Coolant leak, help to find part number

[Bmw_6]

Hi all,


I have a coolant leak, this is the only place I can see sign of a leak. I am not sure is the leak coming from the end of the hose or the part where the hose is attached is leaking. It is F12 650i.

Anyone knows what is this part where the hose is attached to? The location is on the left driver side, front of the car behind horizontal bar, top of the radiator.

Thanks

[Opie55]

What year car? It may matter because 2012s were different under the hood in many respects.

[Bmw_6]

It is 2012 650i

[Opie55]

OK, I looked at my 2015 F12. That is not a separate part. It is part of a rather complex coolant hose assembly. I'm 98% sure the part number you need is 17127595252. Google that number and you'll see what it looks like. It runs about $150. To confirm the number for your car, enter the last 7 places of your VIN at RealOEM.com and click on "Browse Parts" then click on the radiator icon and then the coolant hoses drawing.

[Bmw_6]

Thanks Opie55,

Yes it looks like that might be included with hoses in part 17127595252, but I was not sure.

Do you know are there any instructions how to replace this part? Is there a service manual that we can download for our car?

I wonder is it easy to replace myself, this part is accessible, is it just screw in to the radiator? Bottom end of the hose might be difficult to reach since there is so little space and hard to access.

Thanks

[Opie55]

No, there is no downloadable manual. It can be difficult to locate precise instructions for replacing something like that, even within BMW's own system. The short answer to your question is no, it is not easy. Even for an experienced DIY person it would be somewhat of a pain. At a minimum I'm sure you need to remove the fan and fan shroud, for example, just to have room to work. But I sense you are not an experienced DIY person. I think you would regret trying this, to be honest. Then you will also need to learn the steps to bleed a BMW coolant system. To answer your specific question, that one part of the complex hose assembly does not screw to the radiator. It has a clip that you slide out a half inch or so, then if just wiggles/pulls off. It is sealed by an O-ring inside. It goes on the opposite - you press it on to seal the O-ring, then press the clip back in. But then you have about 4 other connections to make, which use different methods.

[Bmw_6]

Thanks Opie55, yes, I see it is difficult. It is usually easy to do it, but on this car there is no room to access the bottom end of the hoses. At minimum you need to remove the fan assembly. Correct me if I am wrong, but I think bleeding the system should be no problem since there is electric auxiliary water pump and bleeding procedure.

I have an extended warranty and It will probably go to service. I have very bad experience with the service here so I try to avoid that and make sure I know exactly what is wrong before I leave the car.

Couple of questions:

The engine was replaced recently under the recall. Is there any way to know for sure if the water pump and thermostat are new and came with the new engine or they used old ones? I saw some posts that they might reinstall pumps from the old engine, not sure if that is true, that would be crazy.

Do you know is it ok to use leak detection dye in the cooling system and which one? In example Auto Pro USA Antifreeze and Coolant Leak Detector UV Dye, not sure is it ok to use with BMW coolant. I want to make sure there are no other leaks. I checked with a small camera and I do not see anything else.

I am really pissed and surprised they reused old hoses without telling me. As far as I can tell only turbo hoses are new. Hoses are pretty inexpensive from BMW, if I knew that I would buy all new ones to be replaced when the engine was replaced.

Thanks

[zanye08]

Originally Posted by Bmw_6

Thanks Opie55, yes, I see it is difficult. It is usually easy to do it, but on this car there is no room to access the bottom end of the hoses. At minimum you need to remove the fan assembly. Correct me if I am wrong, but I think bleeding the system should be no problem since there is electric auxiliary water pump and bleeding procedure.

I have an extended warranty and It will probably go to service. I have very bad experience with the service here so I try to avoid that and make sure I know exactly what is wrong before I leave the car.

Couple of questions:

The engine was replaced recently under the recall. Is there any way to know for sure if the water pump and thermostat are new and came with the new engine or they used old ones? I saw some posts that they might reinstall pumps from the old engine, not sure if that is true, that would be crazy.

Do you know is it ok to use leak detection dye in the cooling system and which one? In example Auto Pro USA Antifreeze and Coolant Leak Detector UV Dye, not sure is it ok to use with BMW coolant. I want to make sure there are no other leaks. I checked with a small camera and I do not see anything else. Honestly the hardest part was dealing with messy coolant, very hard not to make a mess. Correct on running the bleed procedure..I was able to kick it off with ISTA+

I am really pissed and surprised they reused old hoses without telling me. As far as I can tell only turbo hoses are new. Hoses are pretty inexpensive from BMW, if I knew that I would buy all new ones to be replaced when the engine was replaced.

Thanks

I have done this replacement..it's not too bad, you need to remove upper support struts, support plate, radiator fan , take the front drivers wheel, and the plastic panels, to get access to water pump. Its worth it to save almost 2000 dollars BMW wanted..in the end its just removing bolts and hoses...there was a guide somewhere...If I find it I will post it...

