Did they do a leak down test? If it is leaking a lot of oil the diagnosis may be correct. Is the exhaust system oil soaked externally?

Is the tailpipe oily inside at the exhaust exit point? If it is dry then the mechanic is probably correct.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

The most common spot for oil leaks on these is the “Stirndeckel” (forehead cover), or front timing cover. Replace that gasket before assuming headgasket.

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Prost!

Also has a massive oil leak on upper back side of engine, not the valve cover.

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1993 e300
1995 e320
1994 e320
2006 s500 4matic
2004 Jeep wj overland
2001 Ducati 748
2004 Honda shadow aero

On the back of the valve cover gasket is a half moon shaped rubber insert that can leak. If the large leak you are describing is at the passenger side rearmost part of the block where it mates to the head it is almost for sure the head gasket. There is a sealing ring/area in the head gasket at an oil passage there that fails frequently.

If you can, replace the head gasket before oil gets into the cooling system.

If you can do a compression test before pulling the head you may save the time of doing a valve job if you are on a budget. May just need seals and resurface. If any guides are worn though it is time for a valve job.

Good luck!!!

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"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I had this exact issue (huge amount of white smoke only when accelerating onto the highway) that was fixed by head gasket replacement. My hypothesis was similar to your mechanic’s: oil spray from the front cover hitting the exhaust during hard acceleration while the engine was still cold-ish. It seemed to stop once the engine was fully warm, and friends driving behind me always said it seemed to be coming from under the car not the tailpipe so you could check that way?

got most of the engine torn down. ill have the head brought over to the machine shop monday. do i need to remove the lower timing cover to replace the chain guides? they seem pretty grooved.

found that the hose on the smog pump was busted up bad.

How much does a 3.2 head weigh?

Is an impact wrench that can do 1000lbs of torque good enough to remove the crank bolt?

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1993 e300
1995 e320
1994 e320
2006 s500 4matic
2004 Jeep wj overland
2001 Ducati 748
2004 Honda shadow aero