Gabriel S. wrote:
any 124 diesel owners have this...if you can call it a problem:
my car idles fine except i hear this CLICK CLICK CLICK CLICK....then i goes
away for a bit then CLICK CLICK CLICK CLICK
All Mercedes OM60x engines even those using approved conventional motor
oils, will eventually make this noise. Mercedes discovered it in the mid
'80s when they were being deluged with requests to replace "weak"/worn
lifters - and within weeks or months the noise returned. They discovered
that the returned warranty replaced lifters were NOT worn and almost all
of them met new specifications!
Replacing the conventional motor oil with synthetic will USUALLY reduce
and often eventually eliminate (but it may take 10s of thousands of
miles before it's completely gone) the noise. This has been the case on
all of MY cars - even when replacing the lifters didn't correct the
problem - and has on MOST of the cars that I've suggested it be tried on
- 90-95% of them. It will also reduce lifter noise on gasoline models,
but it's not nearly as effective (maybe 50-60%). Synthetic oils using
group IV & V base stock (Mobil, Amsoil, Red Line) work best. Synthetics
using group III base stocks (marketed as Rotella, Delo400, Valvoline,
Pennzoil, Castrol Syntec) don't work as well (in MY experience) but they
are superior to conventional oils (including the very best conventional
oils - like Delo 400 and Delvac 1300).
If the "O" rings on the stem of the oil filter cap become hard (they
petrify after 25-50kmi and need to be changed) hot idle oil pressure may
drop a little and lifter noise will become more evident. These "O" rings
(Mercedes part # 015 997 9448) really do need to be replaced every 5-10
oil changes! If the rubber grommet within the oil filter is displaced
when the stem is inserted into the filter, oil pressure will run lower
and lifter noise MAY become quite prominent.
Occasionally a lifter IS actually damaged and synthetic oil will NOT
completely eliminate the noise from a worn lifter. The 602/603 engine
manual shows how to test for lifter failure.
The serpentine belt tensioner shock absorber CAN make a noise that is
NOT unlike a noisy lifter (unless you've heard them both side by side),
but the lifter noise (at least at first) is usually much more
intermittent - once the belt tensioner shock bushing fails, there will
be a VERY insistent clack, clack, clack whenever the engine is running.
It will be modulated if you press hard on the upper or lower tensioner
shock bushing (depending on which one has failed)
Marshall
--
Marshall Booth (who doesn't respond to unsigned questions)
"der Dieseling Doktor" [EMAIL PROTECTED]
'87 300TD 181Kmi,'87 190D 2.5 199Kmi, '84 190D 2.2 227Kmi, '85 190D 2.0
159Kmi, '87 190D 2.5 turbo 234kmi
