Help!!! Coolant leak through transmission

[quiqued]

Hi, I please need your help!
A few month ago the car overheated and I finally decided to change the main parts of the cooling system at 145.000.
I just changed radiator, expansion tank, expansion tank retainer and pipes, oil cooler thermostat, water thermostat, water pump with Stewart Components water pump, pulleys, belts and tensioners, upper and lower thermostat hoses, and filled with BMW blue coolant.
There's no visible leak on any of the changed components or other hoses but there's a huge leak coming down the transmission bell.

Any Ideas on what the problem can be?
https://uploads.tapatalk-cdn.com/20210503/647cd1196b916d3847d758aacd07a065.jpg

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[DeathTrap]

Coolant temp switch, heater core hoses and the plastic pipes under the intake manifold seem to be the only likely suspects. Maybe a freeze plug but I don’t remember if one is back there.


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[Will]

Is that coming from inside the bellhousing?

How bad was the overheat? These engines don't handle overheats very well.

[quiqued]

Is that coming from inside the bellhousing?

How bad was the overheat? These engines don't handle overheats very well.Yes from inside the bell.
Pretty bad overheat but it was leaking before that but unfortunately I don't know exactly from where.

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[quiqued]

Coolant temp switch, heater core hoses and the plastic pipes under the intake manifold seem to be the only likely suspects. Maybe a freeze plug but I don’t remember if one is back there.


Sent from my iPhone using TapatalkCoolant temp switch I just replaced too, heater hoses and pipes didn't but they don't show leakage.
Looking on realoem I saw two freeze plugs/lids in the back of the head, a mechanic I know said thats the problem but he didn't inspect the car yet.

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[Will]

Any check engine light / codes?

Maybe cracked block / cylinder head, or head gasket failed? There's nothing coolant related within the bell housing.

Edit: just saw your post about the freeze plugs on the back... take off the cabin filter housing and feel around. If it's wet you've found the culprit.

[quiqued]

Any check engine light / codes?

Maybe cracked block / cylinder head, or head gasket failed? There's nothing coolant related within the bell housing.How about the hoses that go from the radiator to the transmission?

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[Will]

How about the hoses that go from the radiator to the transmission?

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Those attach to the left side of the transmission.

Sounds like you have an AT. The only things within the bell housing for an auto transmission are the flywheel / ring gear, and torque converter.


The red tape is covering the in/out pipe connections:

https://lh3.googleusercontent.com/MOU_DQLRDuumtIa1xVZSXaoC7gVmsctll1BIiOu4Gxco7ImPVr WUeFjbY1ZoUV631NRlC6ccZ8ZuwYPh9BeCOISj11mDt037y_wb U04V34wwNxdL3csmihGY-v6Rt7NRAYn3waFYhpJXKC5Ewt81fzckOu6PN587WSYIfhskBvJ u0jHMygJRJmjwpKsVENJxjwaf3CLUk6k11V1zIdJhtr7VJdQXA tMNUdjT6FIC6sdI3nJ0gkjgUQQu3i2BupJ1qOYxd5jFKkaIena YOLKncoh1L3LkWPMt8a1-ZL7vz3vls8odAK9sIRjDEDZnz2sb9Qf4i5uI7G7n-Ek-rw2epKUs8NMLsOZc1XuyquEU6fDQz0sxFphQE4B1766a3KAJIC l9g0pKvUhBw1PngrCX2cJ1GC3zXRaMohGVSHYMW3J_H7ibzpLq Pr1Ns2nM3GpxYGb15o3UP-p7wMuwVnEsbWE70LEOiPwubpByc3OTZNokggVlR8zW9jsj7SAO K72ehieiXFID3AR_5YsQZwDwcCAHmnb4-eKdm2r43m1Ve5EuUj2g-OeUmWqqB0pfYD4FWPX8utTOJW-ZCLeUKojZbf9JldyXv8szAVlJk1GHRl8wHsG9u6WJ23Uf9PQoW 2303wCm5GtpjtWCWCsHljWEr_Q7jYinI1g=w640-h480-no

And from the parts diagram from RealOem (link (https://www.realoem.com/bmw/enUS/showparts?id=BD53-USA-04-2004-E46-BMW-330Ci&diagId=17_0150)).

[quiqued]

Those attach to the left side of the transmission.

Sounds like you have an AT. The only things within the bell housing for an auto transmission are the flywheel / ring gear, and torque converter.Can those hoses leak inside the transmission and get to where I have the leak?

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[Will]

Oh, maybe the hose / pipe leaking near the back of the motor and ingress into the bell housing via the starter-motor opening.

Edit to add: the starter is where the chain is attached in the photo, above. There's that coolant hose that curves back towards the front in that area.

[DeathTrap]

Oh, maybe the hose / pipe leaking near the back of the motor and ingress into the bell housing via the starter-motor opening.

This is what I’m thinking. The overheating scenario created enough pressure to take the pipes out. They are VERY fragile at this point.

The freeze plugs are probably more reliable than those hoses...


