300SDL Acceleration problem when cold.

This winter my 1986 300SDL w/320k original miles has no power until it reaches operating temperature (80 degrees celsius on the dash guage). It starts great, idles perfectly and sounds like all 6 cylinders are firing properly at idle and during acceleration. But it feels as if I'm towing a barge (takes a lot of pedal to get her down the road and top speed going downhill is about 65mph). On really cold days I can go about 2 - 3 miles like this until she hits a little above 80 degrees celsius. When she reaches operating temperature she feels like she just got shot out of a slinghot. Then she'll run 100mph all day long without a problem. When she's warm she'll re-start and run fine. And, on warm winter days, it only takes about a mile for the problem to clear. I've replaced both fuel filters and I run diesel fuel additives every other tankful or so. She feels like she's not getting air... Is something preventing the turbo from spinning up till it gets warm? Fuel preheater problem? Thanks in advance!

[Benzmac]

You could have one or more problems. You could have a fault with the waste gate, Or you might just need some adjustment or a timing chain and sprocket. Have it checked by a knowledgeable tech.

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Benzmac:
1981 280GE SWB
1987 16V
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Thanks Benzmac. The sprocket, cam, chain, chain rail, tensioner, cylinder head etc. were all replaced 2 years ago.... Turbo has never needed repair so with 320k miles, the wastegate might just be the problem.

quote:

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Originally posted by Benzmac:
You could have one or more problems. You could have a fault with the waste gate, Or you might just need some adjustment or a timing chain and sprocket. Have it checked by a knowledgeable tech.

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What kind of oil are you using?? In the winter I exclusively use synthetic Mobil 1 in the lighter weights.. usually 10W30. If I used petroleum oils, like 15W50 the car is sluggish and barely gets out of it's own way till it comes up to temp. Mine is a 78 300CD with 285,000 miles on it and it runs wonderful on the original engine. I've ALWAYS used Mobil 1 5W20 or 10W30. Once in a while when I had it changed they forgot my instruction for the Mobil 1 and put 15W50 in it. I would know that the minute I pulled out of the driveway.

Thanks for the response Dennis. You have a different engine. But in any case I've always run 15-40w year round w/no problems. I've owned the car for over 230k of it's 320k miles. The current problem just started this winter so if oil were the culprit I should have experienced problems in previous years. She really feels like she's not on "boost" until the thermostat hits it's magic number.

This may help someone troubleshoot my problem: When the engine reaches operating temperature - the increase in acceleration is is NOT GRADUAL.... it is IMMEDIATE. I mean, if you've got your foot in the pedal trying to get her down the road when the power kicks in, it'll literally snap your neck back. Then she's as good as new for the rest of the trip.