Clank In Engine

[THE SUPERTECH]

This 1996 6.5 has a sound that comes on at cold start but is louder when warm. It can be heard in the passenger exhaust and is louder at the outside of the passenger head. It sounds exactly like a screwdriver taping on the side of an empty coke bottle. I thought it was the waste gate clanking with the exhaust pulses but it was not. A tink, tink, tink sound. Not a tap like a rocker and it is not in the lower end. the oil looks great. There is no change in cylinder balance but the mileage has fallen as this noise has increased. It changes with rpm and is not loud enough to be heard at highway speeds. It is there all of the time. I have a shop and have worked on these engines extensively and have never heard this sound out of one. I am going to tear it down to find it unless someone has some info. It does have a 4 inch exhaust straight out with no muffler. Thanks, Russ.

[Husker 6.5]

This 1996 6.5 has a sound that comes on at cold start but is louder when warm. It can be heard in the passenger exhaust and is louder at the outside of the passenger head. It sounds exactly like a screwdriver taping on the side of an empty coke bottle. I thought it was the waste gate clanking with the exhaust pulses but it was not. A tink, tink, tink sound. Not a tap like a rocker and it is not in the lower end. the oil looks great. There is no change in cylinder balance but the mileage has fallen as this noise has increased. It changes with rpm and is not loud enough to be heard at highway speeds. It is there all of the time. I have a shop and have worked on these engines extensively and have never heard this sound out of one. I am going to tear it down to find it unless someone has some info. It does have a 4 inch exhaust straight out with no muffler. Thanks, Russ.

Your clue is the drop in fuel milage. I'd hazzard that you have an injector on the verge of imminent death. I'm pretty sure you're hearing the pintle slamming shut against the seat. Pretty common with mechanical injectors. I had an '82 Audi 5000 Turbo Diesel with Bosch mech. fuel injection. My engine was making that "tinking" noise, almost exactly as you describe it and under the same conditions. The dealer rebuilt all 5 injectors, and I had no more "tinking", and I gained back 5 mpg (to 25 city, 34 hiway). What kind of milage do your have on your injectors?

[sixnickel]

I had a 6.2 that had a noise that that sounds like your noise description. I could not figure it out, other techs could'nt figure it out. Nobodyever heard that noise before!! It ran good and strong for a 6.2 NA like it always did, but it did have a slight lope and a funny exhaust smell on the right side. I knew something was not right so I pulled the right head off, I heard something hit the floor. As I inspected the head I found a precup (pre combustion chamber) missing, thats what hit the floor!! The precup sit half on the deck and the other half is in the combustion area of the cylinder. The head gasket holds it in place in the head. The head gasket under the precup was gone, missing, not there, fire ring and all gone !!This allowed the precup to move up and down the thickness of the head gasket and also hit the pistion on every stroke. Guess I found noise!! This engine ran about 3000 miles like this. The 6.2/6.5 is capable of making all kinds of strange noises and every one is or could be a different cause!! Thats my 2 cents worth Good Luck and Have FUN!!

[3bals]

I had a simular noise in my engine a couple of years ago. It turned out to be the vaccum pump. The guy that found the problem, took a wooden dowel long enough to reach the pump. He placed it on the pump housing and put the other end up to his ear. (be careful of the belt and fan!) You could hear the clicking. I replaced the pump and all was fine.

Jody

[Husker 6.5]

Oh, the joy of mystery noises. Just turn the stereo up, and it'll go away! (My ex-wife's method!)

[THE SUPERTECH]

I took all of the replies into consideration while looking at this one and did find the problem. I should have given more info about the engine as well. First post, I apologize. This is a 99 block with 18:1 pistons, ported heads, marine injectors, reworked pump, 4 inch exhaust, custome intake, High flow cooling, propane and nitrous injection, gear drive, fsd cooler. The pcm has been flashed to work with the engine. There are 50,000 miles on the engine using nitrous and the propane so it was not the introduction of this that brought this on suddenly. This noise came on slowly over 10000 miles and was not after a change of parts. The oil was changed from rotella 15w40 to Valvoline Cummins Blue 5w30 20000 miles ago. I did get a clogged injector 500 miles ago and replaced the set with marine injectors as well as the lines to avoid problems. We tore it down completely and found a piston contacting the head due to a worn piston pin. I was surprised but they are not factory pistons. I have had pistons in contact with the head before on 6.5 and they did not sound like this. Thanks.

[hilton & sharon]

I have a 1996 4x4 6.5 with the same noise that started over a year ago and i was told injectors needed to be replaced, so replaced the injectors and glow plugs and still have the same noise that i dislike, when i first start my truck u do not here the noise untils it starts to warm up then the noise comes out but from time to time u can stop a red lite and u won't here it but 99% of the time it is there, i have e-mailed all the 6.5 mechanics and went around the area and ask 6 mechanics and no one has an answer other than set the timimg up to take the noise out and 2rpm i believe would help but doesn't solve the problem, if i knew how or who could fix this i would have it done but had no luck! My truck has 126,500 miles uses a couple qts in 3000 miles and the funny thing is that before i had the injectors replaced and could turn on the a/c putting the engine under a load and that would take most the noise out and all i can do now after replacing the injectors is put it in nuetral at the red lite to help the embarrasing sound, if i didn't like my truck so well i would sell it and purchase a duramax or powerstroke. I have four other diesel and none have ever made a noise like this! This 1996 6.5 has a sound that comes on at cold start but is louder when warm. It can be heard in the passenger exhaust and is louder at the outside of the passenger head. It sounds exactly like a screwdriver taping on the side of an empty coke bottle. I thought it was the waste gate clanking with the exhaust pulses but it was not. A tink, tink, tink sound. Not a tap like a rocker and it is not in the lower end. the oil looks great. There is no change in cylinder balance but the mileage has fallen as this noise has increased. It changes with rpm and is not loud enough to be heard at highway speeds. It is there all of the time. I have a shop and have worked on these engines extensively and have never heard this sound out of one. I am going to tear it down to find it unless someone has some info. It does have a 4 inch exhaust straight out with no muffler. Thanks, Russ.

[Husker 6.5]

I took all of the replies into consideration while looking at this one and did find the problem. I should have given more info about the engine as well. First post, I apologize. This is a 99 block with 18:1 pistons, ported heads, marine injectors, reworked pump, 4 inch exhaust, custome intake, High flow cooling, propane and nitrous injection, gear drive, fsd cooler. The pcm has been flashed to work with the engine. There are 50,000 miles on the engine using nitrous and the propane so it was not the introduction of this that brought this on suddenly. This noise came on slowly over 10000 miles and was not after a change of parts. The oil was changed from rotella 15w40 to Valvoline Cummins Blue 5w30 20000 miles ago. I did get a clogged injector 500 miles ago and replaced the set with marine injectors as well as the lines to avoid problems. We tore it down completely and found a piston contacting the head due to a worn piston pin. I was surprised but they are not factory pistons. I have had pistons in contact with the head before on 6.5 and they did not sound like this. Thanks.
Wow! That's one serious motor! Just out of curiosity, how much boost are you running, and what kind of HP and torque are you making at what rpms on a chassis dyno at the rear wheels? Have you thought about or are running water/methanol injection? Could you post pictures of your rig/motor? What kind of mapping on your reflashed pcm, and what year is it and your truck?