What happens if you overfill the radiator?

[Al's540i]

I replaced my expansion tank and finally got the broken bleed screw out of my new tank and replaced it with a new one. I filled up the tank and tried performing a bleed. I'm not sure if i did it right but I noticed whenever the engine was on the dip stick would go down in the tank but when the engine was off the stick would be really elevated. I'm pretty sure I overfilled.

Anyways I drove to get some gas and noticed I was leaking coolant. It looked to be coming from the bottom of the expansion tank.

So when I got home I put the car up on ramps and bled the system by leaving the engine running and opening the bleed screw. At first I got steam then bubbly coolant, and then only liquid coolant. I closed it back up and all seems in order..no more leaks....yet.

Should I performed this type of bleed and leave the bleed screw open allowing coolant to come out to get the level of the dipstick back down to normal levels?

[bimmerfiver]

I dunno why you were leaking coolant during your drive? This concerns me as you mention the coolant looked to be coming from the bottom of the expansion tank...I don't understand? Was coolant leaking out...are you certain...and if so...from where?

I overfilled my radiator slightly months ago. Senor Gumbi's Shop did a full coolant swap and I drove home from NJ. I added some coolant the next day as it was a little low. I live on a serious hill, so when I checked the coolant, it seemed lower than it really was...anyway I added maybe 5 ounces, then drove around for a while. Came home, let the car sit and it was now parked on level ground, engine cold, really cold. I opened the rad cap and bam, the stick rose an inch above the level it should've been.

The top of the rad-dipstick is supposed to be level with the opening, once you remove the radiator cap. You need to check this when the car is COLD and on level ground.

Wait till tomorrow am...go outside and first, look for any leaks. Then, open the radiator cap and see how high the stick rises. If it's too high, remove coolant with your wife's Thanksgiving turkey baster*. You'll only need to remove 2, 3 or maybe 4 ounces to get the stick back down. It's not much at all.

Before you go to bed...go out there, make certain all the air is bleed out of the system. Go to bed knowing the air is out and also make certain it doesn't leak. Stand there with a drop light/flashlight for 30 minutes if you have to...you won't sleep thinking about a leak. So make sure it's simply not leaking and all the air is out. Tomorrow am you can tackle the coolant's level in what will take 30 seconds with my, cheesy microfiber towel-coolant level DIY.

*I didn't use a Turkey baster. I was ghetto, I placed a clean microfiber towel down there, soaked up 2-3 ounces, removed towel, squeezed it dry. Bam, the stick was now at perfect level! Here is a turkey and there must be a baster somewhere. I can tell you one thing for damned sure, there is heavy cream in that kitchen:

[filon102]

(lol fucked up smile)

[cal45fan]

too much coolant, no room for expansion=leak of cooling system failure

nice pics

[bimmerfiver]

too much coolant, no room for expansion=leak of cooling system failure

nice pics

That's what ima thinking. He's got too much juice and it poured out from under the cap or the bleeder screw...

[dgz32]

It's my understanding that the cap will allow any overfill to escape under pressure. Now, who knows what might fail in the system before enough pressure builds up allowing for this release.

[BimmerBreaker]

It should bubble out slowly as the engine heats up before any catastrophic failure occurs. As long as the amount of over-fill is small, nothing will happen except some burbling out the top of the cap/

[Al's540i]

That's what ima thinking. He's got too much juice and it poured out from under the cap or the bleeder screw...

Yeah, when I got home I got under the car and checked it reallly good and it appears the coolant came out from either the bleed screw or the lower radiator hose (where it connects to the tank). So I turned the engine back on, and opened the bleed screw and coolant came out after first some bubbles and i closed it back up and let idle. NO spraying anywhere and after turning off engine, there was no leaking.

I think I overfilled and when it got hot enough to expand it found a way out. I'll check it tomorrow when it's cold and it the stick is really high I'll do whatever is necessary to get the stick down level with the opeining of the tank.

thanks.

[Cyrix2k]

Nothing. I think it has a release, so hopefully that's where you're leaking from. I've filled mine up so that the coolant was almost level with the cap and haven't had a problem.