300D starter problem
 

My 1985 300D has intermittent starting problems on hot days when the engine is warm. Occassionaly the starter will not crank when the ignition switch is in the start position, there is an audible click sometines but no electrical indication in the dash instruments that there is any electrical draw".
If I lift the hood and let the car set for 30 to 60 minutes then the starter will work normally. This problem has never occured on a cold start. I am thinking that perhaps the starter needs rebuilding due to age (20 years) or miles (140,000). I suppose that just the solenoid may need replacing. Can anyone provide a diagnosis on which parts should be replaced? Also this car originally came from California and due to California requirements has some unique equipment on it for a 300D, it now resides in Upstate NY.

Regards

Pilot

Hi pilot , sounds like a resistance problem . It gets worse when it's hot because the higher heat increases resistance even further causing no start until it cools down. Check the battery connections and the starter and ground connections.If all the big wire connections are good then test the battery, replace the starter if the battery is good. Good luck

I've been there more than once with 123 starters. Replacing the solenoid will cure it.

One hint, but I'm not sure you can get to it on a turbo to do this. On my 240D's and my daughters normally aspirated 300D, I was able to use the lug wrench to jump between the starter post and the battery connection that is on the solenoid. This would spin the starter a little and it would then start.

I did this as an emergency procedure more than once to get back on the road again. You can't drive these cars 800,000 miles without getting in that situation from time to time.

If you decide to replace the starter, DON'T just go to the local auto parts and get one. Most of the rebuilts are junk, some of the Bosch rebuilts are even junk. I would either get one at the dealer or call Steve Brotherton at Continental Imports and get one from him. He is a known good Bosch authorized rebuilder.

This is much more important on a 300D than on a 240D because it is a MUCH more challenging task to change a starter on a 300D than a 240D.

Good luck,

very frustrating problem that I ran into several years ago where car wouldn't start when hot. Replacing the starter will do it. I got a nice BOSCH replacement one - one car's from mercedesshop or impco and the other from the dealer i think - but get it from a reliable source. I put a cheap ass replacement rebuild first and had to take it out and put a good replacement one in again.

This sucker is heavy on my car and a PIA to change. The top bolt was so tight that I actually had to have the dealer loosen the bolt slightly. (They were nice enough to do it for free after buying the starter from them).

No problems since, but i spent countless hours trying to figure it out. Only happened on the hottest of days and it left me stranded in a parking lot a few times (since it never happened while cold start at home).

A temporary soultion I found was to "hotwire" the starter to turn over form the wiring block at the front right of the car. I don't remember the exact contact points, but it would usually start from there if it went click-click from the keyswitch (probably less resistance). Be careful though. Looks like larry bible also has used this (read it just now) method.

Good luck. I've had no problems since proper replacement. Both cars eventually developed the same problem so it's a common point of failure it seems. (To be Expected i guess after 20+ yrs of starting!)

starter 300D
 

Where can I contact Continental Imports (Steve Brotherton)? The reply from Larry Bible mentioned the solenoid as the likely problem, Is the solenoid mounted on top of the starter so that it requires starter removal? I am inclined to replace just the solenoid if the probability is high of solving this not start problem. We are having very high temperatures is Upstate NY (95), if I lift the hood when I park the car on pavement it starts, if I park the car with the hood closed and on hot pavement then it will not complete the starter circuit until the engine cools down. These symptons lead me to wonder if the starter is getting tired and not just a solenoid problem. I would like the problem to be just the solenoid as the fix would be much more economical. Can you reassure me that it is probobly the solenoid?

Pilot

numerous airplanes
Bristol Bus
260Z, JD tractors. etc.

I have replaced the solenoid without removing the starter on a 240D, but on a turbo five cylinder I would be surprised if you could do it. Given the difficulty of replacing the starter on a 300D, however, it's worth a try.

Do a google search for Continental Imports, Gainesville, FL.

Good luck,

I am having this exact same problem with my 1983 300D. Starts fine when its cold or when the car has sat for a couple of hours. But on numerouse occasions on hot days I will shut down the car and try to start it a few minutes later. I can hear a click but the starter doesn't turn over. I have replaced the started because of this 4 times in the past 18 months. I just replaced the starter 3 weeks ago and it did it again. Each time these have been Bosch rebuilt starters.

However this time I was on my way to a very important meeting that I couldn't miss. I stopped by a store for a few minutes to get something and when I came out it wouldn't start. The temp gauge was showing around 100 and I didn't have time to wait for it to cool down. So I filled a couple of bottles up with water (I know this isn't a good idea) and lightly poured water over the engine to cool it down. The engine cooled down to below 80 in about 5 minutes and it started right up.

What could be causing this?

Starter
 

1984 300d Turbo
Replace The Starter, Soleniod Is Sticking When Engine Hot, Lower
Transmission 4 In Take Trans Mount 4 Bolts Out, The Center Drive
Shaft 2 Bolts, Support The Trans, Use 2 Ft Or More Ext 3/8 To 10 Mm For Top Bolt And Turn With 2 Ft Breaker Bar, Turn Fr Wheels To
Right Diy 2 Hrs

I have replaced the starter 4 times in the past 18 months. I just replaced it 3 weeks ago. There has to be something else going on here.

the poster who suggested checking
 

your grounds was right on.

it may need a starter or a solinoid for sure but it also could be a ground problem. and checking grounds is pretty easy and basically free. also examine the positive cables.

i have had them break 90% before (not on a benz but it could happen).

after doing this if it still is acting up then go the replacement route. i would also get a check done with the instruments at autozone or someplace like that. they can check to see what the draw is when starter is operating and if too much indicates bad starter. they may be able to verify ground too.

tom w

The bad starter is a rebuilding problem. There are 2 levels of Bosch rebuilt starters and alternators. As Larry Bible mentioned above the ones you buy at the 'Mcparts' store or the one you get from a dealer or Euro Indy like Steve at Continental Imports or here with Phil. In this case you get what pay for , BTDT .

Well I guess its time to replace the starter again. I drove the 300d to work today and left if there till I got out of work 9 hours later. We had a unusually warm day today however. We had a high of 84 degrees......pretty wild for the end of Febuary, anyways the car set there for 9 hours so I would figure it would have been cool enough to start but unfortunately no. So I have decided to take this fifth defective starter back to O'Reilly's auto parts and just get my money back. So I am looking to buy a decent starter......who sells decent starters? Links would be appreciated.

Thanks

I assume people will suggest to get my starter from Steve at Continental Imports or here with Phil. What kind of warranty do they offer on a starter?

I would assume 1 year but just ask Phil.:)

starters
 

Listen to all the other replie's to your post, but don't forget Tom's post about bad grounds: at battery; battery to block; starter housing to chassis; chassis to block. They all need to be good anyway, so I agree with Tom to do this first. It's just strange you're going through starters so quickly, even if they're cheap rebuilds. Regardless, redo all the grounds and all the connections to starter.