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[quiqued]

Oh, maybe the hose / pipe leaking near the back of the motor and ingress into the bell housing via the starter-motor opening.

Edit to add: the starter is where the chain is attached in the photo, above. There's that coolant hose that curves back towards the front in that area.Makes total sense.
I'm gonna check with a radiator pressure pump and a snake camera

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[quiqued]

Makes total sense.
I'm gonna check with a radiator pressure pump and a snake camera

Sent from my SM-G986U using TapatalkDo I still have pressure on the cooling system even if I remove the intake manifold?

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[quiqued]

Oh, maybe the hose / pipe leaking near the back of the motor and ingress into the bell housing via the starter-motor opening.

Edit to add: the starter is where the chain is attached in the photo, above. There's that coolant hose that curves back towards the front in that area.Do I still have pressure on the cooling system even if I remove the intake manifold?

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[Will]

Do I still have pressure on the cooling system even if I remove the intake manifold?



Yes. They're independent systems. I recommend new intake manifold gaskets for reinstallation.

[quiqued]

Yes. They're independent systems. I recommend new intake manifold gaskets for reinstallation.Thanks
I already bought the manifold gasket, cooling pipes on the side of the engine, throttle body gasket, oil separator hose, and planing on cleaning the idle valve and throttle body when I remove the manifold.

Do you think I have to do something with the CCV?


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[DeathTrap]

Thanks
I already bought the manifold gasket, cooling pipes on the side of the engine, throttle body gasket, oil separator hose, and planing on cleaning the idle valve and throttle body when I remove the manifold.

Do you think I have to do something with the CCV?


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If you are already in there...


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[quiqued]

If you are already in there...


Sent from my iPhone using TapatalkExactly.

Do I have to replace the CCV and all the hoses too?

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[DeathTrap]

Exactly.

Do I have to replace the CCV and all the hoses too?

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I would, personally. Especially if you don’t have any record of them ever being replaced. Make sure you grab the cold weather package CCV. I’ve heard it’s a little more robust.


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[quiqued]

I would, personally. Especially if you don’t have any record of them ever being replaced. Make sure you grab the cold weather package CCV. I’ve heard it’s a little more robust.


Sent from my iPhone using TapatalkEven if I live in Miami?

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[quiqued]

SOLVED!!!
The two plastic coolant pipes in the side of the engine were totally destroyed.

I replaced everything on the cooling system and vacuum system, cleaned throttle, idle valve and DISA.

The car runs like new!

https://uploads.tapatalk-cdn.com/20210523/bcf473e5b4d7d1d7b820a1075ee32197.jpghttps://uploads.tapatalk-cdn.com/20210523/c7ff12366e12bc3058432be2bc214311.jpghttps://uploads.tapatalk-cdn.com/20210523/3c9f2bcad97dfd0e7a700b7324159cda.jpg

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[BMWCurves]

Damn...glad you figured it out! Can you post the part numbers of the broken hoses?

[John in VA]

#s 6 & 8 are the hard plastic lines:
06 Water pipe (1) - 11537502525
08 Heater inlet pipe (1) - 11531705210
(#7 O-rings come on the new lines.)
https://www.realoem.com/bmw/enUS/showparts?id=BD53-USA-09-2005-E46-BMW-330Ci&diagId=11_2200

[quiqued]

#s 6 & 8 are the hard plastic lines:
06 Water pipe (1) - 11537502525
08 Heater inlet pipe (1) - 11531705210
(#7 O-rings come on the new lines.)
https://www.realoem.com/bmw/enUS/showparts?id=BD53-USA-09-2005-E46-BMW-330Ci&diagId=11_2200Exactly!

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[san]

How often do they go bad? I know cooling systems on the front of the engine fails like clock work every 100k but I haven’t seen anyone mention these.


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[John in VA]

How often do they go bad? I know cooling on the front of the engine fails like clock work every 100k but I haven’t seen anyone mention these.
I've owned my 2003 530i since 75k miles. Replaced all that same stuff in fall 2019 at 140k preventatively - most parts were original.

[johnrando]

Good news!

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[DeathTrap]

How often do they go bad? I know cooling systems on the front of the engine fails like clock work every 100k but I haven’t seen anyone mention these.


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My ZHP had over 170k before I replaced them. They were brittle and broke into pieces as I was removing them. I would say 150k would be a good interval. Or every other cooling system overhaul.


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[san]

I’m at 204k and haven’t looked at them. From what you’ll are saying, it’s way over due.


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[quiqued]

I’m at 204k and haven’t looked at them. From what you’ll are saying, it’s way over due.


Sent from my iPhone using TapatalkI'm at 145k but it's a South Florida car so it always runs in very hot weather, the pipes where totally burnt out.

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[Will]

Glad you got it sorted!

[quiqued]

Glad you got it sorted![emoji120][emoji120][emoji120]

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[PdZHP]

My wagon had 106 k on the engine when the hard hoses went out. My zhp coupe has 87k with no issues (crossing my fingers).