x5 M Coolant leak from Bell Housing

[bmwpower603]

Hello all,

I have recently noticed some coolant coming out of the bell housing. I have taken off the rubber plug; and let it run on my lift. I drove it for a while, then brought it back to put on the lift and inspect for leaks. No leaks found!

During this past week, I let the x5 sit for a few days. After the second, or third day, small amounts of coolant can be seen. I think if I cold start it for about a minute then shut it off; it will begin to leak once again..

I already what your thinking; rear coolant cover. The rear coolant cover was replaced by BMW in November of 2018, along with all the turbo coolant lines... I have recently done major services on the vehicle, this includes a new heater valve, water pump, some coolant hoses, valve cover, ect.

I have a borescope, but cannot really get a good view of anything close to the rear coolant cover.. My guess here would be that the cover has once again failed. Maybe due to improper cleaning of services at the dealership.

At this point, any kind of pointers would be helpful. I will try and get in contact with the dealer ship who serviced it. Maybe they can cut me a break.. That rear coolant cover should not be leaking already.

Is there anything else that could be leaking? Is there a hole , from the valley to the back of the bell housing? Maybe I need to take a look at the turbo lines?

[Sophisticated Redneck]

Originally Posted by bmwpower603

Hello all,

I have recently noticed some coolant coming out of the bell housing. I have taken off the rubber plug; and let it run on my lift. I drove it for a while, then brought it back to put on the lift and inspect for leaks. No leaks found!

During this past week, I let the x5 sit for a few days. After the second, or third day, small amounts of coolant can be seen. I think if I cold start it for about a minute then shut it off; it will begin to leak once again..

I already what your thinking; rear coolant cover. The rear coolant cover was replaced by BMW in November of 2018, along with all the turbo coolant lines... I have recently done major services on the vehicle, this includes a new heater valve, water pump, some coolant hoses, valve cover, ect.

I have a borescope, but cannot really get a good view of anything close to the rear coolant cover.. My guess here would be that the cover has once again failed. Maybe due to improper cleaning of services at the dealership.

At this point, any kind of pointers would be helpful. I will try and get in contact with the dealer ship who serviced it. Maybe they can cut me a break.. That rear coolant cover should not be leaking already.

Is there anything else that could be leaking? Is there a hole , from the valley to the back of the bell housing? Maybe I need to take a look at the turbo lines?

There is a weep hole in the valley on n63/s63's that will allow oil/coolant to run down back of engine and out bell housing.

Possibly your turbo coolant lines, pull your engine cover and inspect them. Also inspect the head to head coolant line that runs by the turbos and alternator. It has a plastic y built in that is notorious for cracking and leaking. BMW bean counter outdid themselves on that one. Great way to ruin a 30,000 dollar engine so they could save 50 cents on plastic over metal. Recommend you replace with new hose and metal Y like some of here have done if it's the culprit (my guess it is)

[bmwpower603]

The turbo coolant lines were replaced by bmw with the rear cover at 68k. Currently at 85k. The coolant hose your mentioning was recently replaced at bmw as well; along with the top hoses that run to the metal lines. That was done at 84,200. There was ALOT of coolant that got in the valley at the time.

BMW did mention that it would take a while to burn off the coolant in the engine. Could this still be residual coolant? Shouldn’t it have all burned up by now; and no longer be in liquid form?

[Sophisticated Redneck]

Originally Posted by bmwpower603

The turbo coolant lines were replaced by bmw with the rear cover at 68k. Currently at 85k. The coolant hose your mentioning was recently replaced at bmw as well; along with the top hoses that run to the metal lines. That was done at 84,200. There was ALOT of coolant that got in the valley at the time.

BMW did mention that it would take a while to burn off the coolant in the engine. Could this still be residual coolant? Shouldn’t it have all burned up by now; and no longer be in liquid form?

Valley can hold quite a bit of fluid but yes it should have all burned off/evaporated by now. Even though ther hoses are all pretty new, still possible they are leaking from a bad install, especially with the crimp fittings they love to use. I would pull your engine cover and inspect them closely.

If nothing is found then next step would be to check valley with your borescope to be absolutely sure old fluid is still somehow not trapped in there. If you pull off the turbo/cat heat shield (bit of a pain as must remove o2 sensors but not to bad to do), there is just enough room to sneak a borescope down the gaps in the drip tray by the rear cylinders and see the valley itself. You should see evidence on the drip tray too of fresh fluid.

If still nothing is found, then can't think of any other way coolant could get down in bell housing other then rear coolant cover. There are some heater coolant lines above bell housing in firewall but I'm sure you have already checked all that out.

[bmwpower603]

I took the turbo blanket + turbo heatshield off. I am having a very difficult time getting my scope under the tray at the rear to access the valley pan. Everything looked dry. There was a little but of coolant that is starting to dry up on the oil return line cover. It still had some color to it.. The rest of the engine is gunked with white dried up coolant.

Maybe the coolant leak was really bad before? Enough to make residual coolant come through the hole?

