Internal Coolant Loss F15 X5 M50d

[talba]

Hey

My car has been losing coolant after about 100 miles. The light comes on, and the tank is quite empty.

I had it sent to BMW through a "friend" who works there and they claimed to have pressure tested it and there were no external leaks. So they apparently discovered that 3 seals had blown and changed them. They did a coolant flush, oil change and gave the car back to me

I've been https://9apps.ooo/ monitoring the coolant level every morning when cold, and I'm starting to see it getting low again.

The car had the EGR recall done a few months ago. Is it possible that the engine is building so much pressure in the cooling system that brand new seals can blow AGAIN in 100 miles of driving? Would there be any other signs to look for or are they BS'ing me.

Any help or guidance would be greatly appreciated

[Edwardsc1]

I have a 50i, so little bit different with respect to the engines, but I was having coolant loss issues as well, about as much as you are. I had to have my expansion tank replaced because there was a slight crack in the bottom of it, and I also had to have all my T-joint connections replaced as well because they were leaking.

Could also be a small leak in the radiator if there was a puncture from a rock, but that's probably not as likely.

Some of those plastic pieces begin to break after going through so many heat cycles over the years. I had my T-joints replaced with brass ones and have been good to.

[CatalinP]

Depending on how the coolant was replaced, it might take a while to get all the air bubbles from the entire system out. I would not worry unless the low level warning comes back.

[RED_Y_]

Wonder if this is a real user or a bot, got a URL to malware web site in the text.

[Mo5es786]

Originally Posted by RED_Y_

Wonder if this is a real user or a bot, got a URL to malware web site in the text.

This is definitely a bot post. I'm the author of the original post on Reddit, and actually came here this morning to post for advice and was quite surprised to see my initial post here

[Mo5es786]

Originally Posted by CatalinP

Depending on how the coolant was replaced, it might take a while to get all the air bubbles from the entire system out. I would not worry unless the low level warning comes back.

I would hope that BMW would have filled and bled the system properly. I initially thought this as well but over the last 3 days (+- 150km) it's gone from being just over the max line to below the minimum line this morning

[Mo5es786]

Originally Posted by Edwardsc1

I have a 50i, so little bit different with respect to the engines, but I was having coolant loss issues as well, about as much as you are. I had to have my expansion tank replaced because there was a slight crack in the bottom of it, and I also had to have all my T-joint connections replaced as well because they were leaking.

Could also be a small leak in the radiator if there was a puncture from a rock, but that's probably not as likely.

Some of those plastic pieces begin to break after going through so many heat cycles over the years. I had my T-joints replaced with brass ones and have been good to.

Did they discover the cracks by means of a pressure test? Another BMW had supposedly pressure tested the system over a few days and found no external leaks and they also tested the head gasket and found it not be leaking

[Mo5es786]

Just to give some insight on how this has developed

I bought this car used, had it serviced and the EGR Recall done, did about 5000km and then one day the low coolant light came on. There was fresh oil in the coolant and my mechanic said the oil cooler had failed and we changed it. I must have driven it for another month and the low coolant light came back on and there was residual oil in the expansion tank and it was dry. Topped it off, drove it for 3 more days and it happened again. At that point my mechanic took it to BMW and had it pressure tested while I was away. They said all is fine and gave the car back. I drove it for another 3 days and yet again the light came on and the tank was empty, filled it up and still noticed residual oil.

It got sent to a different BMW dealer, where it spent the better part of 2 weeks. It came back and they said they had changed the EGR seal, Oil Cooler Seal and OFH Seal and flushed the system. They said the seals had "blown"

The car was jerking on cold start which has stopped now so I'm attributing that to the seals actually having being defective. But the coolant is still leaking internally and nobody can seem to figure it out. I had been getting a burning smell only on a cold start in the mornings from the vents and that's still there (not sure if relevant)

[Edwardsc1]

Yes, the pressure test found the leak when the tank was cracked. They said they pressure tested the system again after replacing the tank and that all was fine, but it took less than a month for my plastic T-joints to fail after that, so I think some of them were probably leaking a little bit already.

As far as the other issues, I won't be able to give any insight as to anything with the EGR since mine is a 50i. I've never owned a diesel car so I'm not sure what temperaments those vehicles might have. With that residual oil and coolant loss, it would seem to me that some rubber/plastic component somewhere is cracked and leaking

[suitedcboy]

EGR coolers in general are well known to have leaks that start leaking only after the cooler has heated up to normal temp. They can leak into exhaust or the boost pressure is higher than cooling system pressure so they also can leak only when boost pressure is high into cooling system and overpressure and open relief valve in coolant tank cap. Is there any dried coolant residue on top of coolant tank? Another way to detect it is with a pressure gauge T'd into a coolant hose. The coolant pressure will jump higher instantly under hard throttle if the cooler leaks and is venting into cooling system