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Old 01-22-2002, 10:16 AM
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Tump Tump is offline
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Join Date: Jun 2001
Location: Westchester, NY USA
Posts: 183
Update on HeadGasket Replacement -- MPG Question?

Fellow MB nuts,

Well I did some research and found that the camshaft and stem seals were replaced in 1994, 7 years or approx 100,000 miles ago. Before doing my head I replaced the radiator, expansion tank and overflow tank myself, flushed the cooling system and still after 3 weeks found oil reappearing in the coolant.

So I had the head gasket replaced and the head redone with new Stem Seals, etc. During the job it was found that one pre cat in the OEM exhaust was completely clogged and fused with oil ( I checked this myself and tried after the mechanic did to dislodge this mass with a screw driver -- it would not budge). Apparently, this is where the oil was leaking to. In any case I replaced the header and pre-cat to cat system (its one OEM piece) with a stainless piece manufactured to OEM spec.'s by TimeValve without pre-cats (the new cat I'm told is sufficient to pass inspection -- we will see). This whole job was expensive (I bought my own parts and had the specialists do the work (@$80/hr) coming in for a total cost at a little under $3,600.00. Not bad, however, for a new header-cat system, remachined head and stem seats, replaced valve guides, valve seals, timing chain and timing chain tensioner. The head bolts were within spec.

The car performs amazingly well now, its much quicker and smooter, etc. and burns no oil whatsoever at this point. Job was done 1 month ago. But, after averaging 19 mpg before the job for 6 months, the car now is averaging 17 mpg since the job -- the mechanics' claim to be baffled and they readjusted my air fuel mixture (without charge). Readjusting the mixture did not seem to solve this decrease in mpg.

Do you guys have any ideas or suspicions as to why my car dropped 2 to 3 mpg from its previous average when is should be 2 to 3 mpg better -- at 20 to 22 mpg (as per MB rating on this car 20 city 25 highway)? (I do drive the car a little more agressively -- but drive the same roads the same distances and use the same gas and gas stations).

Rebuit and restored Obsidian Black/Palmino Interior '87300E with Euro Headlights (they are amazing). Wanted OEM 8-Hole 16" Rims with decent tires.

Last edited by Tump; 01-22-2002 at 10:22 AM.
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