Is there any other coolant lines that come from the oil return cover? I am close to removing the turbos to get better access. But that would require removing alternator, and pulling up wiring harness a bit. I did notice the coolant in the expansion tank a little low. But I have not really monitored it since I replaced the heater valve. I wonder if I should keep driving it, or do more investigation.

[Sophisticated Redneck]

Originally Posted by bmwpower603

I took the turbo blanket + turbo heatshield off. I am having a very difficult time getting my scope under the tray at the rear to access the valley pan. Everything looked dry. There was a little but of coolant that is starting to dry up on the oil return line cover. It still had some color to it.. The rest of the engine is gunked with white dried up coolant.

Maybe the coolant leak was really bad before? Enough to make residual coolant come through the hole?

Is there any other coolant lines that come from the oil return cover? I am close to removing the turbos to get better access. But that would require removing alternator, and pulling up wiring harness a bit. I did notice the coolant in the expansion tank a little low. But I have not really monitored it since I replaced the heater valve. I wonder if I should keep driving it, or do more investigation.

No other way for coolant to get in there other then what we have talked about (save for a leaky head gasket but you would have much bigger issues to worry about of that was the case)Here is what I would do next: Fill (or remove) coolant so it is just barely above the Min notch in the expansion tank. This should be done when the engine is completely cold/at ambient temp. Then drive it for a good 20+ min, do a mix of idling/city driving/a couple of full throttle pulls all which tend to produce the highest coolant pressures. Stay close to home just incase something goes sideways.

The next day after the engine has completely cooled and when the ambient temp is the exact same as day before, check the coolant level. Even if you leaked even just a little fluid, it will show up being lower then the minimum as the expansion tank does not hold much fluid. If no change I would repeat it a few more times and if its not going down then its pretty clear it just old fluid working its way out.

[bmwpower603]

I checked the bell housing this morning to see if I saw coolant; there was not any. I then proceeded to start the car, and take a look. Still no leaks.

With the car off; I put the car up on the lift again; just to find a few drips..

Is the flex plates movement keeping the coolant from reaching the bottom of the bell housing while the vehicle is turned on?

I find it odd that as soon as I turn the X5 off, I see drips..

Ill be taking it to 3D Auto works here locally for a full diagnosis. Apparently whoever installed the rear coolant cover at BMW did a terrible job. (They probably refused to clean the mating surfaces)

[pearlpower]

Recommend putting coolant dye in the system, only takes 1/4 of the bottle and checking with a black light. But apart from what was mentioned, no other areas the coolant could come from. I had a very tiny leak which was not visible in the hoses, I could only smell it from time to time, coolant has that sweet smell to it. With the dye it was an easy fix.

[bmwpower603]

I have used the dye before. I think the blue coolant is plenty visible, and probably more visible than any dye and black light.

Tomorrow im scheduled to bring it to BMW where they replaced that rear cover. Ill have an answer tomorrow

[bmwpower603]

Originally Posted by Sophisticated Redneck

No other way for coolant to get in there other then what we have talked about (save for a leaky head gasket but you would have much bigger issues to worry about of that was the case)Here is what I would do next: Fill (or remove) coolant so it is just barely above the Min notch in the expansion tank. This should be done when the engine is completely cold/at ambient temp. Then drive it for a good 20+ min, do a mix of idling/city driving/a couple of full throttle pulls all which tend to produce the highest coolant pressures. Stay close to home just incase something goes sideways.

The next day after the engine has completely cooled and when the ambient temp is the exact same as day before, check the coolant level. Even if you leaked even just a little fluid, it will show up being lower then the minimum as the expansion tank does not hold much fluid. If no change I would repeat it a few more times and if its not going down then its pretty clear it just old fluid working its way out.

I have brought the vehicle to BMW who serviced the rear coolant engine cover. They really seem to think that it is NOT the cover. And perhaps it might be some freeze plugs on the back of the engine..

Does anyone know if these are replaceable? The technician said that BMW doesnt even mention these; and mentioned removing them, and applying locktite ? He said its unlikely; but has happened in rare cases..

[TwinSnailz]

There are no freeze plug. The block is aluminum.
If the valley is dry and it is leaking back there, the rear cap is the only thing.

Since you mentioned that you have a borescope available, snake it under the alternator and work it towards the back for any coolant leak.

[bmwpower603]

Originally Posted by TwinSnailz

There are no freeze plug. The block is aluminum.
If the valley is dry and it is leaking back there, the rear cap is the only thing.

Since you mentioned that you have a borescope available, snake it under the alternator and work it towards the back for any coolant leak.

I have tried snaking it in between water pump, and alternator.

BMW service bulletin says to go through the passenger side exhaust heat shield.

Im tempted to just pull the engine / tran and do everything. I know the oil pan gasket requires removed the chain for the oil pump. Which I’m a little worried about doing. But if I follow ista maybe it won’t be so bad. How difficult would it be to remove the trans, and replace the rear main/ coolant cover? I have a lift, but no trans Jack. I wonder what an Indy shop would charge? Like 16 hours?

[Ahmedbmwx6me71]

I need a help
I have x6m e71 2013 ,
I checked log error and found :"charging pressure control, boost pressure too low" 0030FF and 310B: Boost Pressure Control 2, Plausibility Fault.
what will I do ?