes. At this time you could look for leaks since the system is pressurized all the way.

 

I would agree with pressure testing the system

 

remove the thermostat, dump some blue devil in there and follow the instructions on the label. worked for my 2.5L over 50,000 miles ago

 

Mine, although not the 4 banger, overflows the overflow tank and empties that out when I am at the dragstrip usually, or accelerating on the freeway, I can drain the extra coolant in the overflow tank in about a day or two usually

 

Mine loses about a quart every two weeks, no visible leaks and no puddles