2006 Silverado 1500 coolant flush

[Viking0]

Need to flush coolant. Stated from prior post "Just drain the radiator, refill with just (distilled) water. Start car and let warm up and circulate, drain again, repeat until runs clear. Then drain the radiator one last time. Check the capacity of the system, add 1/2 the capacity in pure antifreeze, top the rest off with water (that gives you the 50/50 mix). "

What doesn't make sense to me, capacity 16.8qt, but when drain radiator the last time fluid comes out. Often the total capacity of coolant does not include heater core which is also filled with water. To add 1/2 capacity or about 8 quarts means that amount has drained out the radiator. Is that right? I haven't started this project yet. It would be fantastic if the amount from the radiator drain equals the amount of concentrate needed. After fill, warm up and fill with 50:50 as needed.

 

BTW I do not intend to remove thermostat, or engine drain plug, or use a pressure system. How do you actual get a 50:50 mixture? Will test fluid temp with tester after refill and engine warm up.

[O_J_Simpson]

If it is your original T stat, change it. The new one was redesigned to take car of a design flaw of the plastic breaking loose. use the water hose to flush the core while it is open. You have the rest down. Just burp the system when you are done.

[Viking0]

Thanks. Yes original thermostat, 2006 with 9050 mi! Will replace and need gasket. Lots of people use the garden hose rather than distilled water...no issues? I imagine that works. Burp system means let engine run with cap off and leave over night also with cap off. Is this enough to burp system?

[Supreme Pizza]

A garden hose works good for back-flushing the radiator and heater core, but I would not leave garden hose water in the motor if it can be avoided. I just back-flushed mine the other day, and installed a new thermostat. I used the garden hose, but after that I ran distilled water though the system to flush the garden hose water out. Then I added the antifreeze. You can buy distilled water at any grocery store for $0.80 to $1.00 per gallon. I used 10 gallon of water on mine. You may want to consider buying a TDS meter on eBay or Amazon. They are about $10, and they can be used to check your garden hose water quality. A high TDS is not good for your rig, as it will leave buildup on the internal parts and can cause the water pump seal to fail. If your garden hose water TDS is under 5, it ok to leave in your cooling system. In my area the TDS is in the hundreds.

[Supreme Pizza]

The cooling system is "about" 4 gallons. As for getting a 50/50 mix, here is how I do it:

 

Pull the thermostat housing off and let the water drain out.

Re-install the thermostat housing.

Remove the upper radiator hose.

Pour two gallons of "strait" coolant into the hose and radiator. (do not use the pre-mixed stuff)

Re-attach the radiator hose.

Fill the overflow reservoir to the proper level with a 50/50 mix.

Run the engine until the thermostat opens.

After the thermostat opens, keep raising and lowering the RPM's between 500 and 3k, for about 2 minutes. (cap off)

Install the cap, and drive the rig around the block.

Confirm that the coolant is at the proper level, and that the system is holding pressure.

 

Because the system holds about 4 gallons, pouring the 2 gallons of full strength antifreeze into the system will result in a 50/50 is mix. Topping it off with 50/50 pre-mixed antifreeze will support that correct ratio.

 

After its all done and everything looks good, don't forget to double check the coolant level after driving it for a bit and again after a heat cycle or two.

[Viking0]

Love the idea of garden flush followed up by distilled. Two gallons on conc. coolant seems standard. By displacing the water with an open upper radiator hose with coolant, should the engine be on? Thank you.

[Viking0]

Sorry. It seems you add coolant then close off upper radiator hose and start engine...I think I've got it.

[Viking0]

Which thermostat is preferred:

ACDelco Engine Coolant Thermostat 131-156=12600171 or

ACDelco 131-156 GM Original Equipment Engine Coolant Thermostat /ACDELCO 12T121D

[Supreme Pizza]

For the thermostat, I would recommend getting one that has the OEM "open temperature". You would have to check the temp specs on your rig as well as the temp specs in the listing. From what I have read, using the wrong temperature thermostat can cause the computer to change the timing and/or fuel ratios, although I don't know this for a fact.

[sefiroxx]

Also, use distilled with dexcool. The minerals in tap water will react to with chemicals in dexcool reducing the lifespan of dexcool.

 

Sent from my XT1053 using Tapatalk

[Chubbs878]

A garden hose works good for back-flushing the radiator and heater core, but I would not leave garden hose water in the motor if it can be avoided; after that I ran distilled water though the system to flush the garden hose water out.

This ^

[fkallam]

Here in FL we have hard water, I quit using it and no more heater cores or radiators leaking....I use the premix and drain and fill once a year.