2002 malibu coolant flush

[pete_dallas]

Hi. Where is the drain plug on the radiator?

I tried turning what looked like a white drain plug on the front right side (drivers) but it just turned(using a 1/4 socket wrench). Yes, it was turning and not slipping. IT didnt come out after several revolutions. So I just tightened and will try some other way to flush. There was no leak after running engine for hour or so.

Is this the drain plug? Can I use the lower hose to drain?

How many gallons including water will it take to refill after a backwash? How do I get all the water out to put in fresh dexcool and springwater?

Thanks. Pete.

[ShadeTreeBill]

I did the same thing.... the Haynes manual says that is the radiator drain, but mine did the same thing. I gave up on that and pulled the lower radiator hose and the block drain plug (located near the oil filter) to drain old coolant out. Open the expansion tank cap to allow air in, and you can also easily pull the top radiator hose loose on the engine end from the thermostat housing.

I use a large mortar pan (bought at home depot) to catch the coolant, and then insert a water hose in the top radiator hose to flush out old coolant from the radiator. I also stick the hose into the top of the expansion tank, and flush from that direction.

This is a limited flush I am sure, it does not really address the coolant in the heater core.... You can buy the Prestone flush kit, which is a water hose connector that you splice into the return heater line where it comes back from the heater core to the engine block. You get a better flush with this installed.

The only way I know to really get all the water/coolant out is to blow the radiator and block out with compressed air.... I am not sure about this, I have heard it suggested in this forum before....

I was having problems with my coolant light coming on and off, sometimes staying on, etc. I removed the coolant expansion tank and took it out to my shop and flushed in out for a long time with hot water... while banging on it to loosen up all the clotted Dexcool. I was amazed at how much junk I got out of it. Since then, no coolant light problems... apparently this is a known issue with Dexcool, and some say due to oxidation related to leaky expansion tank cap. Replace the expansion tank cap when you flush!

I have been hard pressed to get my cooling system to take more than about 8 quarts of coolant after the flush, though the book says it takes 13.6 qts.... Mine simply won't hold that much.... even after run and cool cycles and adding more coolant....

Make sure the set the heater to high heat when refilling the cooling system, and running the car until the heater starts to blow hot air.... if the heater does not blow hot air, then you have air trapped (no coolant flow) in the heater core.... in the two times I have done this on my 02 Malibu, I have had no problems getting the coolant flowing again!

Sorry for the long winded post! Good Luck... Search this forum, lots of posts here about horrors of Dexcool!

[pete_dallas]

Thanks for the info. I'm planning on doing a backflush.

I have a V6, know which line to I tap/cut into to put the t-fitting?

For flushing, I have to remove the hose near the thermostat only?

After I back flush, do I need to drain the radiator and engine? Or can I just drain radiator and add coolant afterwards and be done (getting a 50/50 ratio with water left in the engine and coolant in the radiator?

If I have to drain the engine, where are the engine plugs located? Do I need any glue/adhesive for the threads afterwards?

[ShadeTreeBill]

Originally Posted by pete_dallas

Thanks for the info. I'm planning on doing a backflush.

I have a V6, know which line to I tap/cut into to put the t-fitting?


The Prestone kit says its the line that returns from the heater core to the thermostat housing. One heater line goes to the thermostat, the other one bypasses around the engine back to the water pump.


For flushing, I have to remove the hose near the thermostat only?

I removed the expansion tank cap, and then removed the lower radiator hose from the radiator, this let most of the coolant out of the radiator. I removed the top radiator hose from the engine, thermostat housing.... and I removed the plug from the block.

After I back flush, do I need to drain the radiator and engine? Or can I just drain radiator and add coolant afterwards and be done (getting a 50/50 ratio with water left in the engine and coolant in the radiator?

I just ran water in with all the openings open, running water until it ran clear. Then I let it drain out naturally. I then filled the system with 50/50 dilute mix.

If I have to drain the engine, where are the engine plugs located?

The coolant plug is screwed into the engine block near the oil filter. Best to raise the car on ramps or jack stands. you can remove the plastic cover from behind the bumper, underneath to make it easier to access the plug. It's pretty tight, I used several ratchet extensions to allow me to put the needed torque to remove the plug. I used blue loctite on the threads when I put it back in. I don't know the torque spec, I just made it pretty tight...


Do I need any glue/adhesive for the threads afterwards?

I used blue loctite.... whatever I happened to have...

good luck!

[johnschmitt]

In the spirit of completeness there is a second block drain plug on the firewall side of the engine, or so i've read.

[ShadeTreeBill]

That's good to know. I bet its a real pain to get to...

[SPRaYeD9]

just let shoot a hole in the radiator, then crash it into a tree

[bcopeland]

The drain plug does just turn and it is on the drivers side. But you can pull it out (with pliers). And don't crash it - you might not get the desired results.