hs 300e
At this point I would not go with the longer bolt. The most vibration will be at the top of bolt thread. The best choice would of course be to take the head to a machine shop which will cost some big bucks plus your own labor to remove the head. Don't try to run on 3 bolts, you'll end up stripping more. That's the bad news.
Some good news:
The helicoil fix will work on this part, (I did this fix 18,000 mi. ago).
After you tap the hole be sure to clean out any metal chips and oil, then
add locktite (per directions) then the helicoil. Torque to specs to be sure
the repair will last.
I did this repair on my 300e alot of miles back, she's on her way to hit
400,000 miles (I'm going to bring her past 500).
I'm not an expert, just a person that has been fixing and running my
cars for a long time, I have a 20 year old Benz that will travel dependably
anywhere as long as there is good premium gas.
