PeachParts Mercedes-Benz Forum - View Single Post - will 91 350sdl with "crate motor" be Reliable non Rodbender?

bsmuwk · #9 11-04-2019, 05:33 PM

Replacement factory "crate" motors do not fail...at least not in the manner most individuals have been describing all over forums for years. I service about 40 cars with this engine and only one of them had properly bent a rod on cyl 1. You'll find there are engines with replacement tags found on the bellhousing near the transmission on the passenger side. It's an aluminum tag riveted to the block - should you find it, that motor has been replaced. You'll be OK buying that engine!

I've seen a considerable number of these engines misdiagnosed for bending rods, when in fact the head gasket oil passage in between the timing case and cylinder #1 lets go and ends up flooding cyl #1 with oil on start up - you'll have heavy oil burning and a very apparent misfire on colder starts. The exhaust will also start building up a heavy deposit of oily soot. The repair? A headgasket. What causes the failure, no idea. I've stepped up the torque in that area when assembling these engines and it seems to have solved the problem. Though the sample size is small (120k miles on a personal vehicle, and cumulatively 220k among customer vehicles).

I did a customer's 350GD a couple years back that had a catastrophic failure of that oil passage after the owner hadn't repaired it. The truck traveled all of Africa, Greece, UK, etc before the engine hydrolocked itself on it's own oil. I've attached a picture of that failure and of the engine at the end of that whole escapade.

These car's cost money, if you're buying one for utter reliability with minimal investment, you're not going to get it. You'll be spending thousands to get a car together that will be mechanically reliable. Same goes for every MB diesel out there - realistically the operating and maintenance cost of a 560SEL is less than that of the diesel.

If you do find yourself a car, feel free to make the drive up to my shop in Lakemoor to get it checked out, I'm happy to help! I'm a block away from the Volo museum, so it's a cool place to hang out.