Sam196370

'91 560 SEL - I have the motor out (again) - I was going to take off the heads and bring them to be rebuilt. I've read that the bolt threads in the block need to be drilled and helicoiled; I thought this would cost $500+/-. I was told that this job - JUST drilling & helicoiling the bolt holes in the block, remember I'm bringing the engine to the shop with heads removed - would be 2 days of labor or around $1,500. Is this the market price for the job? I feel like if I had the stencil I could do it in a day.
If anyone knows of someone in the tri-state area who has the stencil and might charge a more reasonable rate, I'd appreciate it if you would let me know.
Thanks

elolson

I had my heads pulled and gaskets replaced by MB of EL PASO. They came out just fine and did not have to be tapped and helicoiled. Maybe see if they need it or not before shelling out the cash.

hineywineries

MB really mucked up when they came out with the aluminum block on the 3.8 liter engine. They used regular steel bolts in aluminum. When the bolts were removed after many years of service to do a valve job, the threads came with the bolts. The holes needed to be helicoiled, but the bolt holes are not perpindicular. They are drilled at a 1 degree offset. You need to bolt a special jig to the head. Realizing their muckup, MB used very expensive special alloy bolts on the 4.2 and 5.6 liter engines. Notice the color of your bolts. Standard professional procedure is to clean block threads with a tap. Don't do it. Just fill the holes with carb cleaner and blow out with compressed air.