Well, I just answered your question before reading your string at the oil in water 300TE, my first fail on a 91 300E 3.0 was at 75k....lasted to 225K....all w/MB coolant , no dogging and no overheats....so that's abbout a 150K DIY job...I'd say not bad considering it was just a lift, clean, drop job at 75K, but a warning, .......I could not get to the last third 90 degrees of torque as called by the book on account of a stripped torx head so I left it at that and at 226K...where do you think it failed?........you guessed it ....where I could not get to the full spec torque at bolt 14...so follow instructions....Later
91 300E 226K

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Adam Reinosa
91 300E 190K
81 911SC 210K
61 MB 190C 90K - sold...sigh.
70 914-6 - DUI victim - sigh
911T - Fire victim
Renault Dauphine '62
67/Cougar GT;70 Challenger 440 Mag
www.wetstart.com - OEM future option coming soon