DISA Valve Replace or Rebuild? What's the consensus? ANSWERS

[StudioWizard]

So, here's what I'm gathering from talking to mechanics, parts companies (GAS and X8R) and you guys: it's probably pretty rare that these cause catastrophic engine damage, but the design of the OEM unit is poor. Upgrading the OEM unit is inexpensive (relatively) and makes sense to do just to have one less part breaking down the road AND it might, in rare situations, prevent major engine damage.

The guy at FCP Euro emailed me that the Vaicos and other aftermarket parts are definitely inferior and are really mean to be a stopgap measure rather than a long-term fix. I immediately canceled the order and he was happy to do so even though he already shipped it out. He emailed me a free return shipping label already. I should have asked BEFORE I bought it. The good news is that they are totally honest and also the folks at GAS and LNPR (X8R) said the same basic thing.

So, there you have it. It seems like we do have somewhat of a consensus - at least one that I'm satisfied with.

[Special Kay]

Mine was loose as a tarts drawers Studio....why take the chance...?

Tarts don't wear drawers

Proof Kay.....Chris D modelling them....

O dear O dear, I'm having scary thoughts of attending any Z4 meets

[enuff_zed]

Just read through this thread and all I would add is that if your disa works ok then don’t buy another to upgrade. Takes five minutes to remove yours and about ten minutes to fit the new parts.
Do be aware that the flap section on the 3.0 is longer than that of the 2.2 and 2.5, so get the right kit.

[StudioWizard]

I think that's the right call. Right now my car is in the shop getting a laundry list of fixes done. When I get it back, I'll take a look a the unit. If it's OEM and in OK condition, I'll upgrade it.

[john-e89]

Just read through this thread and all I would add is that if your disa works ok then don’t buy another to upgrade. Takes five minutes to remove yours and about ten minutes to fit the new parts.
Do be aware that the flap section on the 3.0 is longer than that of the 2.2 and 2.5, so get the right kit.

Good point which I didn't mention Enuff.

[Mike6]

I believe it is virtually impossible for the pin to drop into the inlet whilst car is in operation. It simply cannot move back enough in its housing to drop out. However as I understand it the pin can drop out if you are not careful whilst removing the DISA for inspection or whilst putting it back in after inspection and its is then that the engine can be destroyed.

[StudioWizard]

So maybe the article I read was scare tactic or something.... Here's a link to the article:

https://bmwtuning.co/m54-engine-problems/

I'm curious what you all think.

[StudioWizard]

I also just emailed the writers of the article to ask if they have any first account experience of a DISA unit failing and causing major engine damage from a dislodged pin or other debris from the unit. I'll keep you posted.

[Chris_D]

So maybe the article I read was scare tactic or something.... Here's a link to the article:

https://bmwtuning.co/m54-engine-problems/

I'm curious what you all think.

That's actually a good, well-written, accurate and truthful article.
Most M54 engine owners, including myself have experienced most of, if not all of those issues.

Where they indicate that 'debris can get into the engine, and that's not good', well, of course that's a plausible claim, but it's still anecdotal and doesn't offer any evidence. So I wouldn't regard it as scare tactics necessarily. It may have been better to elaborate on the risk of damage occurring should the DISA fail as it can fail in more ways than one. It can also fail without damaging the engine of course.

[StudioWizard]

Agreed.

I read the article, then started researching on Google/YouTube (uh. oh.). And of course, I found videos that talked about how a filed DISA unit can "grenade" your engine. Here's the one I watched:

https://www.youtube.com/watch?v=ZNYUhWk6WUc

He seems reasonable... but the fact is that his engine did not suffer catastrophic engine damage.

[StudioWizard]

Here's one of the comments from that video:

"@TheDemockery
8 years ago
If the DISA valve fully fails, parts of it will get sucked into the engine, which may cause significant damage. At the least, the head will have to be removed to repair the engine. I know this from first hand experience."

So there's some "firsthand" experience via YouTube comments for whatever that's worth.... maybe not much. haha I found lots of other articles and comments where people claimed their engine was badly damaged due to DISA failure. Somebody on Amazon posted a review for a cheap aftermarket DISA unit that failed soon after installation and said that this cheap unit caused him $4000 worth of engine damage.

[enuff_zed]

The pin can’t fall out, but it can rattle until it shears. Then the whole thing can potentially fall apart. I have had one where the pin was worn to less than half its original thickness so I guess eventually it would wear right through.

[NaweedMustafa]

I immediately canceled the order

Good choice. The aftermarket ones are no better. the OEM is very expensive. I ended up rebuilding my original 20 year old DISA and all is well. Better fuel economy and no more hesitation at lower RPM's.

Posted what it looks like after 260,000+ KM's > viewtopic.php?t=141384

My advice is, if your current DISA's diaphram is good, just rebuild it with the aluminium kit. you can test the diaphram by setting the car key to pos2, then block the vacuum hole tightly with your finger, then unplug the disa power connector. If the bell crank arm, moves slightly, then youre good. once you remove your finger, the arm should move all the way back to its homing position. Bear in mind, a working bell crank arm does not mean your flap works. if you look at my thread, for the past year i believed my DISA was good when in reality, the flap was just spinning freely.

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disa2.jpg (82.54 KiB) Viewed 465 times

[Tango22]

Hi all, as far as I'm aware the DISA on the N52 engine can't be rebuilt using the X8R kits, so what options for replacement DISA's do us facelift owners have?

I don't want to buy an aftermarket version which is going to be problematic- is OEM BMW the only thing available in that case?

[StudioWizard]

Did you contact the guys over at X8R? They're very responsive. They'll probably know.