W124 e320 will not turn over, after new starter installed

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robbieesprit

Member
Joined
Mar 28, 2019
Messages
43
Location
maidstone
Car
e320 estate
So here is a bit of a conundrum:
I've been having some over heating issues, my last run out after changing thermostat, saw temp gauge at rock steady 82/3c. Result i think, engine now running at reasonable temp.
On Monday, went to start the car an all there was a clunk noice, rev counter blipped/ jumped...engine would not turn over.

Suspecting the starter (what a g*t of a job that is on your drive), I put a replacement in today, and for good measure installed a new battery, cleaned battery terminal (as old was past its best, and i need the car to be reliable)

went to start the car and ...clunk...nothing....(although slightly louder clunk with new battery)

Then i was consumed by that sinking feeling, all that work for nothing....totally gutted.

So any ideas? No alarm on this one....

First thought is that old starter was ok, and engine seized, but on last run out it was running cooler than before.....

why else would engine suddenly not crank? cheers in advance for your thoughts....
 
First check.
what does the battery voltage read when attempting to start?
 
stranger and stranger...

So got my wife out to help...

I showed her how to turn it over....clunk! / no start for me

Her turn.....it starts!!? I measure 13.9 volts at the battery when running, the engine runs smooth and sweet, ...tried 3 more times and started every time....even for me...When turning over its now much more stronger/ harsher and faster turn over...but not quite as refined as the old bosch starter removed today....

So where from here? the only thing i can think of is that when I removed the battery to put the new one in, I did notice that under the tray was some water....obviously, had some seriously heavy rain recently....could this be a factor? or ignition switch? or neutral safety switch?

is there a way to narrow down the fault....
 
Are you happy that all connections are tight? Battery earth connection to body, disturbed when removing battery?
 
Check that the bolts connecting the earth strap to the engine block are tight and there is no corrosion on the connectors.
 
You're not going to any faults while ever it is starting.
Start looking when it doesn't start.
 
Not sure what you mean by a "Clunk", is it a mechanical noise like the starter engaging but not turning or more like just a solenoid / relay picking? FWIW mine sometimes fails to start in park if it's been standing a while but will always start in neutral, either way there are relay type sounds, if it happens again try knocking it into neutral to see if its the switch on the gearbox.
 
Hi All, thanks for replies...

So I cleaned the battery connectors (wire wool) , and the leads to the starter when I swapped in the new one.
Havnt yet checked the other earths, but the lead from the battery to top of suspension mount/ inner wing looked ok (dry and secure).

One of the reasons I swapped out the starter was that turn over was that starting was getting a little laboured (but this could have been the battery too), the starter I removed (bosch unit) still had dust cap in the terminal, inside was merc part number, (so i was thinking possible original?). I ve had the car since 2013, so thought age of starter might be an issue...but Ive never had starting issue/ concerns before this was more out of the blue....

There is now plenty of power in the battery to turn the engine over.

I did notice that pelican part recommend replacing the gearbox earth strap, was there a historic problem with these? mine is pretty mucky, but looks sound, perhaps worth removing and giving a good clean regardless?

The clunk sound was really quite strong, like a loud click, almost as though the start would turn over but is being stopped.
I did try the, move the gear selector up and down trick, but this seemed to have no effect at the time, but im not ruling out the gearbox.
My hunch is the gear box neutral safety switch operating in park? Gearbox was second-hand replacement 4 years ago...so i dont really know the history....

So im thinking, remove earth straps, clean replace, replace neutral switch....
 

Rather than keep buying new parts that don't solve the problem and spending your time covered in grime try these guys, they are honest and reasonably priced. Both of our Mercedes go there.
 
Sounds good to go now just uses it ...New starter motor will have a new gear on the end and the car has an worn starter ring by now so both will have to marry in to get best results ..
 
Hi All,

Ok so start problem has occurred again (refuses to turn over). :rolleyes:
Common factors to last time it occurred are:
After longer use of an hour, motorway driving.
Loss of coolant leading to over heating. (but not registered on temp gauge 78 to 82 and my low coolant light is not working/)
An intermittent poor running/ lumpy rough noticed on idle at traffic lights...possible misfire/ engine management? (possible link to over heating?)

Luckily weather was poor, cold high winds and rain, which may have helped cool the engine.

I got the car started by, switching it on and off about 6 times (about the same number of times when I got it started last time), this led me to wonder if the computer would shut the car down if there was risk of damage? DId the on/off action reset the computer?

When it started I was back to silky smooth running, exactly what happened last time too...

(Ive just traced the coolant leak to a failed jubilee clip).
(As for poor running, im going to run down to local MB indie garage, Stevensons in Larkfield see what they say)

Does this ring any bells?
 

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