Cooling System Not Pressurizing

[Tonyrodz]

I noticed after driving for awhile there was no pressure in the upper radiator hose. I occasionally catch a very light odor of antifreeze, outside of the truck. I have a new thermostat and water pump. I had to add antifreeze yesterday to the overflow bottle, because it was low. I didn't overheat tho. I didn't really see any coolant leaking. The hoses and radiator we're reused after my 6.0 swap. Is it safe to drive it like this? I'm about to take it on a 2 hr trip. I've put maybe 400 miles on the swap and I'm assuming it's been this way since I got it back. Never did this before my swap. No coolant on the ground. Any ideas? Ok to drive it like this? Tia.

 

[mizzouguy]

I know you want pressure or the boil temp of the antifreeze mixture lowers pretty significantly.
May want to rent a pressure tester and pump it up with the truck off and see if you can see or hear the leak or if it will hold pressure.

 

[Tonyrodz]

Think it's safe to drive?

 

[mizzouguy]

"Most engines operate at around 90-105C (190-220F), which is very close to the boiling point of this water/coolant mix. Thankfully, there is something else that can be done besides varying the mix- increase the pressure. This is the important part, and the reason why cars aren’t constantly overheating and boiling over. Increasing pressure increases the boiling point of a liquid. For water, it works out to about 2.5 extra degrees F per psi. So if you have 10psi of extra pressure, water will boil at 237f instead of 212. Go up to 15psi, which is normal for a car, and straight water boils at around 121C (250F). This is above the normal operating temperature of most engines so there actually isn’t much reason to worry about the composition of our coolant in a pressurized system."
Found that online and thought it was interesting. I wouldn't go far until i found the leak.

 

[Tonyrodz]

"Most engines operate at around 90-105C (190-220F), which is very close to the boiling point of this water/coolant mix. Thankfully, there is something else that can be done besides varying the mix- increase the pressure. This is the important part, and the reason why cars aren’t constantly overheating and boiling over. Increasing pressure increases the boiling point of a liquid. For water, it works out to about 2.5 extra degrees F per psi. So if you have 10psi of extra pressure, water will boil at 237f instead of 212. Go up to 15psi, which is normal for a car, and straight water boils at around 121C (250F). This is above the normal operating temperature of most engines so there actually isn’t much reason to worry about the composition of our coolant in a pressurized system."
Found that online and thought it was interesting. I wouldn't go far until i found the leak.

Thx for the info. I appreciate it.

 

[2011SSVHOE]

My guess is it's a corroded intake manifold gasket, had that happen to a couple of older GM v8's

 

[Tonyrodz]

My guess is it's a corroded intake manifold gasket, had that happen to a couple of older GM v8's

Intake gaskets are new, just had them replaced in my swap.

 

[95escahoe]

Check the hose that goes from the radiator to the TB & from the TB to the engine one of those could be leaking slightly and unless your looking at either your never gonna notice it with the way it's hidden


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[Tonyrodz]

I def will tomorrow. I took it for another ride. Temp got up but didn't overheat. Still no pressure tho. Gonna chance it and take a little road trip tomorrow.

 

[rockola1971]

Check the notoriously evil heater hose couplings at the heater core. Pay specific attention to the plastic that is part of the heater hose assembly just before the coupling if its all factory.