Rod knock on 2 seperate engines in the same car. What am I doing wrong? - Page 2 - PeachParts Mercedes-Benz Forum

leathermang · #16 04-28-2009, 01:53 AM

This is a tough one.....
It would really be depressing to think you could accidentally wind up with two rod knockers in a row... in such a short time period....
Just for grins do try the suggestion about cracking one injector line at a time to see if that affects the noise....

ROLLGUY · #17 04-28-2009, 01:54 AM

I also need to say, on the first engine the knock sounded like it was on only one rod. The second, it sounds like 3 or 4.

ROLLGUY · #18 04-28-2009, 02:02 AM

Quote:

Originally Posted by leathermang

This is a tough one.....
It would really be depressing to think you could accidentally wind up with two rod knockers in a row... in such a short time period....

Yes it is a bummer, as it takes a lot of labor to take out 2 engines (one from the doner and the bad one) and install the good one. I will surely try anything short of pulling the engine one more time.

Quote:

Originally Posted by leathermang

Just for grins do try the suggestion about cracking one injector line at a time to see if that affects the noise....

I am sure the noise would go away, as there would be no fuel, thus no fire, and no pressure on the rod. However, if it was a rod bearing, the noise would return when the fuel was introduced again.

leathermang · #19 04-28-2009, 02:06 AM

I HEAR THAT !!!!

kerry · #20 04-28-2009, 09:41 AM

Can you post a youtube video of the knock for others to listen to?
The reason I asked about the oil leak was because a serious oil leak can reduce pressure perhaps causing a bearing to fail. Doesn't sound as if that was the case. Did you use the same oil cooler for both engines? If so, could some contamination have passed from one to the other?

tbomachines · #21 04-28-2009, 01:03 PM

Quote:

Originally Posted by ROLLGUY

I would assume that the timing and injectors are fine.

You know what they say when you assume things...

Anyways, a clogged injector (nailing) sounds a lot like a rod knock, try a diesel purge first, then check your valve spacing. Its something you'll definitely want to do if you plan on driving the car at all anyways. Might as well check the timing too, while you've got the valve cover off--especially if the engine has a lot of miles on it.

ROLLGUY · #22 04-29-2009, 01:10 AM

Quote:

Originally Posted by kerry

Can you post a youtube video of the knock for others to listen to?
The reason I asked about the oil leak was because a serious oil leak can reduce pressure perhaps causing a bearing to fail. Doesn't sound as if that was the case. Did you use the same oil cooler for both engines? If so, could some contamination have passed from one to the other?

I don't know how to post on youtube. I used the oil cooler from the good engine (left it hooked up during the swap).

ROLLGUY · #23 04-29-2009, 01:13 AM

Quote:

Originally Posted by tbomachines

You know what they say when you assume things...

Anyways, a clogged injector (nailing) sounds a lot like a rod knock, try a diesel purge first, then check your valve spacing. Its something you'll definitely want to do if you plan on driving the car at all anyways. Might as well check the timing too, while you've got the valve cover off--especially if the engine has a lot of miles on it.

I have a bunch of good injectors, so I could replace them before starting the engine.