Change Antifreeze 2008

[ridewot]

What's the best way to change my antifreeze on my 2008 5.3 Tahoe? From what i see draining by the lower hose is about it
? Looks like i would be only changing half.

 

[Marky Dissod]

What's the best way to change my antifreeze on my 2008 5.3L Tahoe?
From what i see draining by the lower hose is about it?
Looks like i would be only changing half.

Why would you only be draining half?

 

[ridewot]

Why would you only be draining half?

Because there is no way to drain the engine block

 

[Marky Dissod]

Because there is no way to drain the engine block.

Passively draining the engine block is a pain in the arse - think it involves removing the freeze plugs?
However, if you also:
1. actively add 15psi at the reservoir with an external pressure source of some kind (coolant pressure tester)
2. run the engine (at idle) as you disconnect the lower radiator hose
IMPORTANT - do NOT let the engine temp exceed 221F as indicated on the dashboard! Shut the engine down before 221F.
You'll at the very least force MORE out of the engine block, and the radiator as well.

 

[ridewot]

Passively draining the engine block is a pain in the arse - think it involves removing the freeze plugs?
However, if you also:
1. actively add 15psi at the reservoir with an external pressure source of some kind (coolant pressure tester)
2. run the engine (at idle) as you disconnect the lower radiator hose
IMPORTANT - do NOT let the engine temp exceed 221F as indicated on the dashboard! Shut the engine down before 221F.
You'll at the very least force MORE out of the engine block, and the radiator as well.

Great advice thank you!!

 

[me88]

My experience: you take the lower hose off on a cold vehicle, everything gushes out.

When I changed the coolant in mine, I just took off the lower hose at the radiator and let it drain out. The service manual says there is a drain plug on the engine block, but I could not find it. The whole system is supposed to take about 17 quarts, and almost all of it came out if I remember correctly. Then I refilled it with a coolant with GM spec 6277M and bled the system which was not too difficult.

It is a very messy job though, make sure you have a kiddie pool or something similarly shaped to put under there to catch all the liquid.

 

[donjetman]

My notes indicate when I drop the lower hose I only get 2 gals out. So I do this every couple of yrs w/NAPA Orange Dexcool so that the coolant doesn't get too old.

 

[Marky Dissod]

My experience: you take the lower hose off on a cold vehicle, everything gushes out.

... there is no way to drain the engine block

My notes indicate when I drop the lower hose I only get 2 gals out.
So I do this every couple of yrs w/NAPA Orange Dexcool so that the coolant doesn't get too old.

You can't possibly get everything out.
As has been pointed out, the engine block holds onto some coolant when you drain it out passively.

Even with my
'add pressure and use the engine / H2Opump to pump out some more' trick
I've never gotten EVERYTHING out.
The more old coolant you get out, the more anticorrosive agents you are putting back in.
Engine lasts longer.

By the way, if you just added 15psi to the system and let go of the hose, I'm sure more would come out than if you just let the hose go.

 

[j91z28d1]

just draining the radiator is enough to keep the coolent from damaging the engine, which is what you're doing with a flush.

but you can drain the block on a ls if you want, I've done it cause it annoying to keep dealing with the block spilling water everywhere as you move it around. there's a screw in plug on the side. probably both, but I only use one. it's a hassle to get to, very tight and might be tighter in salt road states. but it comes out and drains the block if you really want to.

just Google ls block drain plugs and pics come up from all over. if you have rear heat, they will. front and back core will hold a lot too thou, probably more than the block.