Coolant leak need opinion

[645i]

My 00 4.4 just blew coolant all over the left side of the engine for the most part, the weird thing no hoses actually blew. I drove the car back home and popped the hood to see where the steam was coming from. It was coming from the top hose connection, the hose is good it was replaced when I did the upper timing chain cover seals and water pump. Since no hoses actually burst could this issue be caused by the radiator being bad. It is the original radiator 167k miles or the T-stat, I am not sure which way the coolant flows through the radiator. Thanks in advance for any help

[SlickGT1]

How about expansiont tank? You know the plastic container on left side, that always blows on most BMWs.

[TwinTurboGTR]

I concur. Or the small return tube on top of the exp tank could develop a crack and blow coolant all over.

[645i]

Originally Posted by SlickGT1

How about expansiont tank? You know the plastic container on left side, that always blows on most BMWs.

Expansion tank is intact, like I said the steam was blowing from the top hose connection( the plastic coupler)

[SlickGT1]

Yea that doesn't mean much though. Could be just the hose. The tank can still rip at the connection. It usually cracks on the corner though. So probably the hose. Not sure if you can just replace the O-ring. I usually just replace them.

[X5Ghost]

Originally Posted by SlickGT1

Yea that doesn't mean much though. Could be just the hose. The tank can still rip at the connection. It usually cracks on the corner though. So probably the hose. Not sure if you can just replace the O-ring. I usually just replace them.

I concur, usually lower corners where it can't be seen until it is removed. The steam can still rise from the source and appear to be coming from the hose.

Also, it is possible the hose is cracked under the clamp. Try to take that end out to look at it?

[HPIA4v2]

if the steam coming from the upper radiator hose (the big hose), how did you replace this? it's a bitch to take off and some people crack the nipple/radiator side when prying the old hose using big flat screw driver. I'd check that or missing old o-ring, or it's not seating correctly. when problem arise due to recent rework, always double check the work. I replaced a noise WP once then had a small leak, turns out the o-ring on the twin ipe was pinched.