'89 300E Distributor Cap/Rotor Lifespan?

All,
I have been troubleshooting my cars inablility to start after sitting for a week. I cleaned and check all sensors. I found that my Distibutor Cap had some condensation in it and all connections were
very green/corroded. Also, the pin that extrudes from the coil connection no longer protrudes to connect to the rotor, thus no spark.
I just replaced this 2 1/2 years ago, and norw it is completely worn out. I know I have placed about 40K or so miles on it, is that pretty much the life of it? I also noticed the plastic around the coil connection (on the inside of the cap) is partiall worn/burned away. I feel the seal failed, thus allowing the condensation to set in during a very warm/humid/rainy week of sitting.
So, I am replacing the Cap, Rotor and Seal. Should I expect that it is only good for 40K miles, or is the wear due to the condensation?
Thanks,
Thom '89 300E
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There's lots of rain in Germany so it's doubtful that the ignition suffered only from moisture. The clue to that is your comment about the coil's connector. There's no reason for it to be eroded, regardless of moisture, except if its connection to the coil wire were poor and sparked on that account.
I suggest you check the wiring schematic to ensure all is correctly installed AND that the ignition wires & coil wire are the correct ones for the motor.
Final thought: the distributor cap's wetness and the corrosion of its contacts suggests the motor may be running below 80 degrees C. - not hot enough to expel moisture.
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T.G. Lambach wrote:

I verified all connections and parts as part of my troubleshooting, they all match up. The car is alwaysrun at over 80c, it is my daily driver and It is driven 14 miles one way each time.
This car has had this problem for a while, only in very humid warm months. Maybe the quality parts I have ordered will be better than what I got locally.
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It is very important to use only original Bosch parts for the ignition. Other brands like Beru wont last nearly as long. 40K very good for a Beru set, 100K or more is normal for a Bosch. Some parts dealers try to sell other brands as original Bosch because the are listed in their pricelist as system Bosch. You should not worry to much about the seal, only ignitions designed to be submerged are completely sealed. And those ignitions often trap moisture inside. The damage to the cap is caused by the worn carbon pin..
Rob
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RobP wrote:

I thought the last one I put on there was a Bosch, but I see it wasn't. It came as a set, and not seperate like the parts I just ordered. I am still replacing the seal, the old one looks real crispy. I would figure it has a mojority of the 260K miles on it.
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    My '89 300E's cap and rotor have over 250k km on them (that's well over 150k miles for you) and are working as expected still
cheers
ps buy a dehumidifier.... hate to think what else might be corroding
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Guenter Scholz wrote:

Wouldn't do any good, no garage for the car. Actually, this has been my only issue with any type of corrosion in the engine compartment. I had this problem once before when my son drove it through high water a couple years ago (it then snowed 8 inches, so I couldn't get the car towed for a couple days, which toasted the dist cap)
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