Engine Noise

Bob Rooks · Oct 7, 2011

Affordable said:
it will do the same thing Bob,you will notice the difference in the engine rpm " WHen you loosen that return line also " We bleed off the air there all the time too !

Well I was so curious about this I went out and tried it on my dozer. It had no effect except to make a mess, so I thought I'd try it on my Mustang's Yanmar diesel (which also has return lines) - same effect except a bigger mess.
Well if it works for you then I guess it's okay. :thumbsup::laughing:

markh1 · Oct 7, 2011

I tried loosening the return lines and noticed no difference in rpm as Bob said. Do I need to try the line going into the injector then?

Mark

Bob Rooks · Oct 7, 2011

markh1 said:
I tried loosening the return lines and noticed no difference in rpm as Bob said. Do I need to try the line going into the injector then?
Mark

That's what I would recommend Mark. If you notice a change then the injector is probably OK, but doesn't take "dribbling" into consideration which can only be detected by pop testing at a diesel shop (or you can make your own pop tester if you have access to a jerk pump).

markh1 · Oct 7, 2011

A noticable change in rpm when I removed the injector input line on each injector.

Mark

greg_g · Oct 7, 2011

Before running the engine makes things worse, I recommend you send an oil sample in for analysis. A comprehensive examination can often point to a specific mechanical problem by determining what type metal particles have contaminated the oil

//greg//

bjr · Oct 7, 2011

I had 3306 Caterpillar engine make noise on a wheel loader, the operator thought it could be a connecting rod bearing going out, but, I had the operator start it once more to see if I could tell what was going on. He started it and just about 10 seconds into the trouble shooting the engine quit with oil pouring out the block on the opposite side I was on. A con rod came right thru the block. It took a complete replacement engine and just about 4 days of hard labor to get things moving again. That was about $12000 OOPS. bjr

Bob Rooks · Oct 8, 2011

markh1 said:
A noticable change in rpm when I removed the injector input line on each injector.
Mark

As expected. :thumbsup:
You now have two options, one of which may be inevitable:

1) Follow Greg's advice and spend $25.00 for a spectrographic lube oil analysis to determine how much cast iron, aluminum and steel is in the oil. Also you will get a TBN, fuel dilution %, coolant contamination %, and a bunch of other stuff. If any readings are excessively high you will get a warning in that category. This will take a little extra time for the lab because you haven't established a baseline yet.

2) Drop the sump and go exploring.

markh1 · Oct 8, 2011

I listened again when I ws checking the injectors and it could be considered a popping noise. Where can you have an oil analysis done?

Thanks for the advice and help.
Mark

Bob Rooks · Oct 8, 2011

markh1 said:
I listened again when I ws checking the injectors and it could be considered a popping noise. Where can you have an oil analysis done?

Here is a Google search: Oil analysis - Google Search
I would pick the closest one to you for the quickest turn around time.

This is the one I use (at home and work):
ALS Tribology | Tribology Services | In-Service Lubricant Analysis

What you are hearing could possibly be a dribbling injector over-fueling. You can take them to a diesel shop and have them tested.