# '04 Cummins 5.9 dying



## Dookie Ray (Apr 9, 2008)

Well, it looks like I'm either going to have to rebuild or replace my 5.9 Cummins diesel motor before too long. Seems like it's dying a little more each day. I know I have 2 bad injectors, but I had another mechanic confirm that I have at least one weak cylinder. Anyone got any suggestions, tips, or recommendations on this such as to rebuild, or just buy a long block and replace it? Who to use (not too terribly far from Lake Jackson)? That sort of thing? Good or bad experiences will be greatly appreciated as well. Thanks

Dook


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## bwguardian (Aug 30, 2005)

Not too sure about the Cummins but on our Powerstrokes the engines are fairly easy to work on...they are just heavy. Most have the full floating wrist pins on the rods/pistons, forged assemblies, roller camshafts, etc. which makes them more forgiving and easier to work on. Years ago, I tore into one and a machine shop did what needed to be done and I reassembled it after one of the guys drove it through high water and hydrauliced the engine. A couple years ago, we bought a truck that had been dusted at 38,000 miles and I bought a test engine with 500 miles on it complete from pan to turbo and fan blad to flex plate minus the starter. We pulled the old engine, sold it, and put the new one in. A crate engine was twice as much as the new one out of the noth east but was still $5,500.00 shipped. I would say if you can find another engine ready to go, that would be the route to go because all the other stuff...turbo, injectors, etc. is going to also go at some point and you can sell some of it to help cover your costs.

How many miles on the clock?


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## Pocketfisherman (May 30, 2005)

What does "weak cylinder" really mean? That can make a big difference in what you do for a rebuild. Did they do a cylinder leak down test, or just a compression check? With a leakdown test you can often hear the air leaking either into the crankcase, or into the exhaust or intake manifold. That will tell you if you just need a head/valve grind, or if you need to also pull the block out and install new rings. Cummins are designed to be rebuilt, parts are plentiful, and a lot cheaper than other diesel brands. If the block and head is not cracked, don't replace it as you have a known good entity there. But before you do anything with the motor at all, I hope you've measured the fuel pressure both before and after the engine filter and at the injectors. A weak lift pump or HP pump can look like a lot of other problems and they will usually fail long before valves or rings.


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## Durtjunkee (Mar 23, 2007)

log on to www.cumminsforum.com and do a LOT of research before you make any rash decisions.

And you may want to call Mike and have him take a look at your problem.
http://www.hotroddiesels.com/
I've spoken to him on different occasions when I needed advice on wrenching on my own Cummins/Dodge.

As a whole, I've found that dodge dealers/service departments are sub-par when it comes to working on a Cummins. I'm sure there are exceptions, but I haven't found one. So far, I haven't found a problem that I couldn't diagnose and fix myself by using my computer.


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## Pocketfisherman (May 30, 2005)

Don't know anything personally about this, but saw it in Austin craigslist. Great deal, a cummins short block for $1500

http://austin.craigslist.org/pts/2150708674.html


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## gitchesum (Nov 18, 2006)

Please make sure they are doing the leak down test as suggested. I'm going to attempt to attach a picture of what has come through Mike's shop at HotRodDiesels. Baffled the both of us as to what would cause it.

As mentioned, with a leakdown test, you can almost pinpoint where the problem is. Could be something like the valve you see in the pic. It could also be venting into the crankcase which means you'll need a short block. Mike can also take care of your injector issue. If you have one leaking, it can cause major issues.

Keep an eye on your fuel level too, if your level increases, that may be the case and you're just shortening the life of your engine by running it like that.


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