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From digest.v7.n29 Thu Jul 31 17:15:55 1997
From: (C Bowe)
Date: Tue, 29 Jul 1997 23:31:51, -0500
Subject: 540i short block question

<Looks like my new car research was not so good after all. About 3 <days after finalizing the deal for my '95 540i I get the news about <cylinder wall corrosion related to sulfur-laden fuel. Can someone <provide a lot of detail on this <snip>>>>>>> <

Jack et al:

I have the same issue with my ‘94 540ia and have learned quite a bit about the problem on the digest and elsewhere. Punch line for me is that my baby goes in for a new short block next week. I was planning on summarizing the whole experience on the digest a couple of weeks after the work but in response to your query and for the benefit of others I’ll summarize what I’ve found so far:

The problem is in the lining of the cylinder walls of the 93-95 (or later?) 5 series V-8s. One is called Alusil, the other Nikasil. I forget which one is the “good” one. The sulfur causes what amounts to etching in the walls allowing some compression loss. Manifests itself as a rough idle at first, which gets rougher, presumably leading to poor driveability & loss of power. I don’t know what the long term result would be and I don’t want to find out.

The dealer will have a protocol of tests to run, starting with checking vacuum connections but leading to the important one, referred to as the “idle quality test.” The outcome of these tests provides the proof to BMW that a new short block is needed, and takes a half day to run.

The rough idle can be detected best, well, at idle... In D, let up lightly on the brakes and you may notice the car lurching unevenly forward, or even shaking up and down a bit.

One service guy told me that the problem is most common on urban cars (esp. areas where reformulated “winter gas” is mandated) and also more common on the earlier cars (my DIS was 11/93). My dealer, Heishmans (near D.C.) says they’ve seen only 3 or 4 of these that needed the short block replacement. Guess I’m # 5. They said they’ve done one w/86K mi. and others with lower mileage like mine. Another dealer told me it was common for dealers to do the short block on these when they come off lease, as the warranty hours allowed for the job are generous. I don’t know how true that is, but you might want to search your car’s service records to see if it hasn’t already been done.

My tests showed loss of compression in 2 of 8 cylinders that was “significant,: with beginnings in a third. They will replace the whole short block, will add new plugs and replace whatever else is not working (e.g. leaky water pump?) or worn (under warranty). I still need to inquire what they do about the timing belt (or is it chain? shows how much I know!). They allowed 2 weeks for the block to come in.

My car is still under the full warranty (only 26 K miles) but the engine has an extended warranty out to 6 years/100K mi. because of this problem. If you request it from BMW I think they will send you proof of the extended engine warranty on your car. Some people I know have suggested that I put it off until the motor has many more miles on it and then get a new motor but I prefer just to get everything back to perfect and be done with it.

They say the job takes 3-4 days and have arranged a rental car for me courtesy of BMW. Once the work is done I will post a follow-up article with the out come (likely in 3 weeks) along with any other info that I’ve left out or discover along the way.

Chris Bowe
94 540ia
95 Isuzu Trooper (yea I know - whoops!) 94 Volvo 855 TW (yea I know again )
BMWCCA # pending

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