Coolant Drain Capacity?

[EddieC]

On 2008 Tahoe, 5.3, I know that the owners manual states the coolant capacity is a bit over 4 gallons, but how much actually drains out? I can imagine that the block and perhaps heater retain some. Should I have 3 or 4 gallons on hand to make a change?

 

[OR VietVet]

Have the full 4 gallons on hand and add as needed. Let it warm up completely and add and then drive and recheck and add and be aware that air can get trapped so need to recheck for a couple days after for coolant level.

 

[Doubeleive]

I have never needed more than 2 gallons, if you run a hose thru everything the rest will just be mostly water anyways. when I do it I drain all I can, run a hose thru it, fill it back up with water and citric acid (radiator flush), run it either for a little bit or up to 3 days depending on the flush, drain it, run a hose thru it again, fill it up and drain it again. then put in the fresh coolant

 

[Fless]

The block will retain some fluid, so after the flush and drain, be prepared to add as much full strength coolant that would be required for your desired mix. You can pull one or both of the block drains to get more of the plain water out first but that's not totally necessary if it's just plain water, as @Doubeleive said.

For example, if you want a 50/50 mix in a 4 gal. capacity system, add two gallons of full strength -- not premixed -- coolant. Then top off with clean water; it's best to use distilled.

Just remember that the water retained in the block will dilute the coolant that you add, so don't add pre-diluted coolant if you want a solid mix.

 

[Joseph Garcia]

When I had a radiator hose shred right off its connector while on the road near my house, by the time that I limped home, over 3 gallons of coolant were lost. I recognize that my situation was a bit different, as I was not 'voluntarily' replacing my coolant, and the water pump was literally pumping the coolant out, as I drove back to my home.

 

[Geotrash]

When I had a radiator hose shred right off its connector while on the road near my house, by the time that I limped home, over 3 gallons of coolant were lost. I recognize that my situation was a bit different, as I was not 'voluntarily' replacing my coolant, and the water pump was literally pumping the coolant out, as I drove back to my home.

Did you have the chance to do any forensic analysis and figure out why? With modern polymers in coolant hoses these days, I haven't seen one fail in years. Plastic connectors, yes, but I haven't seen a hose fail in recent memory. I'd be curious what you learned in case there is something I should be paying more attention to. I replace all coolant hoses every 10 years or 100K miles anyway, but I'm still curious.

 

[OR VietVet]

After reading the other responses, I see I should be more clear with my response. My recommendation of 4 gallons there, when refilling, was as a 50/50 mixture. I should stop assuming that is known. It likely was known but I should still not assume.

 

[Doubeleive]

Did you have the chance to do any forensic analysis and figure out why? With modern polymers in coolant hoses these days, I haven't seen one fail in years. Plastic connectors, yes, but I haven't seen a hose fail in recent memory. I'd be curious what you learned in case there is something I should be paying more attention to. I replace all coolant hoses every 10 years or 100K miles anyway, but I'm still curious.

I would have to say one of these hoses actually going bad would be pretty rare
most common you get
1. heater hose T breaks or cracks
2. radiator cracks
3. water pump gasket/seal failure
4. reservoir tank crack
5. heater hose-to-reservoir-to-firewall T cracks

a actual hose breaking otherwise would be pretty rare, I have seen some get a pin-hole leak but that's about it, if one looks "bulbous" like a snake with a big meal in it's tummy that's a good sign it's time to replace it.

a heater core leaking would be pretty rare also but may be more common than a hose actually breaking

either way 10 year replacement is a very good idea.

 

[Joseph Garcia]

Did you have the chance to do any forensic analysis and figure out why? With modern polymers in coolant hoses these days, I haven't seen one fail in years. Plastic connectors, yes, but I haven't seen a hose fail in recent memory. I'd be curious what you learned in case there is something I should be paying more attention to. I replace all coolant hoses every 10 years or 100K miles anyway, but I'm still curious.

The hose completely tore off, about 1 inch back from the quick disconnect coupling (certainly not really an easy 'quick disconnect'), connecting to one of the plastic T connectors near the firewall. Actually, there have been some members here in the Forum who have had coolant hoses shred, and at least one of them right in the exact same location.

Regarding forensics, 1) this happened when I was 'accelerating' against another vehicle from a red light, and I wound out the 6.2 wide open, with presumably the coolant pressure at its greatest, when I hit 6000 RPMs. 2) All of the coolant hoses in the engine bay were the original hoses, with 2007 manufacture dates stenciled on them.

I replaced ALL coolant hoses in the engine bay, as well as the two plastic T connectors.

 

[Geotrash]

The hose completely tore off, about 1 inch back from the quick disconnect coupling (certainly not really an easy 'quick disconnect'), connecting to one of the plastic T connectors near the firewall. Actually, there have been some members here in the Forum who have had coolant hoses shred, and at least one of them right in the exact same location.

Regarding forensics, 1) this happened when I was 'accelerating' against another vehicle from a red light, and I wound out the 6.2 wide open, with presumably the coolant pressure at its greatest, when I hit 6000 RPMs. 2) All of the coolant hoses in the engine bay were the original hoses, with 2007 manufacture dates stenciled on them.

I replaced ALL coolant hoses in the engine bay, as well as the two plastic T connectors.

Thank you, Joseph - that's helpful context. And also the first time I've heard about coolant hoses shredding on these like that. Makes sense the added water pressure from WOT could be enough to overpressure a weak hose though. Wonder if there may have also been some blockage in the radiator core.

Fortunately, I've already done all of the hoses including the T-connectors on both of my Denali's with the Gruven Parts billet tees, as well as replaced the Y near the water pumps with the Dorman metal version.