Coolant leak

6.7 Powerstroker · Nov 22, 2016

My truck's seemed to have developed a coolant leak at the thermostat housing o ring but it seems to leak worse under higher boost/load levels. The coolant level hasn't dropped hardly at all but it's definitely got a leak right at the o-ring where the larger top coolant hose connects to the thermostat housing and cross over and leaves a wet spot in the valley. I know leaks aren't normal but when you have small leak is it normal for the leak to be worse under a higher load or boost? I really doubt I have a head gasket problem since I've had the oil checked and it came back really good compared to other 6.7's with similar mileage (per Blackstone Labs)and had no coolant or fuel dilution. I know Blackstone's not the best place for info but they'd be able to detect coolant in the oil. Would higher boost or load cause the coolant to flow faster causing the pressure to increase or what else could cause the leak to increase when I get on it?

bdm1981 · Nov 27, 2016

Is it the metal tube that slides into the crossover? Mine did that after I did a turbo swap and eventually the o-ring blew out and emptied antifreeze everywhere. Needless to say I will never reuse an o-ring regardless how good it looks. If thats the same one I had leaking I would replaced it as soon as possible...

bdm1981 · Nov 27, 2016

Nevermind. I just noticed you said around the thermostat housing. Still yet I would get it fixed asap.

redneck1 · Nov 27, 2016

My truck does the same thing. Leaks out between the aluminum and the plastic. I dunno if a new thermostat would help or not. My mishmoto low temp didn't leak but since I installed my stock one back in for winter, it leaks. Figured I'll have to drain the coolant and reseal it. Hardly worth a dealership trip as it takes longer to drive to the dealer than do it myself. Just a pita..

KCCO

lincolnlocker · Nov 27, 2016

redneck1 said:
My truck does the same thing. Leaks out between the aluminum and the plastic. I dunno if a new thermostat would help or not. My mishmoto low temp didn't leak but since I installed my stock one back in for winter, it leaks. Figured I'll have to drain the coolant and reseal it. Hardly worth a dealership trip as it takes longer to drive to the dealer than do it myself. Just a pita..

KCCO

where does the coolant leak down to under the truck?.. I am certain my radiator is cracked but that is the only place I see that is wet is on the drivers side end tank and it runs down off the valence support/dog catcher thing.. I just want to make sure that it isn't doing what your guys trucks are doing before i order a mishi rad from Mike tomorrow..

live life full throttle

god bless america and the farmer who feeds your fat ass

redneck1 · Nov 27, 2016

lincolnlocker said:
where does the coolant leak down to under the truck?.. I am certain my radiator is cracked but that is the only place I see that is wet is on the drivers side end tank and it runs down off the valence support/dog catcher thing.. I just want to make sure that it isn't doing what your guys trucks are doing before i order a mishi rad from Mike tomorrow..

live life full throttle

god bless america and the farmer who feeds your fat ass

No, mine's leaking into the valley. It's not a lot, you just notice your valley is wet. But I've never seen any coolant on the ground below my truck.

KCCO

lincolnlocker · Nov 27, 2016

ok so it can't run down and cross to the bottom of the radiator. just makin sure.. lol.. I haven't even looked into the valley of this motor yet.. lol.. hope I don't ever need to either..

live life full throttle

god bless america and the farmer who feeds your fat ass