CDI Fuel Freeze up in Winter
I parked my CDI outside for 2 days with temps holding -21F. When I tried to start the ML today at 6am, it just cranked really slow. After 4 or 5 attempts, I tried the charger box, but same result.
Turns out the fuel I filled up with 2 days ago froze/gelled in the lines.

MB Roadside came but could not jump it either. The guy claimed that I was his 4th diesel customer for the day and no one could be started.
Later, saw a post on another forum that someone was told by a MB CDI engineer that gelling/freezing of the CDI's was a non issue, as the fuel is pressurized from the tank to the pump, and from the pump to the injectors the pressure is too high. Not sure what to make of that, as when I called my service adviser, he told me that all of his new diesels had to be pushed inside service to start them.
When I got home, I got my daughter's hairdryer and "thawed" the fuel filter and injection pump. Half hour later, it fired right up!!!

I guess the CDI's can gell... (MB engineers are you taking notes??)
A co worker (and my service adviser) advised me to always run an additive in the fuel for winter. Anyone else tried this? I got one by Shaeffer Oils called Winter 2000.
http://www.schaefferoil.com/diesel_t...00_winter.html
Any tips or advice welcome.
http://www.powerservice.com/dfs/
Both the Schaefer and the PS claim to be formulated for ULSD engines, so I am hoping for the best, as yet again I become an involuntary test subject for Mercedes.
Also, in the GL forum, the Online Owners Manual sticky advises to use some additive in the CDI's to avoid freeze up. They advise that if freeze up occurs, the fuel system will need to be reheated by pushing the car into a heated garage.

I challenge the person who wrote that to push a CDI that is stuck in -20F weather anywhere.
Cranks ok but big noise from fuel pump . Diesel gells in the lines for shure , car towed to Dealer. This is not suposed to happen they tell me.
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So far I have been using the additives mentioned and no issues. It is still around +10F here, so hard to tell if it is the "warm weather" or the additive.
I was poking around in www.startekinfo.com and noticed there is a DTB for this. It looks like MBUSA is tracking the issue. The form asks the tech to report whether the car was outside and for how long, what is the temp at the time of problem, when and where the last refuel was done, CEL codes etc. It's listed under "Diesel engine cold start conditions.", dated 01/06/2009.
jsmith18, in the prior winters mine had started daily no problem, but this time I did not use the car for 2 days, and had just refueled from a station that had a suspiciously low price...
Would guess they got a batch of summer fuel for cheap and needed the sales???
http://www.startekinfo.com/StarTek/S...tedDocId=10275
Here's the link:
http://hotair.com/archives/2009/01/1...-turns-to-goo/
and here:
http://www.startribune.com/local/sou...aPc:_Yyc:aUUsZ
Vernl, unfortunately for us US owners, no block heater available by MB. I would have to go aftermarket. Canada and most of the world gets one though.
I have had the winter diesel before and there was a slight drop in mileage. Believe me, I will take that any day over a no start occurrence in -20F.
http://www.thedieselstop.com/archive...o=&fpart=1.htm
A couple of the posters seem to know what they are talking about.
I would like advocate that the block heater should be a worldwide factory option.







