Used C300 is a complete nightmare... please help
Thread Starter
Junior Member
Joined: Dec 2021
Posts: 26
Likes: 0
2010 C 300
Used C300 is a complete nightmare... please help
Sorry for the dramatic title, but I bought a used C300 last year (115k miles) and it has been nothing but trouble ever since.
Had to replace drive belt + idler pulley within two months of purchase. Three months later, the engine died while idling at a red light. After that, the car sat unused under a tree for a few months, so a bunch of leaves piled up and blocked the sunroof drain, thus causing rain water to build up under the floorboards and short out the wiring to the starter.
Took it to MB dealership and they charged $3500 to drain the water, and then wanted $11,000 to replace the engine. I fought them on this for months, finally got a refund for the $3500, and took the car to an indie mechanic who replaced the entire engine (plus the starter and a few other pulleys, filters, and fluids).
Now, just a month later, I'm having an issue where it takes several tries to start the car. I sometimes have to turn the key multiple times and it will occasionally take several minutes before it will actually turn over. I'm really dreading this being the EIS/ESL failure, but I'm not getting the "take key from ignition" message, and I'm definitely still hearing the typical whirring sound when the key is inserted and turned all the way.
It doesn't happen every time, either — mostly when I've been driving for an extended length (i.e. 1hr or more), turn the car off, go inside somewhere, and then try to restart.
Any ideas about what else it might be? Thanks so much everyone
Had to replace drive belt + idler pulley within two months of purchase. Three months later, the engine died while idling at a red light. After that, the car sat unused under a tree for a few months, so a bunch of leaves piled up and blocked the sunroof drain, thus causing rain water to build up under the floorboards and short out the wiring to the starter.
Took it to MB dealership and they charged $3500 to drain the water, and then wanted $11,000 to replace the engine. I fought them on this for months, finally got a refund for the $3500, and took the car to an indie mechanic who replaced the entire engine (plus the starter and a few other pulleys, filters, and fluids).
Now, just a month later, I'm having an issue where it takes several tries to start the car. I sometimes have to turn the key multiple times and it will occasionally take several minutes before it will actually turn over. I'm really dreading this being the EIS/ESL failure, but I'm not getting the "take key from ignition" message, and I'm definitely still hearing the typical whirring sound when the key is inserted and turned all the way.
It doesn't happen every time, either — mostly when I've been driving for an extended length (i.e. 1hr or more), turn the car off, go inside somewhere, and then try to restart.
Any ideas about what else it might be? Thanks so much everyone
Thread Starter
Junior Member
Joined: Dec 2021
Posts: 26
Likes: 0
2010 C 300
Some more info:
I've tried both key fobs and had the same issue.
Checked the instrument cluster menu. While idling, the battery is at 13.5V — driving, it gets up to 14.7 or so, but seems to stabilize around 13.5.
The IB value, however, hovers around 1 to 3 A while idling. I could be wrong, but that seems low. Possible issue with the alternator/voltage regulator?
I've tried both key fobs and had the same issue.
Checked the instrument cluster menu. While idling, the battery is at 13.5V — driving, it gets up to 14.7 or so, but seems to stabilize around 13.5.
The IB value, however, hovers around 1 to 3 A while idling. I could be wrong, but that seems low. Possible issue with the alternator/voltage regulator?
Last edited by Ben_prima; Aug 30, 2022 at 05:40 PM.
Super Member
Joined: Apr 2008
Posts: 764
Likes: 171
From: Walnut Creek, CA
325Ci, 325Cic, C300
Man that's rough. Nothing to contribute other than I hope you get those issues sorted and begin enjoying the car. Or get it unloaded soon after. There's better ways to spend your time for sure!
Senior Member
Joined: Feb 2015
Posts: 435
Likes: 81
From: New Zealand
W204 C200, BMW E30 M3, 1980Gt Mini, Toyota Corona, KTM 200 EXC.
I think you need to get all fault codes wiped and then drive for a week and have them re-scan for problems and start from there.
