Went to change the coolant in my wife's 05 Armada last night. I changed the coolant in my pathfinder last weekend with no issues. After draining the coolant, which was very clean (65,000 miles) I didn't think she needed a flush so I closed the yellow plastic drain plug and filled up the radiator til the resevoir tank was full.

Left the cap off both radiator and resevoir tank and started the car. Very quickly I heard a swoosh and looked on the floor of the garage and alot of coolant was on the ground and draining from everywhere it looked. I turned the engine off and looked at the tank and overflow tank and it didn't look like it exploded out of the cap holes. It was clean on top of the engine, but down the back of the radiator and fan and belts coolant was leaking from everywhere it looked.

I washed the garage and engine and refilled the overflow tank and tried starting again. Belts squeeked and coolant started dripping.

I left it til this morning and checked this morning and there is no coolant dripping, all levels are where I left them last night. It seems the coolant only drips when the engine is on. Would this mean the radiator is fine and there could be hose leak?

I'm going to look around in a second, but would like anyone's input as this is annoying.

Thanks for your help.

Ok. I know why no one has responded yet. Because you are thinking what the hell is he talking about.

I went ahead and checked everything and refilled the coolant and started it up again. What had happened is the coolant swooshed out of the radiator cap opening. And continued to drip out. I had to put towels everywhere. Good news - No leak, everything is fine. Let it run for 10 minutes to get the bubbles out and it continued leaking out the top of the radiator, then I refilled and closed the cap and it is working fine now.

Crisis averted. Now on to the transmission fluid change.

By the way is there a transmission filter in the pan that needs to be changed? Or after draining the fluid you just clean the pan?

Thanks,

There's a drain plug on the trans pan, and there is no trans filter to change.

If you are going to flush out your cooling system the radiator open is only to fill your radiator, the plastic reservoir tank is where you fill up your cooling system t level, and how you bleed it. Having the motor running and taking off the radiator cap will, as you found out, cause your coolant to overflow and spill everywhere. The plastic tank has 3 hoses attached to it, one from the radiator, one from the TB and one to the thermostat housing.