Melted piston

[Jnasystems]

Is it ok to run an engine (5.9 cummins) with a piston this bad? There are three that have issues and this is the worst one. Compression was still good on all the cylinders (took the head off because of a valve problem in a different cylinder) but the mechanic wants to pull the engine and replace the burnt pistons.

 

[dodge man]

What year truck? How many miles? It happens a lot on the common rail Cummins, (2003 to 2007?), when the injector sticks open or over fuels and the cylinder gets to hot. This could also be the problem with your valves. The question is, what else is wrong? Its also common when they get that hot that rings will crack and break. Just my opinion, but its time for a rebuild. My experience is based on owning a Cummins but not doing a lot of engine work but reading a lot on the Cummins forums, what ever that is worth.

 

[Snobdds]

The melted piston is the symptom, not the root problem. Like said, an injector stuck open. See if it's the pump or the injector itself.

I would rebuild the motor. That piston will not last long and you'll be in there again.

Live by...it's too expensive to be cheap. And, fix once...cry once.

 

[art]

The piston issue is caused from an injector!!!!! Seen it thousands of times and you might just as well replace them with the injectors! Most pans can be pulled easily and just do an in chassis rebuild with the head being tuned up and a new set of injectors
!

 

[buickanddeere]

Pay me now or pay me later

 

[dodge man]

Also try and get NEW INJECTORS. I've heard its very hard to get truly new ones. Rebuilt ones will often look new and be sold as new. Rebuilt injectors can often be high quality but it sounds like a crap shoot. New injectors also = huge $$$$$. I think were talking 2k.

 

[Bladehauler]

pistons and injectors should be replaced with genuine cummins parts , but since the 5.9 does NOT have replaceable liners , I would pull it and clean up the bores or rebore as necessary.basically full overhaul and be done with it . I run a 2 micron absolute
filter right before the cp3 fuel pump, dirty fuel will cause injectors to wear and stick and the stock filter only filters down to 7 microns on the best filters , 10 micron is the average.

 

[QRTRHRS]

Hmmm, aluminum pistons, no sleeves? Injector issue or not, having had a 5.9 with a few tweaks, I think it's a good reason to run pre and post turbo temp guages.

 

[dodge man]

Aluminum pistons? I didn't think they were but I'm not sure. I think 5.9's can be sleeved but I'm assuming its a harder task than some other diesels that are designed to be replaced.

 

[CJONE]

They are aluminum. Most Diesels have steel reinforcement where needed in the pistons ,ring lands ect. Don't know much about the smaller cummins like the 5.9 but some are "throw away blocks" with no sleeve. You can bore and press a new sleeve in to fix a badly damaged cylinder. Most of your larger engines have either wet liners that seal with O-rings to the water jackets and head gaskets [Cat] or dry sleeve, no O-rings and a sleeve is pushed in to a dry bore and it has a fire ring and head gasket to seal head/combustion chamber [Mack]. In frame it now and fix the problem like the others are saying. The piston is the result of the problem and the new one will look the that in a short amount of time if the problem is not fixed. Diesels aint cheap!!! CJ