Change raditor fluid

[Romeo3]

Hello, i want to change the radiator fluid in my 98 chev malibu v6. I dont see a rad cap to re-fill with new fluid. How is the fluid refilled in the car. I hear you pour the new antifreeze in the reserve bottle with the engine running and the car sucks in the new antifreeze as it need it.

Also how is the drain plug opened on this car. from reading this forum one says you unscrew clockwise, another says you pull it out to drain and push in to close.

[bottomtech]

If I remember correctly, the radiator drain unscrews about 1/8 turn counter clockwise, then pulls out.
The coolant reservoir has a pressure cap screwed on top. It is part of the cooling system and is pressurized as well. All you have to do is add fluid to the reservoir and it will run down into the engine and radiator. Fill the coolant with the vehicle shut off until it is just over the cold line on the tank, then open the little black 7mm bolt sticking up above the water pump on top of the black tube that runs across the front of the motor to the throttle body. Hold the screw open until coolant comes out, then close it. Now you can run the engine til it warms up, keeping the level up. Don't let it overflow, if it starts to, put the cap back on and let it run until the cooling fans come on. Shut it off, let it cool and re-check the level.

[wpbharry]

Be aware that changing the antifreeze (which is recommended every 5 years), assuming you have the V-6, will likely cause the intake manifold gaskets to go quickly thereafter, assuming that they haven't already been replaced (they go on ALL of the 3100 and 3400's eventually). Not a cheap thing to fix, unless you have an extended warranty still in force, and not something that most folks can handle themselves. Exactly the sequence of events that happened to me last summer. My EW was still in force then, thank God.

[bottomtech]

I do agree with wpbharry somewhat. Most all intakes in our area leak before 50k, long before the fluid is flushed. In fact, if the vehicle is almost out of warranty we look real close for beginning signs, which you can usually find.
What causes the leaks is that the engine block is iron but the heads and intake are aluminum. The alum. expands and contracts much more than the iron, which puts alot of stress on the plastic\rubber gasket. When it gets real cold outside (10 F or less) the aluminum contracts so much that the end bolts loosen up. This makes the gaskets lose their seal. Most all of the good leakers will have the outside bolts only finger tight.
GM's fix for these leaks was originally putting blue threadlocker on the bolts when changing gaskets, now they've updated to new bolts with better threadlocker and higher torques.
Beware, when you see coolant leaking on the outside, there is a good chance just as much is leaking into the lifter valley and contaminating the oil. If yours has been leaking awhile, take off the oil cap and look for a brownish sludge. The whole inside of the engine is like this and your bearings are almost gone. I do alot of long blocks because of this.