What is this and how do I fix it?

[RandyBMC]

http://i39.tinypic.com/mkvr86.jpg

I was driving my 2001 E38 740iL today and steam started coming through the bonnet vent, followed shortly thereafter by the check coolant warning. Never exceeded temps. I've done the valley pan gaskets and numerous other fixes. The leak is at the block that these three hoses connect to - it looks cracked. What is this piece and how do I fix it? Is it the heater core?

Thanks in advance!!

Randy

[PiotrC70]

I'd say run the engine to temp and pop the hood looking for steam. My guess is either the "coolant transfer pipe" on the top back of the block which has 2 paper gaskets on either side. This is also the same coolant transfer pipe that has the big/small aluminum pipes going into it for the water pump. If not that, then one of the many coolant hoses on the back of the block.

[oldroller]

Randy, that is the pipe connection to the heater core. It leads back into the IKHA unit and secures to the heater core.The pipes are a separate part, connected to the core via screws and O-rings. Those two hoses should be clamped, I assume you removed the clamps? If the piping is cracked at the block that the pipes are part of, it will need to be replaced. I know of no repair for a cracked pipe to block junction, maybe others have been there before and can chime in.If the pipes need replacing, some under dash disassembly will be necessary. Never had one out, looks intricate.

[RandyBMC]

That's not my car - it was a photo I took while looking to figure out what was back there. I think it was in the middle of an assembly. Mine all have hose clamps. Looking at the parts diagrams, I see that there isn't really a block there, just hard lines. Those hard lines lead to the heater core inside the cabin. This leak (that I have) is definitely at the rear of the engine in the engine compartment. I'm guessing it must be one of the hoses and there was a jet of steam that made it look like the steam was coming from that area. I'm thinking it best just to replace all of the rear coolant hoses. Suggestions welcome!

[Ruskii]

Hopefully it's just one of the rubber hoses (would make more sense) than the metal piper (less likely). I would suggest replacing all of those hoses in the back - should be 4 of them. Also, you've mentioned replacing valley pan gasket -- did you get to it by removing the water pump at the front of engine or the accumulator pipe in the back of the engine?

[RandyBMC]

Yeah thanks - I ordered all four yesterday, so hopefully it will be one of the hoses. I did the valley pan when I replaced the knock sensors a while back (maybe a year or so ago). I had the whole top apart with the manifold off. It ran like a top until yesterday (still runs fine, just have to deal with the leak). Appreciate the suggestions!

[Ruskii]

Yeah thanks - I ordered all four yesterday, so hopefully it will be one of the hoses. I did the valley pan when I replaced the knock sensors a while back (maybe a year or so ago). I had the whole top apart with the manifold off. It ran like a top until yesterday (still runs fine, just have to deal with the leak). Appreciate the suggestions!

The reason I asked is if you removed the rear accumulator, I hope you replaced the two paper gaskets. If you didn't, might as well replace them too while you are there replacing the hoses. Also, check your heater valves for busted grommets -- easy fix for $12.

[Mayorchuck]

Every E38 I have owned has had one of these hose split.