exposing vacuum lines behind M54, to find a mystery leak

[workingonit]

Ok, the weather is about to get cooler around here in N.Texas, and the X5 and my other cars/trucks have either passed inspection (X5, GMC, Lexus, Chevy 2500HD) or will, later this month (HHR Panel... it tests OK per my Foxwell). Side note: It gets sorta expensive, all my vehicles needing inspections and registration renewals in Sept., Oct., or Nov., especially if I need to do repairs to make them pass.

Now's the time for my annual (or more frequently done) "search for the mystery vacuum leak" on my X5. The fuel trims are always on the lean side, and I'm regularly cleaning and/or resetting the MAF sensor, to prevent P0171 and P0174 from setting a CEL. Long term trims are always above zero, and slowly climb (unless I'm on a super-rare, extended...20+ mile, highway run).

This year, I'll delve deeper into the bowels of my engine bay, by taking apart the plastic microfilter housing and associated crap covering the rear of the engine, since I can actually park the X5 in a garage bay (recently cleared-out for my wife to park her "new" Lexus in), out of the open space where my vehicles live outside.


That space is dirty (sand, gravel, Oak tree leaves and debris blowing around) and open to invasive critters (we have mice, squirrels, 17? feral cats, free-range chickens from the neighbor's yard, and snakes and insects of all kinds); if I open up anything automotive outside to work on it, it's most likely to have something unwanted getting or crawling inside. The three garage bays (two are semi-permanently taken over by non-vehicular items) have much less likelihood for similar contamination, so I'm moving the X5 inside for a short-term exam.

I'm either rebuilding my home-made smoke tester (it needs greater output) or I'll buy a cheap one from Amazon or Ebay (not wanting to, having just spent about 2 grand on parts, repairs, tires, inspections, and registration renewals in a just over a month, from Sept.29-Oct.31), and try smoking out the mystery leak (my twelfth attempt, IIRC). This time, with no wind or bright outdoor light making the smoke disappear.

So, here's my question: when I remove all the obstructing covers over the rear of the engine, can I expect any difficulty upon reassembly, or possible breakage of 22+ year-old plastic pieces? I'll also be using an OTG/phone borescope, mirror, and stethoscope (I might hear an invisible leak?).

[X5chemist]

Check the three intake port covers. Depending on the year, the configuration is different. On mine, the large was cracked at several places. I'm surprised it didn't set any codes. I bought a small cap set and replaced them. The two small ones felt too loose. A zip tie was used to secure them tight.

[workingonit]

Originally Posted by X5chemist

Check the three intake port covers. Depending on the year, the configuration is different. On mine, the large was cracked at several places. I'm surprised it didn't set any codes. I bought a small cap set and replaced them. The two small ones felt too loose. A zip tie was used to secure them tight.

I compared your intake photo (after flipping it rightside up) and compared it to one on the E46 forum. I'm not sure which ports should or shouldn't be plugged on my 2001 3.0i, as I've never been able to see mine, yet. Why are all three plugged on your intake?

[wpoll]

Originally Posted by workingonit

... So, here's my question: when I remove all the obstructing covers over the rear of the engine, can I expect any difficulty upon reassembly, or possible breakage of 22+ year-old plastic pieces? ...

I doubt it - it all come apart and goes together very easily. The only exception might be the quarter-turn clips that hold down the scuttle section. These are a two-part deal, with a quarter-turn fastener fitting into a plug-in plastic "nut". I've had to replace a few of these nut - although not from breakage but from previous ham-fisted mechanics losing them while servicing the air filter (inc. the dealer!).



There's a few videos around showing how the filter housing comes out - like the one below. In this video, they remove some items I don't think are required to be removed (I never have) - the washer tank and battery cable. In fact, the way they remove the battery cable is downright dangerous! You also don't need to completely remove the rubber seals - I just pull them up and push them to one side.

https://youtu.be/JGYcwZSPFXw?si=Zq2anddoseTyRZJa

[workingonit]

Originally Posted by wpoll

...There's a few videos around showing how the filter housing comes out - like the one below. In this video, they remove some items I don't think are required to be removed (I never have) - the washer tank and battery cable. In fact, the way they remove the battery cable is downright dangerous! You also don't need to completly remove the rubber seals - I just pull them up and push the to one side.

https://youtu.be/JGYcwZSPFXw?si=Zq2anddoseTyRZJa

I found another video https://youtu.be/Eq00ZAOwc88 that shows what I need, though not featuring a 3.0i. Looks like no parts are subject to stress or breakage, so I think I may be OK doing this. I hate accidental breakage, especially when parts are rare.

