No compression in number 5 cylinder 6.7 cumins

[CaptainMike]

Yes, the full name for it is connecting rod and it connects the piston to the crankshaft. There are several things that can go wrong with any of the moving parts, but no one can simply divine that by intuition without at least pulling the head and oil pan, I don't care what Master Diesel guru title one has. That actually sounds lazy to me, or more likely the dealer mechanic isn't paid enough for diagnosing the problem correctly. He is well paid to replace a whole engine rather than to repair it in frame. It's a crappy game for dealer mechanics, but each job they do is for a set price, piecework if you will, so their incentive is to try and get the most value for their time. Anyhoo, here's a nice shot of a piston assembly:

 

[CaptainMike]

Side note: You might still need to replace part or most of the engine and it will be expensive no matter what.

 

[Nick]

Yes it is the connecting rod . It is attached at one end to the piston and the crank shaft at the other . A bearing may have seized causing the rod to go south . In larger diesels they can reline the cylinder with a new sleeve . I had a Detroit 8V 92 come loose it bent every rod in it but the crank and block and cylinders were good and it was rebuilt . If your crank and cylinders and block are ok you can rebuild it .

 

[n6454g]

T

Side note: You might still need to replace part or most of the engine and it will be expensive no matter what.

True but they won’t know anything until it’s apart correct?

 

[n6454g]

Yes, the full name for it is connecting rod and it connects the piston to the crankshaft. There are several things that can go wrong with any of the moving parts, but no one can simply divine that by intuition without at least pulling the head and oil pan, I don't care what Master Diesel guru title one has. That actually sounds lazy to me, or more likely the dealer mechanic isn't paid enough for diagnosing the problem correctly. He is well paid to replace a whole engine rather than to repair it in frame. It's a crappy game for dealer mechanics, but each job they do is for a set price, piecework if you will, so their incentive is to try and get the most value for their time. Anyhoo, here's a nice shot of a piston assembly:

View attachment 49703

Ok I was correct in my though

 

[n6454g]

Side note: You might still need to replace part or most of the engine and it will be expensive no matter what.

Even doing that would you think it would cost less than buying a new engine or more? I know it’s hard to tell but…..

 

[AH64ID]

When I rebuilt the motor in my 05 it was cheaper to get a rebuild than a motor, plus I think it was a better build and it let me upgrade some deficiencies in the 04.5-07 5.9.

With the 6.7 I think I would go by cost, the stock setup is pretty darn robust.

 

[CaptainMike]

T

True but they won’t know anything until it’s apart correct?

Somewhat true. The first and easiest thing for them to do would be to pull the oil pan. That exposes the crank and rods to a large degree and perhaps even show what's wrong. It's unfortunate that the dealership didn't at least offer you that option.

On that note, the only time I take a vehicle to a dealership is for warranty work. They are are usually the most expensive game in town and you never know which mechanic gets assigned to your vehicle. You could get the Master Diesel Guru or the sloppy couldn't-care-less perpetually disgruntled hack. I've had both experiences with warranty work. The hack I got once actually dropped my transmission while pulling it to replace a leaky rear main seal. The dealership was at least honest enough to tell me it happened, but when I went to talk to the mechanic to get the whole story he was such an ******* to me it was as if I was the reason he dropped the tranny. I'm an easy-going guy and just politely asked a few pertinent questions, but after the way he was treating me I felt like kicking the **** out of the dude right then and there. I have also had very good experiences with very good mechanics, but that is the luck of the draw.

 

[gimmie11s]

Even doing that would you think it would cost less than buying a new engine or more? I know it’s hard to tell but…..

Less. By far.

Buy a remanufactured long block similar to what Brutal_HO posted above. Have a shop install. Done.

 

[CaptainMike]

BTW, are you still flying that 172?

 

[n6454g]

BTW, are you still flying that 172?

No. It was sold off. I wish though

 

[n6454g]

Well got the truck to another shop and they took a look. They stated there is a common problem with the Cummins where they mounted a system to side of the block and if the bolts come loose they break off into the block. They said there is a tech bulletin for the maintenance guys to check when we get oil changes but not known to the general public. The company said depending on how bad the damage is they can fix it at a way lover cost then a new engine and may not have to replace the block etc. they have done a couple already successfully. I will get the name of the system so you all know and can be checking your trucks to so this doesn’t happen to you. I’ll update you again soon

 

[H3LZSN1P3R]

Did they say it was the grid heater bolt? Because that can be an issue and it may only need a piston and head which is quite a bit cheaper than a full rebuild or new engine

 

[n6454g]

Did they say it was the grid heater bolt? Because that can be an issue and it may only need a piston and head which is quite a bit cheaper than a full rebuild or new engine

