choc545

Hello all,
Just bought an '04 545i with 96k miles. Car has been very well cared for. Unfortunately just got back from vacation and found a puddle of antifreeze on the garage floor. I checked the expansion tank, hoses, etc but turns out it looks to be coming from this part located near the front of the engine on the passenger side. The picture is taken from underneath the car shooting up. Anybody help me with what this part is and why it would be leaking antifreeze? I really hope this isn't the dreaded transfer pipe leak. Over the 6 day vacation the entire resevoir was drained so it's a pretty major leak. The car just sat the entire time. Any help would be greatly appreciated!!

BTW the light red circle is where the coolant is leaking.

Thanks

healthservices

Look at this how to to see where the coolant normally leaks if it is from the coolant pipe or if it is from the water pump weep hole.


http://forums.5serie...y-bmw%E2%80%99/

choc545

Thanks for the link. Great write up. Unfortunately the weep hole is dry. Starting to get concerned.

Without having to take off the water pump, any idea of where I would see an leak if the coolant transfer pipe is bad? Or said a different way would I see a leak externally if the transfer pipe is going?


Thank you!

turboawd

did you check to see if the coolant is running down from up above? i'd spray some brake cleaner and get everything clean, and then run it a bit maybe, and try to see where the leak starts.

usually if you have a bad pipe, it will seep out of the hole on the timing cover. there is a pic on this site that shows where. http://bimmerpipe.com/

dawid_w

Hi,

At this millage it is best practice to replace water pump, thermostat, coolant tank, temp sensor and all the hoses. That would be the best place to start.
I learned it the hard way that it is waste of time to wait and replace one thing at the time.

545i has few common coolant leaks:

1. Vent pipes
2. Coolant reservoir
3. Temperature sensor (on the lower radiator pipe)
4. Valley pan,
5. Water pump
6. Thermostat,
7. Of course ?weep hole?

healthservices

If it is not in the weep hole in the block

The other stuff is a cake walk.

toyota2bmw

+1 Between you and I, I think we plugged all the holes on our 545s.

e6t.lab.rat

The part with the threaded hole is for an optional mount of a belt tensioner, I believe for the ac compressor.

If your expansion tank was completely drained, odds are you have a cracked tank or broken vent pipes that are leaking fluid down on to the location you identified. Since your expansion tank is empty, now would be a good time to remove and inspect for cracks. Good luck.

choc545

Just wanted to give an update. Like I mentioned the car sat for a week and completely drained the expansion tank. The leak was defenitely coming from the weep hole in the timing cover (probably transfer pipe issue). So, I filled it up with OEM coolant to drive until I could get it to the dealer. The previous owner hadn't used OEM blue so I ended up mixing them but didn't care because I knew I planned to drain it all anyway for the repair. I started driving the vehicle daily and the leak quit. Nothing anywhere. I took it to the dealer and they presure tested it and found nothing. System was as tight as a drum.

My only thought is I have a seal that for some reason swells up with heat and closes the gap/leak. Could the coolant type have anything to do with it? I'm going on vacation in mid August for a week and it will be interesting to see if it does it again. More to come.

Thanks for all your help.

tiagul

Even with a small coolant leak you can quickly lose enough coolant to cause overheating and damage to your engine. Because your cooling system maintains a pressure of 15 psi during engine operation, it is possible you?re losing coolant only when the engine is running and shortly after until the pressure is lost through the breech. Tracking down your coolant leak can be tricky.You can consult with the water leakage detection service providers in that case.