Coolant leak...cant tell where

acf6 · Feb 18, 2013

On saturday i replaced my thermostat because my coolant wasnt getting above 155*, so i did that and im at a steady 188-191 now. I knew i spilt a ton of coolant when i changed it (about 1.5 gallons) and made a mess of the undercarriage but i figured after 200 miles since then it would have dried... (its not coming from tstat or upper rad hose)

Fast forward to today, i got home from work (25 min drive) and an hour later went outside to get firewood, and noticed this puddle under my truck, and my degas bottle almost empty. I parked on the other side of the driveway last night and didnt have any puddles, and didnt see any in my bosses driveway today

I topped off the coolant, started it and let it get back up near temp and crawled under it, and i see coolant dripping off this bolt. The lower rad hose is also completely drenched (and it has a napa sticker on it, pretty hard to f up a hose, but not completely ruling it out) but i dont see any coolant coming out of it. Not sure what this bolt is, and i cant tell if its dripping above that or from what?

this hose has coolant on it too, and my axle, diff, track bar, tie rods etc are covered in coolant already. its kind of near the water pump, but id think itd be a whole lot more coolant than this if that failed?? any ideas, thoughts, occasional leak points would be awesome...thank you!

Dittmerdiesel · Feb 18, 2013

Its possible that the hose to the t-stat is leaking. It may just be running down behind it. Use a small mirror to check the backside of the t stat housing. I just had the same thing happen and that was the problem. It didn't look like it was that until I put a mirror behind.

acf6 · Feb 18, 2013

Thanks for the reply. Do you think its possible it is that hose even a few days later? Ive done about 200 miles since i replaced the thermostat.

pa-powerstroke · Feb 18, 2013

I had the exact same thing happen when I replaced my T-stat. Also couldnt tell where it was coming from and didnt start immediately after I worked on it. I pulled the t stat again and reinstalled it. I dont think it seated correctly the first time I did it. I would suggest just removing the hoses and t stat then re-installing everything. Worked for me

acf6 · Feb 18, 2013

Sounds good! One thing i remember is that i had a hard time getting that clamp (factory clamp) back down the hose onto the thermostat housing side. I believe ive read if you dont get them back exactly where they were, its almost guaranteed to leak. I am going to check that first tomorrow and see...

pa-powerstroke · Feb 18, 2013

Ya they are for sure a pain in the ass. I wouldnt worry that you broke or punctured anything, probly everything didnt quite seat correctly.

Dittmerdiesel · Feb 18, 2013

Those factory clamps are a pain. I actually changed it out for a different hose clamp and no leaks since. You would think it would have leaked right away if that was it but you never know. That would be the first place to look though.

acf6 · Feb 19, 2013

Alright...im not driving it to work today, but i just popped the hood to check out the thermostat housing, there is some coolant on it, and it is wet behind that. the hose also doesnt seem like its down all the way and the clamp is not exactly where it was. going to pick up a worm style clamp on the way home and hope for the best :toast:

acf6 · Feb 19, 2013

Got a pressure tester from one of my friends who is the mechanic for a fleet of about 25 Super Dutys, first thing he said was whyd you buy a 6.0 :-roll

Anyways, got home (not driving my truck) and pumped it upto 15psi...immediately saw coolant flowing from hose on thermostat. Took the hose off, got a worm style hose clamp on the bottom and top and reassembled. Filled it up with coolant, pressure tested again...no leak. Went for a drive upto temp, got back, no leaks, thermostat housing is dry. Going to go check it in an hour or so because thats when i noticed it soaked before

But i believe i am leak-free for $1.50 :-jammin