Piston damage after egr cooler replaced

ponyboy · March 4, 2009

hi I am new to this sight I have a quick question last week at the shop they had a asset student help me out he replaced a egr cooler on a 6.0l after the repair the truck had a miss I checked it out and it went away on its own after a couple of seconds the next day the shop foramen drove the truck and it started to miss check compression and found low compression removed head and found piston damaged a bent valves but one of the intake valves is full of carbon and the other one is not do you think the asset student might have dropped something in there or can a piece of carbon cause damage to the piston?

Shlep · March 4, 2009

I have seen enough carbon in one intake valve to hold it open far enough to make contact with the piston, and it was shortly after an EGR cooler was replaced. Usually the coolant washes most of the carbon down but every now and again I find one with extremely large carbon "cookies" that the coolant just loosened up and they tend to cause problems.

Jim Warman · March 4, 2009

There's a fair bit of missing info... but, I am usually the guy that creeps out on to shaky limbs...

Would the affected cylinder be on the right side (passenger side)? How bad was the EGR cooler leaking?

A hydrolock is a "relative" thing... depending on the severity, it can be a minor "blurp" or it can be a motor stalling "oh my Gawd". To a witness is unfamiliar or inexperienced, what some of us would consider "significant", may appear innoccuous.

If some artifact (a chunk of carbon would be considered as an "artifact"), fastener or tool had been lost in the motor, one would expect witness marks.... If something physical had been lost in the motor, one would expect noises to be at least as much of a concern as missing. Any witness marks - especially those in the top of the piston, should be inspected closely as their shape and placement may give clues to the cause.

Without knowing the nature of the damage... the SSCC.. it's tough.

Now... I hope you are open minded.... If I enlist the aid of an assistant, it is important that I assess knowledge, skill-set and talents when I assign tasks to him/her. It is equally important to supervise their actions and progress to ensure that they are learning good working habits and improving their skills. Apprentices are NOT "set and forget" machines. They rely on our oversight to teach them work ethic and other skills that will improve their performance in the years to come.

I sincerely hope this youngster will not become a scapegoat.

blown99 · March 4, 2009

May have had a piece of debris fall into the intake ports of the cylinder head and ultimatly make its way into the cylinder. International had a SFN on this. Assembly lione workers would drop a nut that held a bracket in place and not retrieve it and just grab another nut to mount the bracket. The tech removes the intake to replace the egr cooler and the nut falls into the intake reassembles the engine and is lucky if the engine does not bar over. I had this happen in my shop to another tech. I have on many occasions spent over a half hour trying to fish out pebbles from intake ports. Using shop air under the intake, trying to blow debris out does not get everything out. You need to visually look into the port and check for debris. Maybe the piece that fell in your shops engine was to big to immediatly fall into the port and had to be beaten up by the valves to make its way into the cylinder?

Mekanik · March 5, 2009

Have you recovered the piece that caused this destruction? If not, what shape is it? Are you missing any sockets, nuts, bolts, torx bits?

It has never happened to me, but I can see how some dirt, pebble, extra 10mm nut that is laying right next to the intake manifold can fall down into the cylinder after the intake is removed.

We had a scenario just like this about a year ago. A tech in my shop replaced an EGR cooler on a little bus, and the thing came back a week later missing on cyl#4. The piston and head was all beat up. The tech blamed this on "hard carbon". I saw the marks on the piston and the cyl head myself. Whatever is was was perfectly round. It was under warranty and Ford paid the claim. Posted Image

As far as working with a apprentice, asset student or even just a quick-lube tech that wants to help, I think he is pretty much your responsiblity. When I used to work with a guy like this, I would always check bolts for propper tightness, make sure things were installed properly, ect...

dieseldoc · March 5, 2009

I have "think BIG"(caterpillars tech school program) students work with me from time to time. The first day or two they are with me I make them work side by side with me to get a feel for there skills and work ethic. From then on I try not to hover around them I think it makes them nervous, which makes them concentrate on me and not what they are doing. I tell them to ask me any question that pops into there head, ANY question. I tell them "I will not think you are stupid or make fun of you, You are a trainee. Your job is to ask me questions and learn. My job is to answer your question the best I can". I try to teach them to do some research before you do something new, or havent done in a long time. In other words READ the workshop manual(system operation, disasembly and assembly)FIRST, then turn the wrenches.

I have seen carbon wreck some things that you wouldnt think it would. Under the right conditions anything is possible. We have and 07 engine in the shop right now the guy just came in for a rough running engine. Found a piece of carbon stuck to an exhaust valve holding it open just enough it wouldnt seal.