I've got all the creature comforts and mechanicals taken care of with my family's 82 300D, 180K miles. The car runs great and the 20 year old interior is holding up with the kids and general abuse.

The overboost protection switchover valve was bypassed on purpose by original owner's mechanic.

Should I fix this or is this a turbo-engine safety devise that never saved a 300D?

If you say it's risky to bypass it I will plunge into the repair. If it serves no practical purpose i'll ignore it. Anything in between puts it on the back burner (could take up to a year to getting around to fixing it). I guess these systems get bypassed because the valve goes bad or maybe it's just a hose problem.

If anyone has an engine disaster experience due to a bypassed system i'll be really concerned.

Thanks

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1972 450SL
1982 300D Turbo