Cooling system flush

[wesd]

Need some advice here - 2011 Silverado Z71 4x4 5.3 - 51k miles. Want to get the coolant flushed to keep it good, what is the procedure? The local GM dealer has a winter special on this I'm thinking to do, is it a good idea to have someone else perform this work? I've done this on my prior trucks before but this one is still like new and want to keep it that way. Thanks.

[sisupower]

Very easy to do. This is how I've don't it in the past. Drain coolant from radiator ,engine block and where ever you can. Fill with water and some dawn soap if coolant is nasty. Start truck and get up to operating temp for 10-15 min. Shut off Drain water. Fill again with just water and run for a bit. Drain again and open cock on bottom of radiator and fill with water and start truck and let it run and cycle water through system. Let it keep draining during this time. Then change thermostat and fill with coolant and you should be good. That's how I've done it in trucks gas/diesel farm equipment and heavy equipment. Never had any issues.

 

 

Sent from my iPhone using Tapatalk

[sisupower]

They also sell coolant flush chemicals that you can use. For really nasty systems dawn dish soap works best

 

 

Sent from my iPhone using Tapatalk

[Bob D]

I can't comment on adding surfactants, but;

I try to keep things simple (lazy?).

I never flush, rather, I buy several gal.s of distilled water ($0.99 ea.).

Drain, fill w/ distilled water, drive around for a day, fill with same. Repeat. Repeat if necessary. Drain & add AF.

[MaverickZ71]

Need some advice here - 2011 Silverado Z71 4x4 5.3 - 51k miles. Want to get the coolant flushed to keep it good, what is the procedure? The local GM dealer has a winter special on this I'm thinking to do, is it a good idea to have someone else perform this work? I've done this on my prior trucks before but this one is still like new and want to keep it that way. Thanks.

 

I always did my own coolant drain/flush/refills in the past, but just paid my GM dealer to drain and refill my 2009 Silverado 5.3L crew cab Z71 4x4.

 

The new Silverado owners manual calls for just a drain and refill, not a drain/flush/refill, so that's what I had them do. My DexCool coolant was in pretty good shape anyway.

 

There is no longer a radiator drain petcock or a radiator cap on these models. That's progress--ha. You have to remove the front plastic underbody shield and a small shield on the passenger side (I had to break a screw mount on this to get it off) to access the lower radiator hose. I bought a GM factory-type lower radiator hose and spring clamps from the dealer in prep for doing it myself, and then saw how the hose is close to the frame rail and it was going to make a big mess in my garage, so I had the dealer do it.

 

Hated paying the dealer for 1.5 hours of labor and an 'environmental fee', but at least they got the orange mess all over their floor, not mine. Doing a drain and refill this way with 50/50% Dexcool premixed coolant will change out about 60% of your coolant. To drain the engine block or heater core is more involved (such as removing engine block plugs and subsequently getting all of the air bubbles out of the system), and costs more.

 

My mechanic told me there was no sludge in the bottom of my radiator or coolant recovery tank, so I'm glad I didn't pay more for the special flush chemical that the service writer was pushing.