Coolant seep on 02 E53 4.4i! Where is it coming from?

[Mr_E53]

Hi Team,
I have a 2002 E53 X5 4.4i.
Occasionally it comes up with CHECK COOLANT LEVEL on the cluster, so I top it and started to investigated as to where is coming from;

* I've had a thorough look at the rear of the valley cover from the top of the motor, I could not spot any leaks there.

* I've tried to inspect it from the bottom of the motor around the bell housing area, no go there either.

So far only evidence I have is; the bottom of the bell housing has 3 holes closest to the motor end what appear to be water runaway or breather holes. They are just in front of the rubber inspection hole on the bell housing.
Looking at the 3 holes I can clearly see evidence of a coolant seep.

Any ideas or help appreciated!

[djc]

I found that the coolant expansion tank was cracked and leaking slowly on my 03 4.4i. All better now. If you are still having difficulty, try Steve or Phil at Purely Prestige in Narre Warren. They're good guys, both BMW trained.

David

[Mr_E53]

Definitely not the expansion tank. Its something that at the rear of the motor which is slowly seeping between the motor and bell housing.

[jst2878]

pressure test it

[alpac]

Could be different things. I few years ago I had a small coolant leak that was very difficult to locate for several days until it became a big problem. It turned out that one of the plastic connectors that connect coolant hoses was cracked. http://www.xoutpost.com/bmw-sav-foru...oken-hose.html

Another possibility is the valley pan. See this post http://www.xoutpost.com/bmw-sav-foru...alley-pan.html

[RMBags]

Intesting timing of this post since I was experiencing the very same issues with our 2002 X5 4.4i. Coolant Level warnings happened twice in the past month. I had this problem before and replaced the valley pan in 12/2007 at 73k miles and then the same issues again in 1/08 when the water pump failed 80k miles.

Wife was driving the car yesterday afternoon and had massive coolant loss. Fortunately she was able to pull over quickly and I'm hoping no engine overheating damage. Car is at my indie mechanic now and I'm waiting for the diagnosis. Car now has 90k miles. Can valley pan or water pump fail after so few miles?

I'll keep you posted on what my mechanic says.

[Mr_E53]

Yep, I think I'll have to perform a pressure test.
I have inspected all the coolant related hoses and connectors, does not appear to be this.
I have also inspected the rear of the motor where the valley cover meets the heads and the valley, does not appear to be any seeps here either. Doing my head in at the moment.

Water pump area appears spot on.

[killcrap]

sounds like the valley pan gasket. if you are sure its okay, then possibly the rear coolant plate located behind the flywheel.

[Weasel]

Also check the gaskets of the coolant cross pipe that goes across the back of the heads. I've seen those leak down the back of the engine, and you can usually see buildup on the gaskets if they are leaking.

[Mr_E53]

Thanks "Weasel", I'll have to sus that one out. What's the easiest way to inspect the cross pipe? How to I get a reasonable view of it?