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Discussion Starter #1
Hello, i am new to the forums, just recently picked up my 2002 beast. I am not new to the BMW world as i came from the E90/E92 Forums.
I will Soon post pictures of my new Beast!


I am in need of some help/experiences. When i bought my car is was leaking oil and coolant. I was able to find and fix my oil leak however the coolant leak is a bit odd to me.

I found the source of the coolant leak however i don't know what its doing there.
It is dripping from INSIDE the corrugated wire of the Oil level/temp sensor connected to the oil pan.
i can actually physically see it dripping from the sensor but not interrupting the connection of the sensor (still works properly)
I tried following the wiring up but i can only go so far. Before i start removing everything in the way i thought maybe someone oddly had the same issue?


Thank you!
 

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Discussion Starter #4
Coolant will drip everywhere down the front of the engine and below. Sorry, but you're going to have to take off some parts to see where the source of the leak is located.
yes this is what i plan to do but i thought i would ask if someone had it drip from the same odd spot before. its literally dripping from inside the oil level sensor wire.:Thumbdown:
 

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Discussion Starter #5
check sensor in bottom radiator hose, the oring may leak after being disturbed.
seemed like a very good idea. just went to check it out and it seems pretty dry around that sensor. Seems like it is leaking from somewhere then going INTO the oil level sensor wiring and following it all the way down. Ill try to post some photos soon
 

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yes this is what i plan to do but i thought i would ask if someone had it drip from the same odd spot before. its literally dripping from inside the oil level sensor wire.:Thumbdown:
I wouldn't give too much weight to that spot unless it's the only place it's leaking from. Coolant leaks can spread around quite a bit with time. Unfortunately, the vibration damper blocks most of the view under the water pump and the thermostat blocks the view from above.
 

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Do you know if any work was done on the cooling system recently?

I would start with the hose connections at the pump and thermostat. Next the O-rings from the T'stat housing, and then block-off plate at the back (flywheel side) of the engine.
 

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Take off the plenum (completely). You now have access to the top of the block. If you can't see the leak there you are probably in deep do-do since the only other natural locations would be the water pump of plugs, and these don't usually leak unless there was a repair done.

d-
 

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Discussion Starter #9
thank you for all the replies! ill be taking my plenum off this weekend and going on an investigation! ill let you know what i find
 

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Discussion Starter #10 (Edited)
here is where the coolant is leaking from. following that wire down from outside and inside.

(this is the oil level sensor wire on the oil pan)
 

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Anti-freeze looks green, not original. I would suspect the system has been serviced because of the non-original anti-freeze. I would rent a pressure tester from your local auto parts store to help find the leak(s). I would also consider switching back to BMW anti-freeze after you fix the leak(s) and complete a complete system flush.
 

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Based on your photo, I suspect the coolant is traveling down the corrugated wire sheath and dripping off of the oil level sensor on the pan. If you track that wire sheath you'll find that it travels up just to the left of the thermostat and meets a connector just below the entry point of the right air intake tube where it meets the plenum. On my car that wire sheath runs right next to and touches the coolant hose right where it meets the thermostat. This is the large coolant hose connecting the thermostat to the lower radiator opening. Check to see that the hose clamp is secure and coolant isn't weeping from this point.
 

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Discussion Starter #13
Based on your photo, I suspect the coolant is traveling down the corrugated wire sheath and dripping off of the oil level sensor on the pan. If you track that wire sheath you'll find that it travels up just to the left of the thermostat and meets a connector just below the entry point of the right air intake tube where it meets the plenum. On my car that wire sheath runs right next to and touches the coolant hose right where it meets the thermostat. This is the large coolant hose connecting the thermostat to the lower radiator opening. Check to see that the hose clamp is secure and coolant isn't weeping from this point.

Very helpful, this is exactly what I was looking for.
As I expected it was traveling down the corrugated, just didn't know where that wire sheath lead to, haha.
Thank you ill be checking it out today!
 

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Discussion Starter #14
found the problem! turned out the rubber seat on the thermostat was torn up. ordered a new thermostat hopefully should fix the problem.

Also, replacing the O rings while im there for the thermostat housing.
 

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found the problem! turned out the rubber seat on the thermostat was torn up. ordered a new thermostat hopefully should fix the problem.

Also, replacing the O rings while im there for the thermostat housing.
Not to be problematic but there is no rubber seat on the thermostat - sounds like someone tried to use a gasket material of some sort, which is a bad plan.

There are 6 rubber o rings. Order 12 to be safe if this is your first thermostat repair.

D
 

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If that seal was torn up, you need to think long and hard about how it might have happened before assuming it is your issue. That seal never gets touched during or after install, so there really is no reason why it would ever wear out.

d-
 

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Discussion Starter #20
So while i am waiting on my new thermostat and o-Rings, i went ahead and drained all my old (green) coolant from the previous owner.

drained from Radiator and BOTH drain plugs on the block. I want to go ahead and flush and clean out the system of all that old coolant. anybody can help me out on how to do that on our cars. I know i need distilled water to clean it out but im not completely understanding how its done after watching/reading everything on coolant flushing.
 
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