[FlyinLowSD]

Originally Posted by Bmw_6

The engine was replaced recently under the recall.

Just thinking aloud here, so to speak. Seeing as the engine was recently replaced, then these hoses were disconnected and reconnected. Unless you are seeing an actual crack, it is possible that the O-ring Opie55 mentions was either left out, reused and therefore is not sealing adequately, was not seated correctly so it’s not sealing correctly, or, or, or.

Bottom line it could be as simple as replacing an O-ring right there. You might save yourself some time and your warranty deductible by disconnecting at that location as described and inspecting the connection and the responsible o-ring. Plenty of YT videos on draining and refilling coolant then bleeding the system.

Maybe you have a buddy or someone in your car club who wouldn’t mind stepping through this with you?

Keep us posted!

An aside: because O-rings are what got me interested in aerospace and mechanical engineering as a teen in the first place, I feel the need to say Rest in Peace to the crew of the US Space Shuttle Challenger.

“Quoting aviator and poet John Gillespie Magee, [President Ronald Reagan] said, “We will never forget them, nor the last time we saw them, this morning, as they prepared for their journey and waved goodbye and 'slipped the surly bonds of earth' to 'touch the face of God.’” ”
- https://www.nasa.gov/feature/35-year...r-and-her-crew

[FlyinLowSD]

Some similar posts on other BMW coolant pipe o-ring:


https://www.e90post.com/forums/showthread.php?t=1028490

https://www.bimmerforums.com/forum/s...pe-o-ring-help

Edit: And a shout out to Nathan’s BMW Workshop. Here he changes out the coolant hose o-rings on a 4.4l M62tu. Great education!
https://youtu.be/DRhIroVWoRY?si=V-jBcsrTwknFFlxs

[Opie55]

I don't think there is an issue using dye, and any for that purpose is probably fine. I've never used dye. But you had a separate thread on the leak itself and it looked like a river if I'm remembering correctly. What you have at that joint just looks like dried up weeping. But if it were a big leak, you should be able to see it with a small mirror and the car running.

[Bmw_6]

Thanks everybody. Zanye08, I would appreciate if you find a guide to post it here.

FlyinLowSD, are you talking about O-ring between radiator and the metal part on the picture where the hose is connected? Do you know what is the part number for the-O ring and is it available to buy separately?

Oppie55, I never had any leaks before, this is the first time. The leak is very small, after 2-3 weeks coolant level goes from Max to Min in the main reservoir. I see whitish dried deposit on the metal part where the hose is connected in the picture. Last couple of times it looked dry after short drive, so not sure is the connector to the radiator (O-ring) leaking or the side where the hose is connected. I cannot see any other leaks that is why I was asking is it ok to use leak detection dye.

Here is how I discovered that there is possible leak, I heard like water gurgling and kind of like drilling sound After I turned off the engine after short drive of about 2 miles. I didn’t hear anything when the engine was on. I turned back the engine just for a sec to verify the engine temp and it was normal. Coolant level was at the min. I added coolant to the max and this noise stopped. After 2-3 weeks coolant is again at the min. Since the drilling noise was with the engine off it means that electric water pump was running. Is the issue maybe related to electric water pump and do you know how to verify that? I just cannot see any other leaks except on the part on the picture.

[FlyinLowSD]

Bmw_6 , I suggest you watch the video I posted by Nathan’s BMW workshop. He shows the equivalent of that hose among several others, and where the o-rings are, then proceeds to replace all of them with excellent explanations. Based on that you can determine if that looks like what you’re dealing with. I believe he also discusses how to measure an o-ring, and describes the kit he uses for most of his replacements. The o-ring is inside the hose connector where it connects to the metal part in your photo. Is for sure most likely culprit. Common issue.

⭐️ By the way, it is very helpful when posting photos if you post one zoomed out, circling the area of interest, then also post the zoomed in photo. That way we get a better idea of the area of interest. Good luck!

[Bmw_6]

I finally found where the small leak is, the coolant reservoir is leaking at the seam, it is very small leak and I missed it initially.

Anyone knows the part number and if somebody posted diy, if you have a link I would appreciate to post it here. I couldn’t find it on the forum. This is for N63 and coolant reservoir is at the front, left side above the wheel, not at the firewall.

Thanks everybody.

[FlyinLowSD]

Originally Posted by Bmw_6

I finally found where the small leak is, the coolant reservoir is leaking at the seam, it is very small leak and I missed it initially.

Anyone knows the part number and if somebody posted diy, if you have a link I would appreciate to post it here. I couldn’t find it on the forum. This is for N63 and coolant reservoir is at the front, left side above the wheel, not at the firewall.

Thanks everybody.

Good find! Congrats on tracking it down.
You can find the part number by searching realoem.com

In this case, if it is a small, accessible seam leak, you may consider repairing with WaterWeld by JB Weld. Plenty of YT videos saying that that worked for them.