4.8i - Potential Coolant Leak Paths

[onebad7up]

I have recently replaced the front coolant hoses, thermostat, water pump and sensors. There are no leaks at front of the engine, but I am noticing a drop coming off the rear of the engine whenever it sits for a while.

What other potential leak areas can I look for? anything on the top/rear of the engine?

[gregg3gs]

that is easy. valley pan gasket.

The best way to figure this out is remove what you need to pull the throttle body. Other than a little coolant vent pipe that runs from bank 1 to bank 2 sides of engine the valley pan leaks most often. So, if you are going that deep you might as well replace the mid engine coolant exchange pipe.

Here is the diy I did a while back.

http://www.xoutpost.com/bmw-sav-foru...-n62-4-8l.html

[jfoj]

As mentioned, valley pan.

Rear coolant passage cover, not a fun one.

See pictures in this link - BimmerFix Products | BMW Coolant Pipe Repair System

[khwahwa]

Maybe heat exchanger / Tranny oil cooler?

[X5Tim]

I have the same issue. Would some sort of stop leak be insane? I'm just trying to squeeze another year out of this '07 with 200,000 miles on it.

[Baby Unicorn Taco]

There is a "rear cover" at the rear of the engine. It is known to leak coolant and drip down the bell housing of the transmission. You can see if this is the leak pretty easily. There are 3 black caps on the bottom of the bell housing. if you pop one off you can see inside or feeling with your finger.

As for the stop leak idea. Don't do it unless you plan on just driving it into the ground. It will ruin other components.

[X5Tim]

Thanks, the value of the car is only about $3000, despite it being a very nice ride. People can't believe it's 12 years old. I was thinking one of the aluminum powdered like Barr's that works with Blue coolant and isn't supposed to clog even though it doesn't stop big leaks. Mine leaks about a quart every 3-4000 miles. Something to soften rubber seals might be worth a try. I'm just not willing to spend another $2K on a $3K car. Thanks again for the response.

[Baby Unicorn Taco]

Originally Posted by X5Tim

Thanks, the value of the car is only about $3000, despite it being a very nice ride. People can't believe it's 12 years old. I was thinking one of the aluminum powdered like Barr's that works with Blue coolant and isn't supposed to clog even though it doesn't stop big leaks. Mine leaks about a quart every 3-4000 miles. Something to soften rubber seals might be worth a try. I'm just not willing to spend another $2K on a $3K car. Thanks again for the response.

Find the source of the leak and then report back. A lot of these coolant repairs are not difficult, just time consuming. I just finished a bunch myself.

[ch4pz]

For anyone in similar sitcho, its probs this, i think mine is next


https://www.youtube.com/watch?v=F_gjFZJbAoE

[bcredliner]

If you haven't--- good idea to get under the vehicle with a bright white flashlight with a narrow beam and trace any indication of a leak to the hight point possible. Leak exit points can be very misleading. If you have recently replaced coolant components check your work first.