The 85 380SE only requires regular fuel. I have owned two and currently use one as my daily driver. It does not specify premium unleaded anywhere in the manual, on the dash, or by the fuel filler door unlike my 300E which calls for premium in all locations. I have never heard pinging in the 380SE.

However, due to high mileage, carbon, or marginal timing, etc. (including possible worn chain) who knows if regular is gonna cut it for this car. Might not hurt to put in a tank of 93 and see if the pinging goes away.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

"Rattling valves" is an amateur term. If they truly did rattle, your engine would survive for about 30 sec.

You have pinging.

Use premium fuel.

Set timing correctly.

Fix lean-running fuel injection, vacuum leaks, etc.

Cure overheating. Note: overheating is more often the result, but can also be cause of pinging.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

History lesson: Fuel requirement became posted on instrument cluster when unleaded fuel arrived. It was a reminder not to use leaded fuel.

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Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

Well, pinging, rattling, whatever it is. I have always heard it here referred as "rattling", so that is the term I used.

I will check those mentioned items. Thanks.

I was referring to it not stating to use "premium" fuel, not regular fuel. As a side note..... in fact, it does not even say "unleaded fuel only" on the instrument panel like most cars have, even though we know that all cars sold in the USA in 1975 and later required unleaded. Some even before that could use regular or premium, or required premium.

Quote:
Originally Posted by 86560SEL
I do know that the instrument cluster does not say "premium fuel".