Coolant Leak Under the Intake Manifold
 

Hello Guys,

I know this is a well know issue and has been addressed in many threads, but I believe my issue to be different and would like confirmation before diving into this further.

2005 X5 4.8iS developed a coolant leak under the intake manifold in the form of coolant evaporating and dripping under the car.

Thinking that it's the common know issue with the valley pan cover or crossover pipe under it, I removed the intake manifold, only to discover a ton of coolant on top of the valley pan cover itself, and a broken Y fitting that joins 3 small coolant hoses. My dilemma is, that I'm not sure if the Y fitting broke while I was wrestling the intake manifold out, or whether the problem is really with the valley pan cover.

So the question is: Is there supposed to be coolant ON TOP of the valley pan cover itself (in the valleys of the valley pan cover)? If not, then I'm golden.

I have attached 5 photos:
- 1 showing the coolant on top of the valley pan cover (there was quite a bit more there, but I removed most of it)
- 2 showing the actual broken plastic Y connector
- 1 showing an intact connector and associated hoses (BMW P/N: 17127509967)
- 1 taken from realoem.com, showing the hose. The hose goes from one side of the expansion tank to the 2 cylinder banks.

Any help would be greatly appreciated, as it would save me a lot of time and grief!

Bringing this to the top please.

Coolant draining off the back of the engine is often misdiagnosed. Best practice is to remove the reinforcement plate and the splash shield and use a bright flashlight to trace the fluid to the highest point possible. Doing so, will eliminate places the coolant could be leaking from the front of the engine and flowing to the back of the engine to exit. If the front sources are not the problem you may be able to see back of the engine sources from below though it is necessary to remove the engine cover and cabin filter housing. Most of the time you will find the problem is a coolant hose.

My guess based the odds and the appearance of the hoses in the pictures the source of the coolant leak is the broken hose. though I can't tell by picture how much could drain from the the break. To be sure of the source you would have to pressurize the system.

Since you already have the intake removed you may want to be safe rather than sorry. Either way it is a good time to replace at least all the hoses in that area while you have easier access.

My take
 

My Indy just did my 2004 4.4 coolant pipe.
He said those y pipes ALWAYS break when removing intake.
As for your coolant leak can't say for sure the source.


IMO you might as well continue with the collapsible replacement coolant pipe
now. If it's near 100K, it's done. Not a cheap repair, but it's a one and done
modification. You are 3/4 of the way in there.

Thanks you guys for the quick reply. One question I am trying to have answered is: Would there be coolant on TOP of the valley pan cover if the Y connector WAS NOT broken?

Unless I'm missing something, I'm not seeing how coolant would end up there.

Since you have coolant on top, I can't perceive how it would get there
UNLESS the Y pipe was compromised.

What is your repair plan?

Could be valley pan gasket but coolant pipe leaks that are not unusual are far more likely and coolant does collect on top of the valley pan.

https://www.ecstuning.com/b-uro-part...N1sBoCqA_w_wcB

Popular wisdom and common sense dictate that since I'm already in there, is to replace the valley pan cover, coolant pipe & even the water pump.

Two things working against me right now: time and money. This is my wife's daily driver and it's been out of commission almost going on 2 weeks now, so it's time to button it up. Add to that 2 Land Rovers at home that also need some attention, so the decision is to just replace the broken hose assembly at this point in time. I will have to tear through the engine soon enough, since the valve guides need replacing, at which point I will replace the valley pan cover and W/P.

I have earlier today bought the new hose assembly, intake manifold gaskets, throttle body gasket and 2 VANOS O rings (original BMW parts all), and will put it back together and back on the road.

Anything else I should do/replace while I'm there before putting it back together?

Put it back together, and everything went smoothly. I fired it up and the coolant leak is fixed, but I now have another issue:

When it was idling, it misfired and the CEL came on. Pulled the codes, and found many due to misfires and a "main" code about the cam position sensor.

I made sure everything was plugged back in before I fired it up, what am I missing? Is it possible to mix up the connectors?

What does it matter anyway. At this point you should really be considering doing a cooling system upgrade repair due to the age of the vehicle and the fact that you have leaking coolant. Don't try to fix what you think is the one leak button it all back up to find out that an another leak persists. Just take the path of peace of mind and do the cooling system maintenance. There are countless accounts of folks with the 4.8is and coolant leak problems. All of which can be solved doing the cooling system maintenance.