PeachParts Mercedes-Benz Forum - View Single Post

eatont9999 · #15 02-25-2014, 08:49 AM

Quote:

Originally Posted by mannys9130

Ah, I see.

The numbers aren't to be trusted 100% as correct, but if they seem like they might be right I'd allow them to sway my opinion on the health of the engine a little. I wouldn't praise the engine or condemn it on principle of the owner's numbers.

It's a little harder to do a compression test on a MB diesel compared to a gas MB. Honestly if the engine starts cold with minimal glow, has an acceptable amount of blow-by, has a nice smooth cold idle, and has great power, I'd be satisfied without doing a compression test. I bet a bunch of people are going to be upset that I say that. That's ok.

Most sellers don't like the idea of you pulling the injectors off their car and doing a compression test. I can't blame them, either. I would not want some stranger and self-proposed MB guru removing anything from a car I was trying to sell. That said, I find it quicker and more prudent to judge the engine by how well it starts and runs. I ask the seller not to start the car before I see it so I can tell what a cold start acts like. The last 300SD I bought only had one working GP but it started up nicely (in the summer) and ran very well. After purchasing the car, a compression test showed 430-450PSI. Unfortunately, the IP was destroyed by a WVO project done by the PO. The symptoms were masked by a failed motor mount.