Yes, that’s exactly what it is. Thank you! I couldn’t remember what they said it was. Well I’m hoping that is all it’s going to be. I know when you have big toys you have big bills but I wasn’t ready at 125,000 miles to have to spend 29k on a new engine like the dealer wanted to do plus the mileage is nothing for a diesel. Still just breaking in. Hahahahah

 

[Brutal_HO]

Well got the truck to another shop and they took a look. They stated there is a common problem with the Cummins where they mounted a system to side of the block and if the bolts come loose they break off into the block. They said there is a tech bulletin for the maintenance guys to check when we get oil changes but not known to the general public. The company said depending on how bad the damage is they can fix it at a way lover cost then a new engine and may not have to replace the block etc. they have done a couple already successfully. I will get the name of the system so you all know and can be checking your trucks to so this doesn’t happen to you. I’ll update you again soon

Did they say it was the grid heater bolt? Because that can be an issue and it may only need a piston and head which is quite a bit cheaper than a full rebuild or new engine

I know H3LZSN1P3R knows this, but just to be clear, the grid heater bolt issue is because the bolt/nut loosen and develop an arc that eventually melts the bolt and the engine ingests the melted off (large parts) aka the nut/bolt chunk when it completely fails. Usually cylinder 5 or 6 gets taken out. Every once in a blue moon, they just go through in small enough pieces that they don't take out the piston/valves and don't also eat the turbo.

"not known to the general public." only really holds true for those that don't participate in online groups/forums. Amongst them, this is a very well know issue. if one is not grid heater deleted, one has to do the wiggle test at least every oil change if not more often. It's also something that every Cummins owner should pass along to every other CTD owner they know that might not be aware. No offense to the OP, but we all know "that guy" (probably several) that only knows how to put fuel in the truck.

 

[flan]

I know H3LZSN1P3R knows this, but just to be clear, the grid heater bolt issue is because the bolt/nut loosen and develop an arc that eventually melts the bolt and the engine ingests the melted off (large parts) aka the nut/bolt chunk when it completely fails. Usually cylinder 5 or 6 gets taken out. Every once in a blue moon, they just go through in small enough pieces that they don't take out the piston/valves and don't also eat the turbo.

"not known to the general public." only really holds true for those that don't participate in online groups/forums. Amongst them, this is a very well know issue. if one is not grid heater deleted, one has to do the wiggle test at least every oil change if not more often. It's also something that every Cummins owner should pass along to every other CTD owner they know that might not be aware. No offense to the OP, but we all know "that guy" (probably several) that only knows how to put fuel in the truck.

Any more info on wiggle test? First I’ve heard of it.

 

[tyler2you]

Any more info on wiggle test? First I’ve heard of it.

Lot's of Youtube videos out there that probably show it better than can be explained. Just search for "Grid heater killer bolt" or something similar. It's basically just grabbing the wire that attaches to the grid heater connection and giving it a wiggle/jiggle. If it feels loose, best stop driving it and get it checked out.

 

[flan]

Lot's of Youtube videos out there that probably show it better than can be explained. Just search for "Grid heater killer bolt" or something similar. It's basically just grabbing the wire that attaches to the grid heater connection and giving it a wiggle/jiggle. If it feels loose, best stop driving it and get it checked out.

Interesting, never was a problem on my old 12 valves. Then they had to go ahead and make it better...

 

[Brutal_HO]

Geno's published a simple test doc

https://s3.amazonaws.com/cdn.genosgarage.com/downloads/TechPDF/GGTech_GridHeaterNutJiggleTest.pdf

 

[n6454g]

I know H3LZSN1P3R knows this, but just to be clear, the grid heater bolt issue is because the bolt/nut loosen and develop an arc that eventually melts the bolt and the engine ingests the melted off (large parts) aka the nut/bolt chunk when it completely fails. Usually cylinder 5 or 6 gets taken out. Every once in a blue moon, they just go through in small enough pieces that they don't take out the piston/valves and don't also eat the turbo.

"not known to the general public." only really holds true for those that don't participate in online groups/forums. Amongst them, this is a very well know issue. if one is not grid heater deleted, one has to do the wiggle test at least every oil change if not more often. It's also something that every Cummins owner should pass along to every other CTD owner they know that might not be aware. No offense to the OP, but we all know "that guy" (probably several) that only knows how to put fuel in the truck.

No offense taken. I guess I’m one of those guys but will be more informed now. The shop is putting a new grid heater system on so it doesn’t happen again. I did get off easy since they only have to replace piston and rod. They said the head and block were still in good shape. I had always taken it to the dealer for oil changes so not sure why they didn’t catch it but I also know they won’t own it especially since it’s 25k over warranty.