2007 N52 Coupe, what sort of mileage should you replace DISA vales?
- Thread starter Ilogik
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Very easy to take out the big DISA, inspect and clean if necessary. Do this before you decide to replace. Not so sure about the small DISA which I’ve only had out with the manifold off. I imagine it’s quite difficult to get at (although taking the manifold off isn’t all that difficult).
Can be a bit of a lottery from what I've read. I checked mine because I got a code for the big one and it was destroyed when I pulled it. Personally I am taking the view that if the big one is wrecked, the small one probably isn't doing so well either so I got replacements for both. As Zebedee said, the big one is easy to get at so start there.
Re brands, I ended up getting a pair of good condition 2nd hand BMW original units on ebay to sort it in the short-medium term. I believe the OE is Mahle but I don't think you can get those new now. I've seen people tout Febi, Vaico, and Rein as decent aftermarket alternatives but all of them seem to have somewhat mixed reviews. Originals from BMW will be the "safe" choice mechanically, but not for your wallet.
Re brands, I ended up getting a pair of good condition 2nd hand BMW original units on ebay to sort it in the short-medium term. I believe the OE is Mahle but I don't think you can get those new now. I've seen people tout Febi, Vaico, and Rein as decent aftermarket alternatives but all of them seem to have somewhat mixed reviews. Originals from BMW will be the "safe" choice mechanically, but not for your wallet.
Finland
While you are inspecting DISA valves, look carefully for oil contamination in the manifold and on the DISA valve(s). With time and mileage the CCV (PCV) systems age out. If they allow exces oil into the manifold, the DISA's can (will) be compromised.
At 105K miles I replaced both DISA valves and my entire CCV system. My 2006 coupe has the Silver Top N52 with separate CCV under the intake manifold. When I took the manifold off to replace the CCV components, I discovered that there was considerable oil in the manifold and on the DISA valves. With all components removed, I laboriously washed the oil out of the manifold. I deemed the small DISA seals perished, but I saved the larger DISA as a possible spare. I bought Rein brand DISA's at about 50% of best OE BMW discounted price I could find. They've been fine for about 4K miles. I'll report if they give trouble.
At 105K miles I replaced both DISA valves and my entire CCV system. My 2006 coupe has the Silver Top N52 with separate CCV under the intake manifold. When I took the manifold off to replace the CCV components, I discovered that there was considerable oil in the manifold and on the DISA valves. With all components removed, I laboriously washed the oil out of the manifold. I deemed the small DISA seals perished, but I saved the larger DISA as a possible spare. I bought Rein brand DISA's at about 50% of best OE BMW discounted price I could find. They've been fine for about 4K miles. I'll report if they give trouble.
Honestly, I think there is no set interval. On my 2006 3.0si, 68K miles the "easy to get to DISA" was fine but the inner DISA had its rubber erroded and caused loss of power and idle issues. The green rubber was smeared (melted) across the intake runners and I even found small bits of it in the MAP sensor, which I only discovered when I pulled the intake and associated parts.
Running DISA tests via INPA didn't show anything because the flapper valves still actuated just fine, but due to loss of rubber, it wasn't sealing correctly.
My CCV+ breather hoses were also totally shot at that point so the combination of bad CCV and DISA caused noticable loss of power. I suggest bitting the bullet and pulling the intake and just replacing the parts (DISA, CCV, hoses) if you're beyond 60K miles and it hasn't been done before. I also suggest OEM parts, if you're doing the work yourself then buy the BMW OE parts knowing you won't have to do the job again for a long time.
One thing I didn't see in any of the guides on doing DISA, is when you pull the intake, the brake booster hose has to be removed to pulled the intake, so it's a good time to replace that hose and the clamps as well.
I also replace my starter + crankshaft sensor when I pulled the intake, I had a lot of "long cranks with no start" conditions, with the intake off, the starter really takes 10-15 mins, new starter fixed the long crank problem ; the sensor is one of those "while you're there", you can get the OE VDO sensor instead of BMW. The hardest part about replacing the starter is torquing the long bolt by 90-deg, which I accomplished by putting a mark on the bolt and using a mirror to verify 90-deg of rotation (the bolt threads from the "back" side so visibility is tough.
Running DISA tests via INPA didn't show anything because the flapper valves still actuated just fine, but due to loss of rubber, it wasn't sealing correctly.
My CCV+ breather hoses were also totally shot at that point so the combination of bad CCV and DISA caused noticable loss of power. I suggest bitting the bullet and pulling the intake and just replacing the parts (DISA, CCV, hoses) if you're beyond 60K miles and it hasn't been done before. I also suggest OEM parts, if you're doing the work yourself then buy the BMW OE parts knowing you won't have to do the job again for a long time.
One thing I didn't see in any of the guides on doing DISA, is when you pull the intake, the brake booster hose has to be removed to pulled the intake, so it's a good time to replace that hose and the clamps as well.
I also replace my starter + crankshaft sensor when I pulled the intake, I had a lot of "long cranks with no start" conditions, with the intake off, the starter really takes 10-15 mins, new starter fixed the long crank problem ; the sensor is one of those "while you're there", you can get the OE VDO sensor instead of BMW. The hardest part about replacing the starter is torquing the long bolt by 90-deg, which I accomplished by putting a mark on the bolt and using a mirror to verify 90-deg of rotation (the bolt threads from the "back" side so visibility is tough.