Okay after reading on this forum for a while, I have some questions in regards to Aluminum Heads versus Cast Iron Heads. Here are the cars I am looking at '82 to '85 300D and the '81 to '86 300SD, which of these models has the aluminum heads and which one has the cast iron heads and what exactly is the difference? Thanks.

Only the '86 300SD has an aluminum head. This is a newer design 6 Cylinder engine OM 603. All the others are 5 cylinder OM 616 with cast iron heads.

P E H

Well the first and obvious difference is duh they are different metals. The aluminum head engines will not take overheating like the irons and will crack easier. If your cooling system is in good order this is not a concern. The aluminum head engines (60X) are newer, therefore more refined. They get better mileage, are quieter, are smoother running, and also give more power. I would say this is a great trade off to not being able to overheat it. When's the last time you over heated your car? I have a 601 in my 190D, smallest of the 60X series, therefore the slowest. Runs great, burns no oil (leaks VERY little), and for an 18 year old engine I couldn't ask for any better.

I prefer these over the 61X engines. I love them all, and would gladly own them all. Can't go wrong with either one.

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1984 190D 2.2 Auto 220k
2001 Jeep Cherokee Sport 70K
2004 Lexus RX-330 ??K
2005 Chrylser Crossfire LTD 6K

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