Bought car 3mos ago, had diff svc done. Saturday was the hottest day yet this year, and I had the car running a solid 80 on the hwy for a 120 mile trip. On way back, stopped for a drink and smoke was pouring out moderately around the car. Wet under the back, on bottom of gas tank and bottom of both axles, greasy vaporized residue on back bumper.

Does this thing have a relief valve? Overfilled and heat of drivetrain plus ambient temp caused it to erupt? Bad plug? Potential damage done to rear end?

Shop who did the work agreed to look at it. Beyond that, I need to know what to expect and what to demand

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former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL