Disappearing Coolant

[Red STX]

Hey guys, I don't post much here, but I'd greatly appreciate a little advice. I hope I posted this question in the correct subforum.

I have a 1997 Ranger CrewCab 4x4 with the 4.0L V6 and an automatic trans. My problem is that I every time I open my hood, my coolant overflow bottle is bone dry. I can't find any leaks in the hoses, and there's no puddle of coolant under the truck after I park. I just changed the oil not long ago, and it didn't look like a milkshake, and I don't have any white smoke out of the exhaust so as far as I know there's no head gasket problems. Operating temperature is always totally normal. I am dumbfounded as to where all this coolant could be going. It seems to disappear into thin air. Any advice would be greatly appreciated.

 

[RonD]

Check the Overflow hose.

On my 4.0l it runs across the top of the rad, and of course it is only used when rad is hot.
Mine had a crack in the hose so when in use coolant leaked and would evaporate quickly so over a few days overflow tank ran dry.

 

[Red STX]

Thank you, I will check that. Also an update I popped off my radiator cap and it was low as well. It took about 3/4 of a gallon to bring it back up.

 

[JimRummy]

Interesting, I have a similar problem.. does it matter what type of hose is used? I have some extra high temp vacuum line, was just wondering if that'd work.

 

[RonD]

Coolant in overflow hose would be 200degF to 230degF and at 0 to 1psi, so pretty much any hose should be fine

 

[Red STX]

Sorry about not replying....life kinda slapped me across the face. I checked the overflow hose and did not find any cracks. I checked the coolant again. The overflow was empty again and the radiator was about an inch low.

 

[RonD]

Sorry for your trouble

You may need to rent/get a cooling system pressure test kit.
It is a rad cap with a pump fitting and pressure gauge.
Usually a hand pump.
You apply 18psi of pressure to cold engine cooling system and start looking/feeling around to find the leak.

It is there but most likely in a spot where coolant is evaporating on hot parts before dripping on the ground.

 

[brentmc]

It could be a bad radiator cap. If its not holding enough pressure and allowing the water to evaporate. I don't remember off the top of my head but I believe for every 3lbs of pressure it raises the boiling point 1 degree. So if your water is boiling in the radiator it gets released as stream. Then as the system cools what little water/steam was caught it the puke tank would be sucked back in.

 

[cthudak]

I would check the air mix box drain tube on the firewall. My 97 Ranger had a small heater core leak. small enough not to get fogged up windshield during defrost, but enough to drain overflow tank after a few weeks.

 

[adsm08]

I believe for every 3lbs of pressure it raises the boiling point 1 degree.

More or less, but those numbers can vary widely based on your actual coolant mix and height above sea-level.

 

[Karbuster]

2003 4.0l ranger here
same problem, fill overflow, becomes bone dry after a few days, replaced thermostat because it was stuck open and didnt notice anything out of the ordinary, checked rad cap, proper 16lbs cap, at my wits end

 

[brentmc]

Maybe the over flow hose has a small leak. I know when I was losing coolant I had a cracked head. I also had exhaust gasses in my coolant as well.

 

[Red STX]

I know it's been a long time guys, but I figured I'd let everyone know how this ended since you all were kind enough to try to help me. I had a mechanic at work look at the truck real quick today, and he found a leak near the driver's side exhaust manifold that I had somehow repeatedly missed. It's looking like a blown head gasket. At least it's leaking to the outside, instead of to the combustion chamber. That would explain why coolant wasn't showing up in the oil. It also explains why I never saw any drippage. The coolant would run down to the manifold and evaporate, making a pleasant maple syrup smell in the process. That should have been the dead give away right there. In any case, the truck runs fine and doesn't overheat, so I'm going to just continue adding coolant periodically until I can get around to getting it fixed.

 

[enjr44]

If it were mine and since it is external leak, I would try a "FIBER" stop leak. Can't hurt anything and may stop it. Don't use anything but the GM type fiber stop leak.

 

[Red STX]

If it were mine and since it is external leak, I would try a "FIBER" stop leak. Can't hurt anything and may stop it. Don't use anything but the GM type fiber stop leak.

I've seen various "stop leak" products at Autozone and always questioned whether they actually worked / didn't make things worse when it came time to do the repair properly. What is a "fiber" stop leak?