Sounds like a rod is letting go

[MStaggs]

03 235 hp.



I was cruizing down the hwy towing my trailer and it deveoped what I consider a very loud knock. It seems to be lousest on the passenger side but same on top and below the motor.

EGT's are WAY down and there is no smoke.

Oil level is fine, boost pressure etc are fine.

Checked the valve train and all appears to be fine.



Here is some video -





YouTube - 100 3140



YouTube - 100 3139

 

[07 ThunderRoad]

Sounds bad . Did you check the exhaust manifold for an exhaust leak - cracked exhaust manifold? Maybe thats all it is... . if your lucky.

 

[Wingate]

03 235 hp.



I was cruizing down the hwy towing my trailer and it deveoped what I consider a very loud knock. It seems to be lousest on the passenger side but same on top and below the motor.

EGT's are WAY down and there is no smoke.

Oil level is fine, boost pressure etc are fine.

Checked the valve train and all appears to be fine.



Here is some video -





YouTube - 100 3140



YouTube - 100 3139

Since EGT is way down and there is no smoke, I would check the fuel system. It could possibly be a fuel knock. Does the truck usually produce a little fuel smoke?

EGT being way down sounds like a lack of fuel delivery.

IF thats a mechanical knock, I would pull the oil filter and cut it open. You should see lots of metal in the filter.

 

[HBarlow]

Rod bearing or crankshaft failure in a Cummins B motor is pretty rare. I don't remember ever hearing of one here on TDR site. I'll be surprised if it is that bad.

If you kill one injector at a time you should be able to eliminate the noise and at least isolate the cylinder where the problem is.

 

[Prairie Dog]

That doesn't sound like bottom end to me ~ I agree with the fuel issue scenario.

 

[TFucili]

My first thought was a broken rocker arm, but you you checked the valvetrain,

My next thought was a cracked flexplate, but you mentioned the low EGT, so I'll have to chime in on the side of a fuel supply issue. Injector kill test, or some probing with an infrared gun, maybe. Have you eliminated the Banks box?

 

[MStaggs]

I will remove the 6 Gun and check it out.

I have been told by many people that as long as there is oil in the crankase, these things dont have rod problems - ever.



How do you kill the injectors one at a time?

 

[Vaughn MacKenzie]

Hopefully not a piston but the achilles heel of the CR system is a faulty injector can kill a piston fast, even without much drama such as rattling, smoke, etc. Even a slightly hung-up injector turns into a mini blowtorch and quickly does damage, even without the pyro going very high.

 

[TCDiesel]

Perform the injector kill test to find problem hole, One Injector maybe have cause this or is causing the Knock,IMO its a bend rod.

 

[HBarlow]

Groan. I feel for the OP. A bent rod sounds very expensive.

Can a fueling problem with one injector bend a rod but not destroy a piston?

 

[TCDiesel]

Groan. I feel for the OP. A bent rod sounds very expensive.



Can a fueling problem with one injector bend a rod but not destroy a piston?

Yes. . HB CR Injectors are out right ,down Right any way you look at them Nasty. . I just cannot figure out WHY owners Buy CR injectors form questionable sellers, that don't know nothing about CR. They will tell you everything you want to here,But will get disgruntle when you ask questions. If they will not answer your questions,My suggestion is to hang up and move on to someone that will.

 

[HBarlow]

Yes. . HB CR Injectors are out right ,down Right any way you look at them Nasty. . I just cannot figure out WHY owners Buy CR injectors form questionable sellers, that don't know nothing about CR. They will tell you everything you want to here,But will get disgruntle when you ask questions. If they will not answer your questions,My suggestion is to hang up and move on to someone that will.

I don't understand that either. I quietly groan and roll my eyes when I read posts where members discuss buying aftermarket performance enhancement parts from vendors with a tricky line of bs to sell and little else.

It's their money so unless they are attempting to blame Dodge or Cummins and pursue a warranty claim I try to keep my mouth shut and fingers off the keyboard.

 

[Vaughn MacKenzie]

MStaggs a couple other things to check out. . . with engine running take the oil cap off and see if the oil vapor is pulsing.



Listen to see if you hear any odd noises coming out the tailpipe.

 

[Dieseldemon]

Do a compression test sounds like a scuffed piston I don't mean to be a bearer of bad news but a compression test will clear up the ? I had an 03 that sounded just like it the rings in #1 and #6 were broken and some of the pieces got on top of the pistons and hit the head the gouges in the cyl were so deep I had to sleeve both cyl.

 

[WBacon]

I did not see one in the second video but... do you have the factory jake brake with the vacuum pump. When my vacuum pump let go, the first time, I thought it was a major engine problem and it just turned out to be the noise from the pump when it had failed. It was a pretty convincing knock!

 

[SRadke]

Sounds like a bad injector to me but I recently fixed a couple 03's with dropped valve seats. Roll it over by hand to see if there is debris on top of a piston. Also, double check the valve clearance. Look for a clearance that is too tight OR too loose. Depending what happened this could go either way.

-Scott

 

[Motorhead]

Sounds like a bad injector to me but I recently fixed a couple 03's with dropped valve seats. Roll it over by hand to see if there is debris on top of a piston. Also, double check the valve clearance. Look for a clearance that is too tight OR too loose. Depending what happened this could go either way.



-Scott

I second what Scott says... sounds like top end valve train noise.

LET US KNOW WHAT YOU FIND.

 

[MStaggs]

No Jake brake - its an auto.

 

[RVTRKN]

Have you ever over reved the engine, that would of caused it to float the valves, causing a bent valve stem or push rod.

 

[sag2]

You need to buy at least one cap off tool and kill one (two is better) cylinder at a time until the noise goes away. Fuel knock is usually a scored cylinder.