2003 x5 Coolant Leak

[Stmary001]

Hope smoeone can give me an answer to what is leaking coolant from between the bellhousing of the transmissiom and the rear of the engine. It not dripping on the ground when i park the vehicle just a thick sludge at the bellhuosing.But i have to add coolant to the expansion tank every two weeks or low coolant warning will appear in the instrument cluster.Guess it leak when i am driving.An answer to where it leaking from will be greatly appreciated.

[PersonaNonGrata]

A common culprit is the expansion tank itself. Try to trace the flow of the coolant although it could be tough to see. Many of us have had to replace the tank. I replaced mine and I could not find any obvious cracks but it was definitely leaking. I was having to top up coolant daily and there was quite a bit of coolant congealed on various parts below the tank.

It might not be your tank but if you decide to change it, I would change out some hoses, the cap, and the level sensor while you're at it.

[TriX5]

Your Valley Pan is probably leaking, I just replaced mine.

Other possibilties are the coolant return tubes, the rear coolant manifold or one of the hoses on the rear coolant manifold.

There are several threads and a DYI on how to fix it.


Good luck.

[flatlander]

Originally Posted by TriX5

Your Valley Pan is probably leaking, I just replaced mine.

Other possibilties are the coolant return tubes, the rear coolant manifold or one of the hoses on the rear coolant manifold.

There are several threads and a DYI on how to fix it.


Good luck.

Valley pan. The valley in the middle of the engine has a cover which is prone to leaking. When the coolant seeps out of the cover, it pools in the vee of the engine and can mostly evaporate, leaving you wondering "where did my coolant go??" If the coolant leaks enough it will drop out of two drain holes at the back of the vee by the firewall and then go down by the bell housing. I'm pretty sure that is what you are seeing.

Check the DIY for the valley pan repairs. The updated valley pan is relatively cheap ($11), but the repair is very labor intensive and you have to remove the intake manifold, water pump, coolant manifold, etc to get to the pan. It's a good opportunity to replace many parts that will commonly fail (water pump, thermostat, rear manifold gaskets, Oil separator, hoses, etc.

[Stmary001]

I have been investigating the leak and the position where it coming from and i have to agree with TRIX5 about the vally pan making a mess of itself. So now come my DIY and to know all parts to order before i started, seems like i got to move alot of things out the way.Thanks alot for the help so far.Question now is where to order parts from and get the correct items for the job.Any advise on that will be greatly appreciated again Thanks alot. Was driving me nutts!!!! trying to find just what the heck was leaking behind there.Was thinking heater core and was about to take that out. My location New York USA thanks.

[faranks]

Originally Posted by flatlander

Valley pan. The valley in the middle of the engine has a cover which is prone to leaking. When the coolant seeps out of the cover, it pools in the vee of the engine and can mostly evaporate, leaving you wondering "where did my coolant go??" If the coolant leaks enough it will drop out of two drain holes at the back of the vee by the firewall and then go down by the bell housing. I'm pretty sure that is what you are seeing.

Check the DIY for the valley pan repairs. The updated valley pan is relatively cheap ($11), but the repair is very labor intensive and you have to remove the intake manifold, water pump, coolant manifold, etc to get to the pan. It's a good opportunity to replace many parts that will commonly fail (water pump, thermostat, rear manifold gaskets, Oil separator, hoses, etc.

was just about to do my valley pan gasket and want to make sure that I get the right part. Is it #1 or #3 in this diagram?
RealOEM.com * BMW E53 X5 4.4i Engine Block Mounting Parts
I should have done it while I had the manifold off a while ago replacing those rear coolant hoses and valve covers.
Since this is a huge chore, can anybody suggest anything else while I'm back there again that probably should be replaced (140k).

Also, I remember looking at those two pipes that run above the pan and thinking that looked tough to get them out. Anybody have a preferred way to go? Maybe I should just replace the water pump a 2nd time and take them out the front?

Last question. I remember that hose coming out the bottom of the OSV being fairly pinched back there, wherever it goes. Important? I remember trying to assess what the OSV really does, 2 lines from the top of either head I believe and then the one hose that disappears below...

[rocksteadyX5]

Originally Posted by TriX5

Your Valley Pan is probably leaking, I just replaced mine.

Other possibilties are the coolant return tubes, the rear coolant manifold or one of the hoses on the rear coolant manifold.

There are several threads and a DYI on how to fix it.


Good luck.

Where can I find these DIY? I check the DIY, didn't see anything.

[papasmurf]

If it's a V8, definitely valley pan.

[petener999]

Originally Posted by Stmary001

Hope smoeone can give me an answer to what is leaking coolant from between the bellhousing of the transmissiom and the rear of the engine. It not dripping on the ground when i park the vehicle just a thick sludge at the bellhuosing.But i have to add coolant to the expansion tank every two weeks or low coolant warning will appear in the instrument cluster.Guess it leak when i am driving.An answer to where it leaking from will be greatly appreciated.

Check heater hose #11 and #12 first. See diagram below...

[Stmary001]

Ok thanks will check heater hose #11/12 also thanks for the diagram,and yes it is a 4.4i.