E38 - Engine noise. ticking / tapping... continued....

[Chumpy]

Hi all

I put a post on a few days ago, regarding the ticking on the engine of my 740... I have copied the original post below, but I have an update...

After getting nowhere with my dealer, I decided to buy an oil additive for 'Hyraulic valve lifters'

I have put the additive in, and the engine sounds better, but still has the 'tick' when revving....

The car has only run for around 5 miles since putting the additive in.

Would anyone think that this may have been the problem??
Can anyone suggest if the noise when revving sounds like a lifter? or vanos... or anything else??

<a href="http://www.aspy.co.uk/e38740tick2.mp3">This is the noise now, after 5 miles on the additive
</a><br>

<a href="http://www.aspy.co.uk/e38740tick.mp3">This is the original noise...</a>



Thanks

Original Post......
Hi
My 2000 740 has a ticking / tapping on the engine.

At idle, the tick is around 4 times per second, and is definately linked to the number of revs.
You can listed to the tick at this page address Click to hear the sound!
I recorded this sound by pointing my microphone at the engine, with the bonnet up.
The car has 95,000 miles on the clock, and 'was' under BMW warranty when I took it to my local dealer 6 weeks ago. They advised me to carry on driving the car, as the noise did not have any affect on how the car ran. However, as the car was under warranty, I wanted it to be addressed, before something does go wrong which would cost me money.

The dealership are 'clueless' with regards to the problem, and have said that unless they can find a problem that warranty would cover, I would have to pay for full investigation, and probably for the repair. This seemed strange, as it was one of the reasons which I wanted a warranty in the first place!!

Anyhow, I have started to try to investigate the problem myself, even though I'm no mechanic.
I have borrowed a stethascope from a friend, and held it over the rocker covers of each side of the V8, expecting to be able to hear a loud tappet or valve lifter. There appears to be just an 'echo' of the tick in these areas. However, if I listen over the case ends (over the timing chain covers), the tick is very much louder. I'm not sure if this would be a genuine timing chain issue, or something else in this area of the engine.
I've had 3 740s and a 745. 2 of the 740's had mileage in excess of 95000, (one with 130,000), and both were lovely, with no engine noise.
My limited mechanical knowledge would be suprised if it were a chain issue, as I would expect a more constant 'dragging' sound, rather than a tick. (??)

Does anyone know how many chains are on this car?? My dealer tells me there are 3... (?) One for each side of the V, and one across the 2 sides.

Has anyone come across anything like this before?? Any ideas on what it may be, or what to check?? Any ideas on likely repair costs and 'seriousness' of the problem would help also.

Many thanks

[bmrtech]

Listening to your engine it doesn't sound like a lifter noise. It sounds like it is coming from the bottom end. have you checked your oil pressure? I had fixed a 540 with a similar noise with a new chain tensioner. Other cars had a failing oil pump or a broken chain guide. I would start with the cheapest repair which would be the chain tensioner. Good Luck! :)

[kwalther]

I have a 1997 740iL also. The engine is making the same type of ticking noise. I have about 66,000 on the M62 engine.
I'm hoping it might have something to do with spark plugs, or catalytic converters, or engine sludge. The engine makes a diesel-type sound when I accelerate and it sounds likes it’s coming from the passenger side. The engine is strong and fast, but the noise issue is obnoxious. Wonder what the problem could be?

[kwalther]

Since the last post I got out an ohmmeter and checked the continuity of the coils, then replaced the spark plugs with the Bosh OEM version.
Neither of these steps seems to solve the problem.
Again, the ticking noise seems to increase in frequency when the engine accelerates, which leads me to believe there is a mechanical misalignment or something.
The concept of a clogged hydraulic lifter, causing it to stay in a compressed position and hence creating a malfunctioning environment also seems logical.
I’m ready to start investigating the physical layer deeper, but before I go tearing into the engine block, I’m going to apply some engine detergent in an attempt to melt the alleged clog in the hydraulic lifter.
I’ve chose Amsoil Engine Flush to clean the slug. I'll leave it in my engine for 15 minutes at idol speed and then change my oil. Let's see what develops.

[TxDarth]

Since the last post I got out an ohmmeter and checked the continuity of the coils, then replaced the spark plugs with the Bosh OEM version.
Neither of these steps seems to solve the problem.
Again, the ticking noise seems to increase in frequency when the engine accelerates, which leads me to believe there is a mechanical misalignment or something.
The concept of a clogged hydraulic lifter, causing it to stay in a compressed position and hence creating a malfunctioning environment also seems logical.
I’m ready to start investigating the physical layer deeper, but before I go tearing into the engine block, I’m going to apply some engine detergent in an attempt to melt the alleged clog in the hydraulic lifter.
I’ve chose Amsoil Engine Flush to clean the slug. I'll leave it in my engine for 15 minutes at idol speed and then change my oil. Let's see what develops.



personally I don't care for flushes - they always seem to cause trouble.

I have seen 1 quart of kerosine added and run at idle for 10-15 minutes correct a sticking lifter in older GM cars. Then drain and refill as normal.