[oldskewel]

Here are some pics of my 2001 3.0i, built in June 2001. Generally dealer-serviced by the PO. No problems in this area before or after. These pics were taken after I had removed and cleaned the intake manifold as part of a head gasket repair.

The second pic below is probably the clearest of the area in question. Two holes are plugged, and one is not - at one point I knew what that thing did, but you can probably look it up better than I can remember.

I can see (and guess / remember) that both plugs I made were done with what I had. One is a rubber plug with some electrical tape to make sure it stays in place - I remember the original plug was there, but the rubber was cracking and disintegrating so this was a huge upgrade . Similar on the other one. As said, no problems before or since.











Also, on removing things in the cowl area, I'll just say that all that plastic is extremely solid, easy to remove, and kind of amazing how much it opens things up when removed. So I would just start doing your work, but if you ever feel you'd get a better angle or access if something were moved, just take it out. Easy. I think the one extra helpful tool was a 19mm ratcheting wrench.

[workingonit]

Originally Posted by oldskewel

...The .. pic below is probably the clearest of the area in question. Two holes are plugged, and one is not - at one point I knew what that thing did, but you can probably look it up better than I can remember.

Attachment 83710....

Good photo to go by. Wonder why nobody epoxies the other two holes permanently closed, if they're not used?

By removing the plastic parts obstructing my view, I hope to see (with my fading vision) what or if anything is amiss back there. In the garage bay, with better lighting, a remote viewing tool, no wind (and with my electric fan off...how do I temporaily turn-off the aux fan, too?) I may be able to see a faint whiff of smoke previously unseen before.

Or I may just replace all aged vacuum hoses and caps straight away. I have a few feet of silicone tubing, and assorted rubber caps on hand, but I'll probably need to order parts as well. I won't know until I see for myself, first.

I got quotes of $150 and $160 for a smoke test at two local shops, so If I can't use my tester, or visually find a "mystery" leak, then I'm gonna need a smoke tester from Amazon or Ebay, or should I just start replacing everything I can reach?

[X5chemist]

Does yours have a secondary air injection pump? Emission changes are probably why the intake ports on mine are all plugged. With so much plastic, a smoke test may be worth it. Even a plastic solenoid can work and leak internally. I'll dig through removed parts. I say old O-rings can be a problem. A few connections came off way too easy. Some connections didn't

[workingonit]

Originally Posted by X5chemist

Does yours have a secondary air injection pump? Emission changes are probably why the intake ports on mine are all plugged. With so much plastic, a smoke test may be worth it. Even a plastic solenoid can work and leak internally. I'll dig through removed parts. I say old O-rings can be a problem. A few connections came off way too easy. Some connections didn't

Mine does have a SAP, but I've never tested it with my Foxwell, nor have ever heard it run (don't they all squeal or whine when running?).

I just tried to get my home-made smoke tester to work again, but it seems the heating element (a Performance Tool 120 Volt Soldering Iron) has burnt out, so I don't know if I want to try another element like it, though it worked OK for three test sessions, a year ago. My smoke tester is homemade, very low pressure, and probably not up to the job.


I've got 4 feet of silicone tubing 3.5mm id, and lotsa vacuum caps, and 35 feet of silicone tape to fix hose leaks, but until I've done a legitimate smoke test (that means that I'll need a lot of smoke, per Effduration in another thread of mine), then it's all guesswork. https://xoutpost.com/1218935-post23.html

[X5chemist]

The secondary air pump runs for a few seconds at cold start up. I'm not sure how or if it turns on with a hot engine. Have someone start it while you touch the pump. On mine, I don't think I heard it go over 45 seconds. When the pump starts to go bad, it will whine loud. You'll hear it sitting inside.