2002 BMW 530i What is this part ???

[texasbmw530i]

I recently removed the intake manifold on my 2002 530i to replace the heater coolant pipes. (A pain in the butt job.)

While putting everything back together I found one of these sitting on the lower part of the engine block
and another one on the floor under the engine.

Both the parts man and the service manager at my BMW dealership had no idea what it is.

Can anyone identify this?

mystery part.jpgpart 2.jpg

[dtw]

It is one of the fastener guides for the intake manifold. Looks like they fell out when you removed manifold and/or when you reinstalled with new gasket.

[texasbmw530i]

Thanks for the reply but .... what is a faster guide, and where was it suppose to go?

[dtw]

I don’t have a manifold on the shelf or I would just shoot a pic. Think of the studs on the head, onto which the manifolds slides. Some of the studs pass through these guides.

The guides also function to compress the manifold gaskets in these areas. It may be that without these in place, you rapidly develop intake leaks. Hopefully someone can weigh in with a pic so we can analyze the potential for leaks.

[texasbmw530i]

Intake manifold fastener guide? Where is it on this picture?

intake manifold.jpg

[effduration]

It sits in the manifold under the red gasket..I think they go under the smaller round holes in the gasket. They commonly fall out...

[orientblaumet]

There are 6 of those and the are a part of the ICV (Idle Control Valve) system. Don’t lose those, your engine will not run very well without them. Not available to buy, you would have to get another used or new intake manifold or find someone that would part them out for you.

[texasbmw530i]

OH THAT'S JUST GREAT !!!!

I've had to remove my intake manifold twice in the past 18 months for leaking heater coolant pipes (lesson learned use genuine BMW parts).

I researched the details of this process over and over and in great detail online prior to doing the job .... and NOWHERE ... NOWHERE ... was
it ever mentioned that there are 6 little pieces that are free to fall out of the manifold. UNBELIEVABLE !

Member Orientblaumet states that you can't buy them and the car won't run very well without them. Great, just GREAT ! So what exactly do they
do? I found 2 of them under the car when I finished the job about 2 months ago and the car seems to run and idle just fine.

Do they absolutely need to be there or is it a belt and suspenders kind of deal.

plugs.jpg

Please don't tell me I don't really have to go through all trouble of pulling the intake manifold just to put those 2 %$#! back in.

[seagreen323i]

Just turn it on and feel it out, you won't lose anything by doing that. The passageway is still there, it just might not seal the gasket properly.

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[texasbmw530i]

As I mentioned I finished the job about two months ago and haven't noticed any difference,

I ask again, what exactly are those plastic tubes there for? What do they do? What are they called?

I feel like BMW blindsided me again ... argh ¡¡

[seagreen323i]

There is a small port in the cylinder head separate of the main intake port. That little plastic peice funnels air into it. That is how the idle control valve gets the air to the cylinder instead of using the main runners.

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[Twistytee]

There is a small port in the cylinder head separate of the main intake port. That little plastic peice funnels air into it. That is how the idle control valve gets the air to the cylinder instead of using the main runners.

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^^^This.

Those are called turbulence ports and act to help channel idle and low speed air from the ICV to the intake valve of each cylinder. I believe the OPs photos are the inserts designed like a reducer valve to focus a high flow rate of air which then joins the intake runners at the intake valves to help reduce turbulence/intake fluctuation and stabilize combustion. The ports are described in the Bentley but there’s no mention of the inserts. As you’ve discovered, your engine will run without them but it will presumably idle rougher and likely be less efficient on fuel. They’re also not sold separately from the intake manifold so you’d have to scavenge them from a used manifold if any are missing.

[seagreen323i]

In all honesty, it will run fine like you've discovered. The ecu will adjust for the minor change in flow. Frankly there are hundreds of e39s and e46s out there that probably have lots of carbon build up in those ports effecting airflow and the oblivious owners are non the wiser.

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[texasbmw530i]

Thanks to all of your replies. I NEVER would have figured this out without all your input.

I finally found a picture of the intake manifold without the gasket and sure enough there is the offending article(s)

intake plug.jpg

Since the car seems to be idling normally I'm not going to lose sleep over this, but it really looks
like the plastic plug aids the manifold gasket in getting a proper tight fit.

Thanks again for all your help !