Mercedes-Benz 420E

1994 Mercedes-Benz 420E Engine Failing Happens always When warm 

Vehicle has all MB maintenance. 60K Miles. After
approximately ten to fifteen minutes of running time. Does not matter if idle or driving. Engine quits. After 30 to 40 minutes car starts. Same
scenario repeats. Replaced thermostat, did nothing,
Dlr said so. Now Dlr says neeed new dist caps,seals.
rotors both sides, big bucks. P.S. New battery,
electrical no problem. Feels like no iginition
turns strong on starter.I live in Anchorage Alaska,car starets right up @ -10F. What gives?
Tks Capt Krissy

Sounds like they are guessing on your wallet. This is no good. I recommend finding another repair shop. Seek a quality import shop that will actually perform diagnostics. Most of the time when you experience this type of stall it's because a component fails when it's hot. Once it cools it works again.

How much did they quote you for replacement of the parts?

BTW, what does Tks mean?

TKS means thank you for short. They estimate under
a thousand bucks for parts and labor with MB parts.
I knew it was probably a warm part that is failing, but wanted a more specific or re occuring item that you may know from this type of equipment. I was
wanting to hear that the dist cap and rotor deal was
a joke. It would start hard and run the same way.
The heat could not increase the resistance in the
ignition that much could it?
Just started the car at -5 F after two hours cool
down time. Started on first rotation.

Thank you,
capt krissy

CK- 'I was
wanting to hear that the dist cap and rotor deal was
a joke.'
R- I was close to saying that and normally would. Except it is known to cause stalls on these cars.

CK- ',but wanted a more specific or re occuring item that you may know from this type of equipment.'
R- I did a TSB (technical service bulletin) search and nothing came up.

CK- 'The heat could not increase the resistance in the
ignition that much could it?'
R- I would consider it unusual. And I'm guessing the problem is not the parts they want to replace. Unfortunately that is all I can do from here.

CK- They estimate under
a thousand bucks for parts and labor with MB parts.
R- Don't they make enough money selling cars (almost have to wonder if that is there intention)? That is to much. Did they have a good explanation for wanting to replace these parts? Did they inspect these parts and find problems (or do you think you could)? Did they scan the computer for fault codes??
Did you know you can buy MB parts from non dealers? On the internet I found the parts for $200-300 (and these were Original Equipment, non OE actually cost more). But I wouldn't spend that much until I knew the parts were bad.

With the temperaturs your dealing with I wouldn't be surprised if you were in Miami the car wouldn't run at all.
Would you believe it's colder here in ny (near fort drum) than anchorage. Yesterday the daytime high was minus ten with nighttime windchills around min 50.

Email me if you wish and we'll discuss possible alternatives,
[redacted]

I have the car in the garage warming up and will try
to check the dist cap and rotor and see if it looks like corrosion (piting or whatever)and go from their.
Will get back to you
Tks Capt Krissy

The site was down for a while, at least on my end.
If you do find corrosion thoroughly clean it.
If you email me I'll send you some information that may be helpful.

Hello?

I haven't heard from you. Curious what you found.

Took about ten minutes to access each dist cap and rotor assy. Badly pitted and corrosion rampant. Same amount on both sides. Have a "fine" set of ignition files and cleaned both cap and rotor contacts. Cleaned contact with cleaner spray and reassy. Started vehicle and let it run at idle for forty minutes before shutting off. Slight hesitation on initial accelerator application but appears to run much better. Will try today for run at highway speeds. Still don't trust it yet. Still -15 below and don't want to get stuck. You might be right. Now the big question. These contacts were bad. Did my scratching, gouging, etc. change the tolerance enough between these points of contact to change the performance of this part. Stupid question?
Tks Krissy.

-15F, ouch if you get stranded. Is AAA motor service available in AK? I recommend the AAA Gold (or whatever the premium service is), if you break down they will tow you up to 150 miles to a destination of your choice (probably home for you). This is Vs the standard service in which they tow you to the nearest shop.

On the tolerance, my guess is no better than yours. But it sounds probable.
Were you surprised at the amount of corrosion?
If you are interested in performing your own maintenance,diagnostics, and repairs there is site dedicated to the DIYer. It does cost 24.95 per year. This site is also available to shops, it's the information system many independent professionals use. In other words it blows away a $15 manual. And at the same time remains well under the cost of MB cd's.
Interested?
BTW, I have no vested interest in the above... :)

Keep in touch and good luck

Capt Krissy,

Haven't heard from you.. Did you resolve your problem??

Douglas: Sorry it took so long. I have replaced the
rotors, caps, and dust covers. It was the problem. Note there is a change in the new part. The rotor caps is stronger and has a much better insulator (actually a different part number) due to
the change. Appears that it was grounding out thru
this weak area when getting hot. Thank you. I will release the funds to you.
Capt Krissy