Mercedes-Benz Forum banner
1 - 6 of 6 Posts

· Registered
Proud owner of an Blue-Black (Charcol Gray) '91 420SEL
Joined
·
704 Posts
Discussion Starter · #1 ·
Hello fellow brothers and sisters of the D.B. World.
I have moved to another city and a different job and am not in control of the living area and parking area being in an apartment complex.
My situation: Wen out to the car to start it and go to work. It turned over about one full revolution and then I heard a clatter and a tooth being ground off of the starter or flex plate. The engine or starter locked up completely and when you turn the key there is nothing but the click of the starter relay.
Since I an not supposed to be working on the car in the parking lot where I live I did some midnight exploration very quietly.
I got the starter removed and did indeed find one tooth on the flex plate that is damaged. Since it was about r4 AM when I finished for the night I stopped there.
Back ground info. I put in a new OEM p/n timing chain and oil pump chain along with all new chain guides and sprockets about 25,000 miles ago or about two years ago. My heads were looked over by an engine shop and were o.k for continued usage.
This sudden stoppage of the engine could be anything from the starter going bad to something big inside the engine breaking or somewhere in between.
I am going to have the starter tested this morning.
I want to put a socket on the crankshaft bolt and turn the engine over by hand using a long breaker bar but do not remember what size socket that I need and since I am severely limited on the work that can be done I need to get in and out fast.
My question is that when this happens to other 4.2 engines what is the normal or average cause. I have not pulled the valve covers or anything else at this time and can not here where I am.
If the starter is bad which I think it is and the engine rotates over o.k. then I can hopefully get the new starter on and get it running well enough to get it to a a shop to get the flex plate replaced. The one tooth is damaged enough that it will not take long to become a dead spot and damage the new starter that has been ordered and going to.
Advice and assistance is solicited and welcome.
On a side note. I have been having idle issues that are progressively getting worse. At idle and up to around 1400 RPMs the engine usually runs rough. Above that range it is smooth so this seems to be fuel injection in my mind. Is there a place where I can send the whole fuel injection system too included the electronic portion and they can go through it and then when it comes back I can bolt it on and go without much work afterwords?
When my heads were off at the chain replacement I put in all new rubber boots and the big duct for the fuel injection system body. All new seals related to anything on the fuel system with the exception of actually going into the fuel system. I also change the fuel filter at the pumps and tank at this time. I did not replace the fuel injection nozzles and the spark plug wires and distributor cap were not replaced but the rotor was.
Thank you in advance.
Jim
 

· Moderator
1987 & 1991 C126
Joined
·
6,916 Posts
Hi Jim,

Were I in your shoes, I would first check the state of charge in the battery making sure 'its right up there'.. If not I would rectify this condition first.

Next I would put on the headlamps to see the current draw as the starter just clicks. IF the starter motor draws current the headlamps will dim considerably as the key is held briefly to START position.

This means either the engine is locked as you fear… or that is simply the starter has gone bad & will need replacement / refurbish...

If the headlamps DO NOT DIM then the starter will need replacement / refurbishment in my opinion.

Can't you gain access to some pulley or other to see if the engine is free?.. Just a few degrees of rotation (in direction of normal engine rotation) should allay fears of mechanical damage.. something seized I mean…

Good Luck man,

MBL
 

· Registered
Proud owner of an Blue-Black (Charcol Gray) '91 420SEL
Joined
·
704 Posts
Discussion Starter · #3 ·
Update on my issue.
My starter is indeed locked up and will not rotate by energizing it on a test machine. What is odd about this is that the ring gear does have a partial tooth ground and damaged. The bendix gear on the starter is in beautiful shape though. Things that make you go hummmmm.
:grin
I would still like to rotate the engine by hand if someone can tell me what the socket size that is required. I have to go and purchase one at a parts store as I do not have anything for 17mm with me here out of town.
Jim
 

· Premium Member
1991 560 SEC 1994 E500 2014 E350 Cab
Joined
·
7,040 Posts
  • Like
Reactions: mramay

· Registered
Too many to list
Joined
·
11,954 Posts
Why not Simply have it towed to a local shop who can rotate the crank and if it spins freely , change the starter ?
It's only abut an hours labor and you don't have to try to repair in a forbidden area
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top