I recently had to remove the EGR Heat Exchanger and its bracket to replace a leaking fuel line. Got the line installed okay, except now the power pack (the engine and all its connected parts) is squealing. I've attached an audio file if anyone wants to be totally annoyed. I've tried to localize the squeal, but it is so pervasive that it seems to be coming from everywhere. It is also quite loud. BRIEF HISTORY: I recently changed the main hydraulic filter, pilot filter and the hydraulic oil. I followed the manual's PUMP STARTUP PROCEDURE by filling the pumps with oil and bleeding all the air from the pumps. As mentioned above, I also recently had to remove both the EGR Heat Exchanger and its bracket to replace a leaking fuel line. To do this, you have to drain most of the coolant from the engine, but it goes right back in once everything is reassembled. Nothing has been done with the machine, except cycling the boom and dipper to build up hydraulic pressure in the system since doing the above repairs. I also removed the serpentine belt in case the alternator or A/C compressor were seized, but the squeal remained. I'm really afraid of doing anything with the machine in case the squeal is damaging things. Anyone have any thoughts? EDIT: I forgot to add some important info: Engine: 6068HT073 Serial number of excavator: 1FF290GXEEE706050
Today, after charging the batteries all night, they held their charge and I was able to start the engine. The squeal was still there, but I believe that it is coming from the high pressure fuel pump. The fuel line that I replaced was item 10 below, which I believe is the "pump to secondary filter fuel line". During the search for the leaking line, many lines were removed from the pump and examined. Upon reassembly, no priming, or purging air from the system was performed. Is priming necessary for the HP pump? Could this be why it is squealing? Right now, he machine runs fine, with no coughing or spitting, but I am not running it for long without knowing the cause of the noise.
I assume this noise only started since the repair? Does it change with rpm? Did you ever look at the charge air cooler hoses? Also, check your exhaust manifold and all its mounting hardware. The 6068 likes to break bolts, which in turn can cause whistling. There have been some manifolds that crack as well. If your engine goes into an auto-regen (temp light "on" in the monitor), the exhaust throttle closes and raises the exhaust back-pressure, which can make the whistling worse.
Yes, it started on the first start after the repair. During the audio file, I did vary the throttle from idle to about 1/2 speed and the noise did seem to change with the RPM in a lagging fashion. Yes. It was during this check when I noticed that the noise was coming from the direction of the HP fuel pump. Putting 2 and 2 together, I deduced that it was the HP pump (but probably in error). It was during this search that I noticed a pin hole leak in a rubber water hose that lead to the EGR heat exchanger. So I let the machine cool off, then drained about 4 gallons of coolant in order to remove the hose. I picked up the hose last night and today will install the new one. Where is the exhaust throttle? Can its state be observed from the outside? I'll perform a thorough search of the exhaust system today and report back later.
Disregard. I confused your machine with another. Yours has an intake throttle. Still check the exhaust manifold studs.
Well, I am a happy camper! mg2361, you were right to check the exhaust connections. The reason that it sounded like it was coming from the HP pump, was that it was the exhaust entrance to the EGR exchanger that was the issue - right above the pump. One of the screws (the one that can not be accessed) was missing and the other two were loose. I picked up a like screw in town and proceeded to install the connection correctly. The screws weren't engaging properly, so I removed them all - and found this: When it was assembled, it was complete. About 20 minutes of squealing fatigued the hell out of the gasket. I went to town again in search of a replacement. Turns out that a 1969 Chevy 350 engine exhaust gasket is a very close replacement. Installed the replacement and this time made sure that all three bolts were secured and properly tightened. No more squealing! This saga has hopefully ended. I can only hope that the next one will be just as exciting!
Never would have guessed that screech was an exhaust leak. Thanks for posting this update. Glad you figured it out.
Today I'm going to put the engine cowling back on and I'm going out to bully some trees! I'm going to have some fun!
I work on a 644K that does the same thing, sounds like a turbo about to come apart but it's an exhaust manifold gasket. With everything involved in changing that gasket the owner is content to let it squeal for awhile.