First time Dodge owner here. I've been a Mercedes-Benz technician for 13 years and I plan on diving quite deep into taking this truck apart. I bought it knowing it needs a ton of work. I've had a YouTube channel for the last several years focusing on Mercedes-Benz vehicles. You can find me at http://www.youtube.com/@FriendlyMBTech I bought a 1992 400E and proceeded to take apart the DOHC V8 and rebuild it. Right now I am in the process of doing the same thing to a 6.0L DOHC V12. We have a horse and have been needing something capable of towing a horse trailer but didn't want to spend brand new truck money after recently paying off another vehicle. This truck has about 289k miles on it and a misfire on cylinder #4. I've been told it's on its third transmission. It currently has 3 transmission coolers. Two of which are being used. Maybe the original cooler is clogged? The Flowmaster muffler has a rust hole in it. The passenger side door is literally screwed shut. The drivers rear door doesn't open. Slightly more than half the dash is there. I was told the AC works and the heater doesn't. The AC compressor clutch not engaging when the AC is on showed that was a lie. It has quite a few leaks. It has a lumber rack and a camper shell. The Mrs. and I are more excited to take it camping than to tow a horse. I've already started dreaming of upgrades and modifications. I have checked compression on cylinder #4 and its at 100PSI. I also checked compression on cylinder #2 and it's at 155PSI. I already planned on rebuilding the engine anyway so I'm not worried. The heads will probably get replaced in the process, because it would be dumb not to when the engine is already taken apart. I drove it about a mile from the original owners house to mine. It seemed to shift ok. I'm sure there is more but I can't think of anything at the moment. I did a video on it already, if you feel so inclined to watch it.

 

Welcome to DF!

There are replacement heads that have thicker decks, less prone to cracking then the stock heads. Clearwater/Odessa cylinder head sell them. If you are looking for a bit more power, there are the EQ Monster magnums, they come in two flavors, stock valve size, and bigger ones. (2.02 intake) They flow better out of the box than the stock heads, and are also better castings than stock.

Couple different places sell replacement upper dash plastic. It's a better variety of plastic, and less susceptible to UV from the sun.

The lower hinges on the rear doors like to seize..... They seem very talented at collecting all the dirt and other crap that blows by the truck. I usually just have the wife hold the handle, while I kick it from inside. Then, just clean 'em REALLY good, hit 'em with some DRY LUBE, and call it a day.

When you rebuild the engine, be sure and fix the plenum as well. (two-piece intake, gasket loves to blow out)

Double roller timing set please.

Use ONLY genuine mopar sensors, and stick with copper plugs. Your life will be much more pleasant.

100 psi is the bottom of the acceptable range, the next one being 155 though, says it is indeed time for a rebuild.

 

I was looking at the EQ heads. More than likely going to go that route. I've already found replacement dash boards. Almost makes me wany to swap over the interior to black. I forgot to mention here and in the video that the headliner is also missing. I'm hoping I don't find anything too crazy when I unscrew the passenger door. I'll order the hinges first. I'll make sure to rebuild the plenum. When I rebuilt the DOHC V8, it had a two piece manifold also that had 8 individual seals that needed to be replaced. I've looked at complete bottom end kits including pistons, any idea if these are any good? I don't want garbage parts. With the MB engine, I used 100% factory Mercedes-Benz parts. Mainly because of my employee discount. Also because no one makes aftermarket parts. Even if they do, they are insanely expensive. The 5.9 kits I've seen come with timing sets but if they aren't double roller, I'll order a double roller set for installation. What's the benefit of the copper plugs VS something more expensive? The engine just happier with the copper? Thank you for the input.

 

Not all crank kits are created equal. Get one from a name you recognize, and should be golden.

Leave it to the germans to over-engineer something.

These trucks simply do not care for the rare-earth plugs. Leads to mystery misfires, that are fun to track down. Some folks have no problems with 'em. Others? Not so much. When we see a thread about misfires here, usually, the FIRST questions is: What plugs do you have installed. I can't count the number of times that dumping the expensive fellers, for the cheap copper fellers, solved the problem.

 

Love that hood release!!!If that is CA truck it should have duel cat's. Looks like rust is not an issue which is a good thing! If you go for the EQ heads do your research. I see a lot of them are not finished, Rocker pedestal/mounts not machined to the same height. Seems they sell the rough castings and it's up to your machine shop to finish them. With 300K it will have to be bored out, I was looking at getting the Sealed Power Moly-graphite coated pistons. They are available in a few different options(cast-forged). Stick with brands that have been around forever, Sealed Power, Fel-Pro, Federal-Mogul or any of the other well known manufactures. I see in recent years Enginetech brand came out. Have no idea who makes their stuff so i stay away. And don't shop on ebay unless you know exactly what you are after. It's beyond overrun with china crap.
Since you work on Mercedes maybe you can give me some help. I have a 2001 CL600 V12. When i bought it the guy sold it with a laptop with the star software and multiplexer. Fast forward a few years and the seems the registration ran out and the software no longer works. Any way around it to get it to work again? Also been looking for a service manual for it, Mercedes doesn't have paper manuals and it seems you have to download a copy of interactive software to get it. I posted both of these questions on a Mercedes forum but got "if you look for it,you can find it" type answers. Any insight would be awesome.