Regular Gas used where Premium required-Mercedes 2002 E320 (187K miles)

Chaud

Sr. Member
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Dec 18, 2006
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I have been using regular gas in my car for 3 years when the car manual says Premium gas only. I made two assumptions before I switched to Regular
1. Car electronic system will notice this and automatically adjust to low Octane (87) gas.
2. Being switched to low octane I may get 3 to 5 miles per gallon.
Recently I read this type of thinking is wrong. Because regular gas will build carbon inside the engine and on the valves which will ruin the performance of the engine. Now I am worried if this is true or not. If so can I use some additive in gas or in oil to remove this carbon deposits or it is too late. The car is running fine but performance has suffered a bit and makes some lifters type of noise. Thank you for your opinion and suggestion.
Chaud
 

kev2

wrench
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Nov 14, 2006
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your fine - likely a very small performance issue- if you worry about CARBON build up - add 1 can of "seafoam" to gas - there is also TECHRON by chevron another brand that I would suggestt...
the lifter type noise ? unlikely fuel and as the the CEL is OFF and no codes... may try to isolate the noise top bottom front rear of engine and post again
 

Chaud

Sr. Member
Joined
Dec 18, 2006
Messages
172
Points
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Thanks. I feel much better. I will try the "Seafoam".
Chaud
 
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