So I'm just curious if anyone else has seen the sealing material on base of the MAP sensor deteriorate over time and basically just melt away as a goo-ie substance?

I am aware that underhood temps on V12 engined cars can be somewhat ridiculous (I open the hood and let the heat escape wherever possible). I am assuming that the materials used to seal the base of the MAP sensor can only take so many extreme heat cycles before breaking down. Both of my sensors have done the same thing and appear to be in the same state of decay. This causes the sensor to vent to atmosphere and subsequently allows unmetered air to enter the intake manifold.

This became know via a check engine light for B1S1 O2 Sensor DTC, which I called BS on as a vacuum leak to the relevant bank MAP sensor several years ago set the same DTC.

Recommendation: Whenever you get a O2 sensor 1 DTCs, check the MAP sensors!

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Jonathan
1998 S600
2001 E430
1994 E320
1991 560SEL
1994 Turbo R