I recently replaced my water pump, radiator hoses, and thermostat on my truck about a month ago. Everything seemed fine after the fluid change for 2-3 weeks, no high temps, no leaks, T-stat opened fine. Then a couple of days ago I noticed fluid leaking from my upper radiator hose where it connects to radiator, the hose also backed off the fitting a bit. I figured that I just didn't tighten the clamp enough. Tried pushing the hose on and tightening. Drove a couple miles home checked again still leaking, hose is puffing and ready to blow off, thermostat is not open yet, truck not up to temp. So I let it cool down take off radiator cap, turn on truck and see bubbles in coolant. So I'm thinking maybe head gasket? I then drain some coolant, remove T-stat housing remove T-stat, fill radiator with coolant, so coolant at thermostat housing hole is up to neck, take off drive belt, turn on truck and rev a few times with friend watching, no bubbles in coolant at said location. So what do you guys think, doesn't seem like a head gasket, maybe air in system? Or maybe I just didn't have the upper hose tight enough. How much pressure builds in that upper hose before the T-stat opens? Any help would greatly be appreciated so I can figure this out and start driving the truck again.

 

It is normal for a hose to pressurize when the engine is at full temp, but to swell and appear to be ready to blow off is not normal. The bubbles in the overflow tank could have been from overheating, or the system never bled out properly to begin with. Did you use a Cummins t-stat or did you get a stant or other aftermarket one? In my experience the Cummins t-stats are far superior and worth the extra money.

 

I agree with Tim's asessment of your situation. The quality of aftermarket thermostats is hit and miss. I recommend the Cummins thermostats as well over any other.

 

Hey guys thanks for the replies, I used a Cummins T-Stat, and it seems to have been operating fine the past few weeks.

 

I doubt you have a head gasket issue. You may still have some air trapped in the system, and i bet that new hose isn't the same quality as the original. Some of the after market hoses will swell up huge once heat and pressure is applied.

 

Well I hope you guys are all right, the last thing I need right now is a head gasket issue, although replacing my headbolts with studs suddenly moved to the top of the priority list. Other notable things, when I let some coolant out to remove the T-stat the second time the coolant was clean, as it was when I replaced the water pump. The oil in the engine shows no water globules, although I will know for sure when I change it tomorrow. I agree with you guys, it just seems wierd to see that much pressure in that hose, I thought if anything that thing would almost have a vacuum since the flow of the water pump is pulling out of the radiator with the T-stat closed. My plan is to run it tomorrow in the driveway, if the hose shows signs of popping off, then I might get it towed to have a second set of eyes give it a once over if not I think I will drive it to a shop and get it pressure tested. Thanks for all the input any more thoughts would be appreciated.

 

Just an update, had truck pressure tested, everything came back normal, apparently I probably had a air bubble show up in the upper hose 3 weeks after change.

 

Quite odd, but glad it seems to have been an easy 'fix'.