2003 Silverado flush or drain and fill coolant?

[ledslinger]

My 2003 Silverado 4.8 has 28K miles. I did a flush and fill with Dex Cool at 6 years and about 20K miles. I've put 8K miles on it in the last 5 years and am going to change the coolant based on time. The cooling system is clean as new, not even a black line in the expansion tank.

Should I do a complete flush or just drain and add new coolant? I'm leaning toward the drain and fill.

 

[JamesBond]

That's what I would do, but I probably wouldn't wait 5 yrs. to do the next one.

 

[LargeCarManX2]

Originally Posted By: JamesBond
That's what I would do, but I probably wouldn't wait 5 yrs. to do the next one.


Five years or 150K is the limit of the new antifreezes....use a test strip to confirm.

28K or even 50K is OVERKILL!

 

[Realtech214]

The FF dexcool was in mine since about a year ago. Came out perfectly clean though

 

[Kira]

Hello, Yo, ledslinger. It sounds like you're doing it the right way. I'm so OCD about these things I'd drain and rinse with distilled water once or twice then add DEX-COOL concentrate as per system capacity.

Your vehicle sounds so clean you probably don't even need to do that. You'd be OK draining all you could and refilling with pre-mix.

Doin' it yourself? Kira

 

[Donald]

These days with long life coolant, I think a drain & flush of the radiator every other year is all that is needed. Stick with name brand coolant (not Dollar Store brand), and I think it best to use the same chemistry that came from the factory. Zerex makes DexCool, Asian, G-05. There is no real good reason not to.

But if I had an older vehicle with "ole green" then I might move up to G-05 (and I did on two vehicles I no longer have.)

 

[Kuato]

Originally Posted By: ledslinger
... I'm leaning toward the drain and fill.


Good choice. IMO a drain and refill of the radiator every 3 years will keep the fluid fresh enough to never have to worry.

 

[ledslinger]

I pull the drain plug and only 4 quarts comes out. So if my info of 15 quart capacity is correct that leaves 11 quarts in the engine and heater. So without pulling the block drains, it isn't possible to install the 7.5 quarts of anti freeze concentrate if I do a flush. What the heck?

 

[ledslinger]

I left it draining, more like dripping for a couple of hours and another gallon came out.

The coolant, like everything else in the cooling system, looks new.

 

[901Memphis]

4 quarts seems pretty low for a v8. Did you open the radiator cap while you had the drain plug open?

Try the lower radiator hose and measure how much you get out.

You would probably be fine with a drain and fill with pre mix.

 

[ledslinger]

A gallon drains out quickly, and another gallon drips out in about two hours. So 8 quarts total drained from a 13 quart (?) system.

It seems that due to the location of the thermostat connecting to the lower radiator hose, it restricts draining. You either pull the thermostat to drain, or wait for the coolant to drip past the thermostat.

Since the system has no residue, I'm confident it needed no flushing. The drain and fill will recharge the additives, I'll do it again in a couple of years. Pulling the plug and refilling takes about 5 minutes, most of the time is waiting for it to drain.

 

[Boss302fan]

Drain and fill every other year or 30K miles...

 

[ledslinger]

Originally Posted By: Boss302fan
Drain and fill every other year or 30K miles...


The mileage interval probably won't ever apply since my 11 year old truck has 28K miles on it.

 

[901Memphis]

Drain and fill every 2-3 years since dex cool is long life.

 

[Boss302fan]

Doing it every other year makes sure the coolant should still be fine to prevent any future corrosion issues...