Are you sure you re-tightened them and back to specs? (measure twice cut once) Just a thought...

From what your saying thought, i'd venture to guess that one is a dud.. FLUID!?, uhh.. there shouldn't be any fluid as they are all rubber and metal. Unless the E300's different (i've only done them on my 240 but the E's are due this spring) but, from what i've seen, what their 'purpose' is meant for, I think that one was the dud. Agreed that's a real PITA job to do actually, not SUPER hard but, I wouldn't wanta do that again for a few years...

Maybe you could get the dealership to change the bad one out? assuming you remember where you put the mount that you heard the "fluid" coming from.. if not, there might be a way to do some diagnostic work and figure out which sides the bad one..

can someone confirm the procedure on how to isolate a bad engine mount maybe? Also, to confirm that engine mounts do not contain liquid?

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1983 Euro 240D 277K
2016 Mazda 6
Coming Soon, 2013 Mercedes E350 Bluetec
Formers:
2012- Mazda 3
2007 Outlander- complete pile
1995 E300 Diesel 208K
2007 VW Passat 2.0T 63K SOLD
2003 Jaguar X-type 3.0 Sport Sold 04/11 w/88K
2009 Lexus RX350 9061 miles. Sold 04/09
2008 Mitsubishi Lancer GTS:Totaled Sept.,09 @ 24,000
2003 Infiniti I35 58K Sold
1984 300 turbo diesel 222K