Same Same, but Different: M60 Intake Boot

[Sir Montalbon]

I found a small vacuum leak where the intake boot meets the throttle body on my '94 540iA, so I ordered a new rubber ring for it. In the meantime, I swapped another intake boot over off a '95 540i/6and noticed that there was no rubber ring like the other boot had. When I tried to swap the ring over, it wouldn't fit.

To make matters more confusing, both boots have the same part numbers. A quick Google scan didn't shine any light on the subject.

Anyone seen this before?

617855
617857
617858
617859

[tantumaude]

Was there ASC on both cars? Are both parts OEM insofar as you can see?

I can't see the pics at work so I'm shooting in the dark a bit...what's the part number?

[KVF]

They have the same part #... Oo
I’d love to hear an explanation for this one...


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[84318i]

What brand ? I've had issues with same part number parts but different brands not fitting the same (radiator / expansion tank cap being one).

[moroza]

BMW usually updates the part numbers for a new or different manufacturer, and any minor changes like that during production, but this looks like an exception. Does the gasket have the same ID as the smaller gasket-less boot?

[Sir Montalbon]

Both boots are OEM BMW parts.


BMW usually updates the part numbers for a new or different manufacturer, and any minor changes like that during production, but this looks like an exception. Does the gasket have the same ID as the smaller gasket-less boot?

Yes, it does. The gasket-less boot fits perfectly onto the throttle body. However, the car ran like crap with it on, so I switched back to the boot with the gasket for now. I feel like with no rubber gasket, the plastic boot on the metal throttle body won't form a proper seal with just a hose clamp keeping it all together.

I built a smoke tester a couple of weeks ago out of some incense, a paint can, an old MAF housing, and an airbrush compressor. I'm going to smoke test both this weekend and see how the gasket-less boot holds up. I'll update when I'm done.

[moroza]

Pics of your homemade smoke tester?

Check the boots for a production date.

[Sir Montalbon]

Pics of your homemade smoke tester?

Check the boots for a production date.

Ran the smoke test on both boots and was surprised to see the gasket-less boot held with no leaks and the car ran fine on a test drive. The boot with the gasket had hairline cracks around the perimeter where the hose clamp is positioned and leaked some smoke. It ran fine at speed but had an on-again-off-again rough idle at rest.

I'm going to order a new OEM boot to replace the cracked one. Curious to see which one shows up.

I'll try to check the production dates tomorrow. They are on both of them.

And here's my smoke tester. I tried to make it all professional using o-rings and grommets, but when that failed I went to town with the RTV.

**Pro Tip**
The top of a jar of German sauerkraut fills the MAF housing quite nicely.

617935
617936
617937
617938

[moroza]

It's even the checkered-blue-white Bavarian/BMW pattern! :rofl

[516SC]

Have you watched inlet manifold numbers?

[Sir Montalbon]

It's even the checkered-blue-white Bavarian/BMW pattern! :rofl
I wanted it to be as close to OEM as possible ;)


Have you watched inlet manifold numbers?
How so? I'm not sure I understand the question.

[516SC]

Last number was 9 and it is changed to 8.
Once i had 5 different inlet manifolds and same partnumber..