Noise in front of M50 engine

[yuki]

First of all, as this is my first post here, hi to everyone, please forgive that English is not my first language.

After spending a sizeable amount of time searching Internet about my car's problem somebody recommended this forum.

Car details: 520i E34, bought new and located in Spain December '94. I assume that it had spent a number on months unsold because it was heavily discounted (-23% from published prices) to fulfill sales quota for the year. If there is a sticker somewhere with exact options and manufacturing date please let me know. 136,000 Km, manual 5 speed, no modifications. Serviced all its life in the same dealer. Used only the syntetic oil recommended by manufacturer (it changed along the years, Mobil 1 at the beginning, later Castrol, Mobil again and now Castrol, changed around 2,000 Km ago). Steering pump was replaced 10,000Km ago along with all belts, water pump and tensioning pulleys.

The problem is that it had developed a rattling sound in the front of the engine, upper part. I have extensive experience maintaining all my bikes from 30 years ago and the noise reminds me timing chain slap, quite a plague in Honda bikes.

The dealer had demonstrated to be far from good when confronted with problems and I want to have a try at fixing it first.

I had read what I believe are most of the relevant posts for this kind of problem, both in this forum and usenet, and seems to be two possible causes, timing chain tensor or VANOS mechanism. Also were references to possible problems with oil pump gasket or oil pressure relief valve.

I had found also references to some kit to modify VANOS to 03 '95 specs but not detail of the parts involved.

The noise happens both with engine cold and hot, noisier when hot and diminishes when revved. Is not noisy enough to be heard in normal use but clear when maneouvering in confined spaces like the garage or with open hood.

My question is how to differenciate the possible causes of the noise and then how to fix it.

I have other problems with the clutch but perhaps they deserve a separate thread.

Thanks in advance.

[Blitzkrieg Bob]

got the same problem on my 94 touring.

Been trying narrow the cause too.

[BillionPa]

VANOS operates with high oil pressure, and it gets higher with RPMs.

i would think its the adjustment unit is failing.

11361748036 x 1
32411094908 x 1
07129900681 x 6
32411093596 x 2
11311722674 x 2
11361740840 x 1

thats the parts required to replace it.
there are other parts im sure need replacing when disassembling the engine.
have a diagnosis done before ripping it apart and putting in $400 worth of parts though, cause i could be wrong. :D

[Russell]

Might try different weight oil. Mine was very noisy, especially on cold start, with mobil 1 15w40 synthetic. I now use castrol syntec 5w40 and there is muych less cold start noise. Even so, I am not sure it would help in your situation..

[Blitzkrieg Bob]

Switched from M1 0-40 to syntech 5-50.

It got a bit quiter, but I can still hear those bouncing marbles.

I checked the old service records and the dealer had 5-50 in it and a Motor Oil Additive.

I wonder what that MOA was?

[Yiorgos]

Does your engine use hydraulic lifters?

Get some Lifter-free Wynns oil additive, or do an engine flush. The oil tunnels to deliver lubrication to the lifters aren't very wide and a carbon chip can easily block these tunnels, starving the lifters from proper lubrication.

If the lifters are the problem, I suggest the above fix ASAP, I left my lifters to chatter for a year without proper lubrication, and am now paying the price for replacement of all lifters + labour.

[yuki]

VANOS operates with high oil pressure, and it gets higher with RPMs.

i would think its the adjustment unit is failing.

11361748036 x 1
32411094908 x 1
07129900681 x 6
32411093596 x 2
11311722674 x 2
11361740840 x 1

thats the parts required to replace it.
there are other parts im sure need replacing when disassembling the engine.
have a diagnosis done before ripping it apart and putting in $400 worth of parts though, cause i could be wrong. :D

I had not found a decent diagram of VANOS but this parts list is for replacement of the actuator that seems not to rotate. I don't see it doing the kind of noise that I'm finding.

I just got hold of ETK and the parts replaced in 03/95 substitute a single washer for a sandwich of two flat washers plus a diaphragm spring in the intake cam sprocket. I think that this is the "BMA kit" mentioned in older posts
but don't know for sure nor about the feasibility of installing it without special tools or procedures.

It sounds more like slapping timing chain that anything else.

In ETK diagrams I cannot see any ratchet mechanism in timing chain´s tensor. Is it hidraulic? If this is the case then the piston can have excessive play or oil pressure is too low.
Is there a port somewhere to connect an oil pressure gauge?

[yuki]

Does your engine use hydraulic lifters?

Get some Lifter-free Wynns oil additive, or do an engine flush. The oil tunnels to deliver lubrication to the lifters aren't very wide and a carbon chip can easily block these tunnels, starving the lifters from proper lubrication.

If the lifters are the problem, I suggest the above fix ASAP, I left my lifters to chatter for a year without proper lubrication, and am now paying the price for replacement of all lifters + labour.

It does but the noise is from the front of the engine.

After cold start I can hear a ticking noise that could be valve chatter but it dissapears a few seconds as it should. According to BMW this is normal and not detrimental for the engine.

[Yiorgos]

It does but the noise is from the front of the engine.

After cold start I can hear a ticking noise that could be valve chatter but it dissapears a few seconds as it should. According to BMW this is normal and not detrimental for the engine.

That's fine, my chatter was at the front of the engine too, under the plastic cover. Do you mean the front of the actual engine, or the front of the engine area where the radiator and fan are?

The chattering is normal at cold and to quieten down (up to 5 minutes of running), however my chattering was still there even after 4 hours of driving, that's when I knew something was wrong.

[rob101]

That's fine, my chatter was at the front of the engine too, under the plastic cover. Do you mean the front of the actual engine, or the front of the engine area where the radiator and fan are?

The chattering is normal at cold and to quieten down (up to 5 minutes of running), however my chattering was still there even after 4 hours of driving, that's when I knew something was wrong.
did you consider that it could be your chain tensioners george? rather than the hyd lifters as you think (ie not such a big job to fix)

[Yiorgos]

Well I was stupid enough to leave my lifters without being lubricated for over a year, I'm pretty sure theyre stuffed. Do timing chain tensioners get checked over when doing a lifter replace? Not sure.

[rob101]

Well I was stupid enough to leave my lifters without being lubricated for over a year, I'm pretty sure theyre stuffed. Do timing chain tensioners get checked over when doing a lifter replace? Not sure.
wha?
you can't really leave your lifters unlubricated? was the car not run for a year?
i am confused.