I disagree on those mileage numbers. These Mercedes gas engines wear almost as well as the diesels. I've seen several gas Mercedes in the yards with more than 300K, I've even seen one with 450K, most of them were in accidents or rusted to hell. I bought a beat to crap 190E 2.6 once as a parts car, it had 209K miles, and left it at my mechanic's shop for a few days trying to get stuff moved around at my house. He was bored on a slow day and decided to get it running and did a compression test. It tested at factory specs on all 6 cylinders. I'd do a leak down test instead of a compression test, or you could do both. There will certainly be wear on the engine at 245K but I don't think it's probably anything you have to worry too much about. If you can find a good low miles engine for cheaper, that may be more cost effective but your engine might be salvageable.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.