I took the coach (U-280) in to have the cruise control replaced with a King Cruise Control. Pretty straightforward, no big deal. In doing so, we noticed that the Hydraulic hoses going to the hydraulic fan motor were leaking. OK, replace the hoses. While replacing the hoses we found oil leaking from the HEAD GASKET! Gulp! Had the head pulled and got the ominous phone call: "Don, come over here, you have to see this". A valve was burned, seat was messed up and injectors had to be either rebuilt or replaced. OUCH! And to top it off, the top of the muffler and beginning of the tail pipe have big holes (never showed up from underneath inspection). Resonator on its way. Triple OUCH!
The only good thing is that all of this happened before we began our summer travels (4,000 miles RT to the upper Midwest).
Why this happened is another story.
Don,
Be thankful that this was discovered at home and not on the way to the Midwest. Sooner or later maintenance is needed in areas one just does not want to visit.
Unusual for a diesel to burn a valve. I have only seen one in quite a few diesels I have torn down. Could be related to tight exhaust valve clearance, turbo seal leak (extra oil causing high egt), weak or broken valve spring, too low temperature causing carbon buildup, too high temp causing cylinder head warping or incorrect injection timing. Good to research burned valves in this model engine and figure it out so it does not happen again.
Very possible the oil leaking from the head gasket and the injectors that needed to replaced may be related to the burned valve. Has the engine ever been overheated?
Pierce
Don - curious what shop you're using - Berndt Ramspeck?
Ouch is right. Hope you get all fixed up in time.
Wishing you the best, Don. I know the coach was supposed to be present for a graduation right about now!
Michele: Yup. Bernd is doing as much as he can. We sent off the head to be machined and are getting the rebuilt injectors from a friend of ours in Nebraska. Otherwise, Bernd is doing all of it. I am receiving mixed opinions on replacing the muffler with a resonator. Some say that it is way too noisy. I hope not.
Chris: Another Yup. We were supposed to take the coach down to Galveston this weekend for granddaughter's high school graduation. It's not gonna happen. We'll make the trip via car.
As to the possible cause, we suspect that it began 8 years ago when a Cummins shop removed the lower end to check/replace the rod and main bearings and the lube pump. They didn't machine the head when putting the pistons back in. I have all the receipts. At the time I didn't know any better and never asked them to flatten the head. When the head was removed this past week the inner head bolts were so loose they were removed with a ratchet wrench. Outer bolts required a breaker bar to loosen bolts. There was lots of evidence of oil leaking between adjacent valves/cylinders.
We are not aware of exhaust being loud when standing behind with engine running, or from driver seat or anywhere inside coach with coach going down road. Sure it is a little more throaty, but think of the benefit to the engine with easier breathing out. Many have made the change to Aero and I am not aware of anyone feeling it is too loud or wish they had not made the change. Now is the chance for Aero owners to help Don, pro or con.
Don,
You didn't say what was originally wrong with the engine eight years ago that caused the bearings to be replaced. The engine could have just run out of oil if no auto shutdown. Was there an oil pump failure that caused loss of oil pressure resulting in bearing failure? Rod big end may have taken a pounding requiring replacement or rebuilding. Should have been a very young engine then. Normally, you can replace the rod and main bearings without removing the cylinder head and pistons. If the head is removed, the shop usually uses a straight edge and feeler gauges to check if the head is flat so surfacing the head may not be required. An overheated engine may require both the block and head to be surfaced.
When the head is replaced with conventional bolts, the head is torqued sequentially perhaps three times until the required torque is achieved. Many engines require the cylinder head be re-torqued after a certain number of miles. With later stretch bolts, they are again sequentially torqued to a lower setting and then then turned a specified number of degrees to finish. This stretches the bolt so it will not loosen and usually does not require a re-torque later. Part of any reassembly includes measuring the length of the fastener against the maximum allowed. I have seen some stretch until they contact the bottom of the thread before they are tight, especially if used several times without measuring. While conventional head fasteners may have a recessed six sided allen, the stretch bolts have many more and require a special wrench to fit the recess.
Unfortunate when an engine gets a bad name because of poor shop work. Takes a lot of training and discipline to become a good mechanic. The overall shop attitude has a lot to do with it also. Too bad it caught up with you.
Pierce
Don if you are running thru a tunnel at full bore then you will hear it. If I am near a big wall I open the window to hear it. It is a bit louder at idle if you are outside but regular driving is no issu Linda can sleep on the bed as we run down the road too.
Don, I do not have the Aero but have a "regular" one and the sound is nice, not too loud but a sound of power I guess. Love to open window going thru tunnels etc and have had a lot of good comments from Truckers and their amazement of the "get up and go" of coach, but that is mainly the Bank's that does that.
I highly recommend the Res' change and see no reason to have an Aero stainless one over others. It will last 10 yrs anyway no doubt and has been on for over 2 already. Again I did the install-was easy.
Love it
JohnH
Don,
I want to apologize for not including the following in an earlier post.
You should NOT EVER kick yourself for not telling the shop something that they may have missed as it is their business as trained professionals to put the engine back together with the same several hundred thousand mile TBO potential as a new engine would have. They are paid to be experts or should not be doing the work. All of us have our field of expertise and it's not reasonable to expect us to have the latest service bulletins for our engines or transmissions memorized.
Pierce
Pierce, I wholeheartedly agree. If I, as an owner, know something that is relevant AND perhaps not common knowledge about the item to be repaired I'm obligated to mention it. I'm thinking in terms of history (what has already needed attention), or something that I've been told to be concerned about. I would not presume to tell a mechanic how to go about overhauling an engine, though. I'm NOT a mechanic, and if the person I've hired to overhaul my engine needs my advice about how to go about the job I've picked the wrong person.
We thought ours was just a tad bit loud and swapped the Aero 5050XL for a Magnaflow after the first season. Seems to be the best solution for us.
Michelle, did you have this done just for the benefit or did the muffler fail? Several friends are thinking to do the resonator as the muffler failed, which is not my case. I am not looking for noise, nor care if it not too loud, but to help heat and boost. Did you and Steve see that helped in that area? The forum seems to have many say yes, a fewer say no as I recall.
mike
have a 2000 version of your coach.
Not much more noise, less heat, more power, better fuel mileage.
as Nike would say, "just do it"
It helped boost and milage. A bit less then a mpg pickup. I ran the same route cross country at the same time of year and fill up at the same stations each time. Yes boring I know but it is designed to go from home to the grands house as quickly as I can. Not trying to get good mileage I ran cooler in the mountains and used 173 gallons less fuel for the exact same trip.
Thanks Tim and John, and I know Dave likes, and Ron.....I will see how Berndt does for Don H and Don C, that way I can get done locally if he does a good job. I am partly just reluctant for someone to mess around with things about the engine but I am not able to do myself and he seems a reasonable price......I want to be sure it done right, with insulation and so on that some of you have emphasized. Maybe get in June, will see if he can then, if not in fall.
mike