I live in NJ and the weather has been cold more recently and more so than last winter. This is my 2nd second with the car. Its a 78' 300D. The other week it had a weak start and I needed my jump box to get it started. It ran fine for another week and now I don't get anything (no click). I currently can't get my hood open (another problem), but I read the cold is bad on the diesels. Starter problem, alternator? I changed the battery last year. any thoughts... once I can get my hood open?

 

Well I walked over to my car yesterday and the car started without any problems. So I guess the Mercedes thought it was too cold to run before. I also was able to open the hood on the car. Damn those winter gremlins.

 

I had a similar problem. i was able to shift thru the gears and just wiggle the transmission ground enough to start her. i would take her to your local national chain auto parts store and have the battery and alternator tested while still installed. if they test faulty pull the alternator and have them bench test it. do the same with the battery. you can pull an alternator in 10 min if you have done it enough. just remove the bolts slide it forward as close to the radiator as possible and slip her out up in between the fan blades I don't have the A/C compressor installed so it might go differently for you.

it could be the neutral sensing switch but if it still does not want to start in Park or Neutral keep reading

if every thing so far checks out ok i would suspect the grounds. get out the cordless drill and the wire brush attachment and clean the connections. look for broken or failing ground straps.

grounds are usually the case if you have intermittent electrical problems.

finally i would suspect the ignition

if you get no click you could check to see if the solenoid on the starter is getting power. just pull out the voltmeter in your glove box ( i know you have one there don't you?) and have a helper try the ignition.

get back to us, but my paypal dollar is on the grounds.

if the alternator does bench test bad you don't need a new alternator. just a new regulator/brush combo, unless the bearings are bad. an alternator can go thru 2-3 regulators before the commutators are worn out. $15 instead of $110 sounds like a deal to me.

 

Do you use an engine block heater? - Hear tell it extends the life of a diesel engine by 30 % and it is a must for cold days.

 

Car continues to start with no problems after that flukey day(s). I will start using the block heater, but a closer look at the electrical plug and wires and they are pretty frayed. I need a warm day to get out there and fix that up. Thanks for the advice on that I will make it my routine to use it. I have heard 2 things... keep the heater on all night or use a XMAS tree timer and keep it on a few hours before you use it. Any thoughts??

 

it depends on what type of heating device you use. a block (coolant) heater should be fine to plug in all night. many are thermostatically controlled as well. if you go for an oil pan heater most that i have seen are not thermostatically controlled and are sized to the capacity of your oil pan. in that case i would use the manufactures specs and determine how long you need.

in short:
thermostatically controlled oil pan or block heater don't worry about it.

non thermostatically controlled oil pan heater check with the manufacture.