Mercedes-Benz Forum banner

1 - 6 of 6 Posts

·
Registered
'89 300SE, '12 CL63, '17 AMG GTS
Joined
·
9 Posts
Discussion Starter #1
On Bring a Trailer, I've seen many sellers and commenters claim that early 1992 W140 cars did not have biodegradable engine wiring harnesses, and that the affected years were 1993-1995. I don't think anyone disputes 1993-1995 being affected. I've heard others say that all the LH-Jetronic cars had the biodegradable wiring harnesses, even including early MY 1992 made in calender year 1991. Some people on various forums and sites have claimed even 1996 and 1997 model years were affected, despite having the newer fuel injection system.

What is the correct answer? Were early MY1992 W140 cars affected by biodegradable harnesses? Were MY1996 W140 cars affected? MY1997?

There are many threads on this topic of course, but I've failed to find a definitive answer.
 

·
Registered
600SEL '93, SL600 '95, E55 '04
Joined
·
125 Posts
W140 had bad wires used for upper and lower engine harnesses from the start (1991) up to the end of LH in 95 however ETA wiring was good on early LH cars. That is 91,92 and some 93. In 94 MB added crapy wires to the game on throttle bodies and it went further to the HFM cars too but i dont know when that stopped.

Some 95 V8 R129s that were already on HFM also had problems with decomposing wiring on the engine but W140 was lucky not to get that crap.
 

·
Premium Member
'97 CL600
Joined
·
2,900 Posts
I have a '97 CL600 and thought I was "home free". WRONG! Yes, they replaced all of the wiring EXCEPT for six coaxial cables still used. One of mine went bad and we could find no replacement coax so I had to order a new harness. Had to go through The Classic Car Center in Irvine CA and got great service and pricing but a new cable with the 6 old wired coaxs. My hope is they are new and not 22 years old and will hold up for years to come.
Anziani
 

·
Registered
W463,W204,W210, W123, W140
Joined
·
570 Posts
I have a 1992 300se and the upper wiring harness was trashed and broke down. I found a replacement on Ebay from like 2004ish.
 

·
Registered
'89 300SE, '12 CL63, '17 AMG GTS
Joined
·
9 Posts
Discussion Starter #5
Thanks for your detailed replies folks. Now I understand it’s not a clean all or nothing affair, but rather different wires and harnesses switched to and away from biodegradable wiring at different times.

I’m buying a 1998 S500 sedan, so at least I should be in the clear there. I’m probably overpaying for it a bit (equivalent of $8k USD) but it’s hard to find clean well sorted W140s in Canada. I learnt with my W126, particularly if one doesn’t have the time, space, and skill do many repairs oneself, that it’s much cheaper to pay a premium for a sorted car than to pay a mechanic to sort out a rough one.
 

·
Registered
'98 S500, '99 S420 etc.
Joined
·
92 Posts
8 grand for a clean, sorted S500 today doesn’t sound bad to me. I would ignore most stories about cheap great Mercedes, just as I learned to ignore the ads for 50 dollar Jeeps, long ago.
 
1 - 6 of 6 Posts
Top