Red08

I am planning on changing the coolant in my car (with Dexcool of course). My question is - will it drain better if warmed, or does it really make any difference? As I understand it, the only drain is on the passenger side of the bottom of the radiator. So what I drain, I will replace, knowing I am not going to get it all out. Will I get half of it out?

haljensen

My experience when I installed a thermostat was it's easy to remove at least 2 gallons via the drain. I stopped at 2 gallons since that was enough to clear the thermostat and made it easier to refill (1 gallon of Dexcool and 1 gallon of distilled water). I think you'll be able to get all but a small fraction of the coolant out with the radiator drain.

truckplay

you won't be flushing the engine just that radiator.

drain the radiator, catch the coolant and refill, run the engine and do it again. then pull a hose start the engine slide the garden hose into the radiator hose so you replenish what you flush out. when you are done only clean water should come out. drain the radiator again then fill with coolant and water.

Larry/car

There is a test to check the acidity of coolant. If the acidity is within limits there is really no need to change the fluid.

WHT

You don't want to flush the engine with a hose when using Dex-Cool. Simply drain and refill.

The thin protective surface film on the aluminum block/heads should not be disturbed since (i) it takes some time to reform and (ii) there should not be precipitation or buildup in the engine as with conventional coolants unless your system is leaking.

Changed mine after 5 years and it looked and tested as new.

RocketDawg

I have a 2001 Mazda truck, and it's just my beater vehicle to make runs to Home Depot, etc. I take no pains with it at all except to change the oil.

Last year, the heater basically stopped working. So I took it to NTB to get the thermostat replaced since I didn't want to fool with it, and when they took it off it looked like the whole cooling system was full of mud. They flushed and flushed, replaced the thermostat, filled with new coolant, and it's been fine since then.

Oddly enough, I never had any overheating problems at all. But that was the dirtiest cooling system I've ever seen. I had never changed it.

haljensen

Unless you are trying to maintain an Extended Warranty. GM calls for a coolant change after 5 years. Failure to change could void the warranty.

haljensen

Capacity of my '08 LS3 is 12.5 quarts according to the Service Manual. Drain from the radiator into a container so you can measure how much you removed. Since the radiator drain is the lowest point of the cooling system I'll bet you get at least 95% of the coolant out.

orca1946

Normal drain & refill should do the trick!

SUB VETTE

When I changed mine at the 5 year point I drained the radiator, then refilled with distilled water, ran the engine, then drained again and repeated the process twice more. By the last drain it was pretty clear. I then did the final fill with Dexcool and distlled water 50-50.

NY3quartrs5-oh

Have you owned the car new? I'm asking cause i think the sludge happens when non dexcool fluid is mixed with dexcool.

As far as the OP, from what i've been reading the capacity is 12.6 quarts. When you drain just the radiator its 2 gallons (8 quarts). The other 4.6 qts is ok to leave and just fill with dexcool 50/50 mix diluted water and that's good enough.... I'm doing it soon as well.

beepster

Why is it necessary to use "distilled" water for flushing?

NY3quartrs5-oh

For mineral deposits. I have hard water in my area so it's not good for many things. If the water's not good it will be harmful so distilled is just safer and relatively inexpensive. To flush it may not be needed, but for a high horsepower car that most of us spend a lot of money on, a few dollars for water is worth it.

Red08

Thanks guys for all of the information. I plan to do it within the next week.

haljensen

Who told you that you can only drain 2 gallons thru the radiator?

The radiator is the lowest point on the cooling system so nearly all the coolant will drain thru the radiator.

SUB VETTE

Not necessary, but I have extremely hard water with lots of minerals in my water supply and would rather not leave any deposits in my aluminum cooling system by flushing with it. Use what you want, its your car.

Larry/car

My car is past the warranty period. My coolent is still ok so I'm not going to change it. The worst that could happen; accumulation of debris and if acidic the fluid could over time cause radiator/heator core problems. Lets face it, if a connecting rod fails, the cooling system wouldn't have caused it.

NY3quartrs5-oh

there are only 12.6 quarts in the entire system, if you're only draining the radiator its equal to about 2 gallons or 8 quarts. The other 4.6 quarts are in the block and can't be drained from the radiator plug without "flushing". If i'm wrong i'll gladly concede, but i'm not so sure i'm wrong....

jft69z

The engine block & heater core hold coolant too. The engine has a coolant drain plug on the left & right side of the block.

(NY3Quarters5-oh-...you're not wrong )

From the GM eSI service manual:

•Remove the engine block coolant drain hole plug (2) and seal (1).

•Remove the right side engine block coolant drain hole plug (146) and seal (145).

Bill Dearborn

Don't need to use distilled water. Manual says clean drinkable water. I do several drains and refills until the drained fluid runs clear. Then I add half the systems capacity of straight Dexcool and top off with clean drinkable water. Have been doing this for years on multiple cars with no issues and I live in an area with very hard water. My Tahoe is on its 3rd 5 year batch, the Malibu is on its 2nd 5 year batch and the Vette's coolant was changed when the engine blew.

Bill